Client Preparation

Learning Objectives

After completing this section, you will be able to:

Client preparation also teaches the skills required for successful neurofeedback training. The Thompsons, for example, recommend that clients develop an external and diffuse focus, resembling Fehmi's open focus or satori. They suggest linking this state with an enjoyable scene, feelings of empowerment, and encouraging self-statements. They also emphasize the importance of healthy breathing, around six breaths per minute (bpm), to increase heart rate variability (HRV), which is the natural variation in time between heartbeats, and restore vagal (parasympathetic) tone, the calming influence of the vagus nerve on the heart.

We will cover client preparation in four sections: Orientation for Neurofeedback, Client Preparation with Relaxation Training, Client Preparation with Respiration Training, and Client Preparation with Heart Rate Variability Biofeedback.

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Orientation for Neurofeedback and Procedures

This section covers Neurofeedback Myths, Client/Patient Orientation, Major Stages of the Neurofeedback Training Process, Client's Role and Responsibilities, The Initial EEG Assessment Session, and Mentoring for Neurofeedback Certification. Together, these topics lay the groundwork for a productive therapeutic partnership.

Neurofeedback Myths

Clients may arrive with misconceptions that can undermine their engagement and progress. Four myths are especially common: (1) Neurofeedback electrodes transmit energy into my brain, (2) Neurofeedback equipment can read my mind, (3) Neurofeedback will change me, and (4) My role is to relax while the neurofeedback equipment treats me. Addressing these concerns early builds trust and sets realistic expectations.

Neurofeedback Electrodes Transmit Energy Into My Brain

Explain that EEG sensors work much like the ECG electrodes used to detect the heart's electrical activity. They are passive receivers that monitor electrical changes generated by the brain, and they do not conduct current into the body. This distinction helps clients feel safer and more willing to proceed.

Neurofeedback Equipment Can Read My Mind

Reassure clients that the EEG cannot read thoughts or feelings. While the EEG can reveal whether someone is distracted or focused, it has no access to the content of their inner experience. This clarification helps reduce anxiety about privacy.

Neurofeedback Will Change Me

Swingle (2008) observed: "One element of neurotherapy that unsettles parents and older people in general is the notion of changing the way the brain functions" (p. 15). You can ease this concern by pointing out that we change our brain function every time we learn a new skill, from using FaceTime to mastering a musical instrument. Neurofeedback simply teaches specialized skills that can improve performance and quality of life.

My Role is to Relax While the Neurofeedback Equipment Treats Me

Explain that an electroencephalograph can no more treat a client than a stopwatch can coach a runner. Neurofeedback resembles athletic coaching: it involves skill training and practice both inside and outside the clinic. Clients play an active role in mastering self-regulation skills and transferring them to everyday life.

Because both medicine and psychology use the term treatment, clients and clinicians alike may expect the clinician to apply an intervention that passively produces results. Neurofeedback, like all biofeedback, is fundamentally a training process. It involves the client directly and relies on assessment, education, practice, trial and error, re-assessment, and continued refinement based on the client's progress and level of mastery.

Client/Patient Orientation

Patient orientation begins with an explanation of neurofeedback, self-regulation concepts, and operant conditioning. Adjust the depth of your explanation to match your client's education and prior experience with these ideas.

Some clients want an in-depth explanation of the neurophysiological mechanisms underlying neurofeedback. Clinicians who are prepared to discuss these details transform the client into a genuine partner in the design and implementation of training. The more a client understands what is happening, the more likely they are to offer helpful observations that facilitate the learning process.

Neurofeedback

From the International Society for Neuroregulation & Research's (ISNR) Guidelines for Practice:

Neurofeedback developed as a multidisciplinary treatment modality and is now practiced by a wide variety of providers who may or may not be licensed healthcare professionals who treat mental or other illnesses. Its range of practice includes assessment and treatment for conditions diagnosed by licensed healthcare providers, training for optimal performance (e.g., among athletes, executives, students, performing artists, and other healthy individuals), and both clinical and applied scientific research. In general, neurofeedback involves placing sensors on the scalp of the individual and connecting the sensors to an amplifier and computer. Through these connections, the electrical activity of the brain is recorded and then presented back to the individual on the computer screen in the form of a video game or soundtrack that changes depending on what state the brain is in. This is the "feedback" aspect of neurofeedback that enables the individual to change their brain function and keep the game or sound on more.

Neurofeedback is the process of interacting with an electronic device that measures and feeds back information about brain electrical activity. It provides accurate, timely, and useful information displayed through visual, auditory, or tactile feedback that corresponds to meaningful changes in the monitored systems. The ultimate goal of neurofeedback training is to encourage flexibility, resilience, and the capacity for choice in how the brain responds to challenges.

Self-Regulation Concepts

Biofeedback training aims to teach self-regulation, the ability to control physiological responses without ongoing feedback from an instrument. The ultimate goal is for skills learned during training and self-practice to become automatic responses: a client might automatically attend in class, feel calm in stressful situations, or shift away from physiological patterns that trigger migraines. Four critical ideas underpin this transition: mindfulness, neuroplasticity, operant (reinforcement) learning, and passive volition. Neuroplasticity and passive volition are introduced here, while the learning process, mindfulness, and reinforcement design are explored in the sections that follow.

Neuroplasticity

Neuroplasticity is the ability of neurons and their networks to remodel themselves in response to experience, and it is the biological foundation that makes neurofeedback training possible (Breedlove & Watson, 2020). The learning that underlies neurofeedback depends on interrelated structural and functional changes. These include alterations in neurotransmitter release and binding, modulation of release by interneurons, the formation and elimination of synapses, selection among competing neural pathways, and the strengthening or weakening of connectivity between brain regions. For clinicians, this means that the brain's capacity for change is not merely theoretical; it is the mechanism through which each training session produces lasting improvement.

Passive Volition

Neurofeedback training succeeds when clients create a state of calm alertness rather than forcing change. Attempts to exert effortful control activate the sympathetic nervous system, the body's "fight-or-flight" branch, which is the opposite of what we want. Instead, we aim to engage the parasympathetic nervous system, which promotes self-regulation. Therapists should encourage clients to use passive volition: visualize the desired change and then allow the body to make the adjustment at its own pace.

For clients who have difficulty with visualization, a brief discussion of goals at the beginning of each session can serve a similar purpose. With these objectives fresh in mind, the client can attend to the feedback and observe movement in the desired direction without straining to make it happen.

Understanding Biofeedback as a Learning Process

Think about the last time you learned something new, maybe a musical instrument, a video game, or a sport. You tried something, watched what happened, adjusted your approach, and tried again. That cycle of action, observation, and refinement is exactly what biofeedback is all about. The difference? Instead of watching a ball land in or out of bounds, you are watching your own heart rhythm, muscle tension, or brain waves on a screen.

Picture a client named Marcus sitting in a comfortable chair, breathing slowly while watching a display of his heart rate variability. He notices that when he breathes out for a count of six, the rhythmic patterns on the screen become smoother and more pronounced. He experiments with different breathing depths and tempos, watching the display respond in real time. Over the next few weeks, Marcus learns to reproduce this calm, rhythmic breathing pattern automatically, whether he is stuck in traffic or walking into a tense meeting with his boss.

Peper et al. (2012) describe biofeedback as a way of making invisible physiology visible, a kind of psychophysiological mirror. Just like you use a bathroom mirror to check if your hair looks okay or your tie is straight, biofeedback lets you see what is happening inside your body so you can make adjustments. Without that mirror, you would never know your shoulders were creeping up toward your ears or that you were holding your breath during stressful emails.

More Than Just Clinical Treatment

While biofeedback started as a way to help people with health problems, it has grown far beyond the clinic. Professional athletes use heart rate variability training to optimize their recovery and stay cool under championship pressure. Concert pianists practice finger temperature warming to combat the cold hands that come with stage fright. CEOs learn to recognize and interrupt their stress responses before walking into high-stakes board meetings. A Navy SEAL preparing for a dangerous mission and a college student preparing for the GRE might both benefit from the same basic skills.

Why Mindfulness Makes Biofeedback Work Better

Imagine trying to adjust the temperature in your shower while wearing thick winter gloves. You could not feel the subtle changes, so you would keep overshooting, going from scalding to freezing and back again. That is what biofeedback training is like without mindfulness. You need to actually notice what is happening in your body to make useful adjustments.

Jon Kabat-Zinn (1994) defined mindfulness as "paying attention in a particular way: on purpose, in the present moment, and nonjudgmentally." That last part is crucial. If you are beating yourself up every time your heart rate spikes on the display ("I'm so bad at this! Why can't I relax?"), you are creating exactly the stress response you are trying to reduce. Mindfulness means noticing what is happening with curiosity rather than criticism.

Here is a sobering statistic: research suggests that mind-wandering hijacks somewhere between 30% and 50% of our daily thoughts (Turkelson & Mano, 2021). That is a lot of time spent on mental autopilot, missing what is actually happening right now. Mindfulness training helps clients stay present during biofeedback sessions so they can actually learn from the feedback they are receiving.

Dr. Inna Khazan (2019) uses a vivid metaphor to explain this principle: quicksand. If you have ever seen a movie where someone steps into quicksand, you know that thrashing around makes you sink faster. The counterintuitive solution is to relax, spread your weight, and move slowly.

Emotions work similarly. When you desperately fight against anxiety or pain, you often intensify those very experiences. Accepting uncomfortable sensations while taking constructive action (like practicing slow breathing) tends to work better than direct combat.

Connecting Body, Mind, and Something More

If you have ever had a conversation with someone who was technically saying helpful things but clearly did not care about you as a person, you know that health is about more than just physical measurements. The best biofeedback practitioners recognize that their clients are whole people with beliefs, values, and a need for meaning, not just collections of physiological variables to be optimized.

Major Stages of the Neurofeedback Training Process

This section covers what to explain about the training process, informed consent, and how to set client expectations. Describe each stage of neurofeedback training from intake through graduation and follow-up sessions. Your explanation should address four questions at each stage: (1) What will we do? (2) What is my role? (3) How will this stage address my concerns? (4) How long will it take?

You should also answer broader training questions: (1) How will you assess my progress? (2) What will training cost? (3) What are the risks? (4) What are the limits of confidentiality? Where the evidence for an intervention is weak (Evidence-Based Practice level 1 or 2), explain that the proposed training is experimental, why you believe it is appropriate for this client, and how you will monitor progress and adjust training if results are unsatisfactory. From ISNR's Guidelines for Practice:

Accurately represent the degree of scientific support reported in peer-reviewed publications for assessment and training methods for the various problems to which neurofeedback training may be applied.

The written informed consent document should explicitly designate the treatment as experimental and summarize your explanation covering the eight questions listed above, along with clinic policies. Following ISNR's Guidelines for Practice:

Document their client's consent to the specifics of training, including where and how the client will be touched, acknowledgment of training benefits, risks, and costs. Document their client's acknowledgement of the limits of confidentiality. Document their client's acknowledgment that training will not necessarily achieve agreed-upon goals, either completely or at all. Further document the client's acknowledgment that unexpected changes in the client's experience or behavior may occur during the course of training which may or may not be related to the training itself, and that in those cases, it is important for the client to inform the neurofeedback provider so that the training methods can be either adjusted or discontinued, if necessary, and the unexpected changes can be appropriately addressed. Collaborate with their clients to develop measurable training goals, a clear plan for training, and methods for measuring progress toward those goals. This collaboration includes regular review of progress with the client with the objective of asking for their decision regarding whether the benefit of continuing training merits the cost.

Client's Role and Responsibilities

Clients should be active participants in this learning process, not passive recipients. A therapist can reshape clients' expectations about their role through educational literature, assessment, and initial training sessions. Models that emphasize active skill learning, like Blanchard and Epstein's self-regulation model and Shellenberger and Green's mastery model, tend to produce better clinical outcomes than models that place clients in a passive role.

The Coach Model (Skill Development)

The skill development models proposed by Blanchard and Epstein (1978) and Shellenberger and Green (1986) view biofeedback as coaching toward mastery. The therapist is like an athletic coach: assessing the client, explaining goals, demonstrating techniques, providing feedback on performance, and gradually increasing challenge as skills develop.

Blanchard and Epstein identified five components of self-regulation: self-monitoring (noticing what is happening in your body), discrimination (detecting changes in your own physiological activity), self-control (actually using the skills), self-reinforcement (patting yourself on the back for success), and self-maintenance (keeping up the practice over time).

Assignments and Logs

Practice assignments and daily logs reinforce a client's role as an active collaborator. Assignments are vital for skill acquisition and the transfer of self-regulation from the clinic to everyday life. Daily logs provide valuable information about client practice habits and progress toward training goals.

Clinicians should explain how each assignment addresses the client's goals, demonstrate the activity within the clinic, and confirm that the client is both able and willing to practice the skill. At the next session, review the log with the client to reinforce the importance of practice and logging, and invite the client to help improve the assignment. This collaborative approach builds ownership and motivation.

The Initial EEG Assessment Session

During the initial EEG assessment session, revisit the concept of neurofeedback and discuss how the equipment works. Summarize the purpose and steps involved in skin preparation, explain how the sensors work, and reassure your client about their safety. You may also address clinic procedures to prevent infection transmission. This is an excellent time to encourage questions and correct any remaining misconceptions about equipment and the training process.

Screens will be meaningless to your client until you explain terms like amplitude (the strength of a brainwave signal), frequency (how fast brainwaves oscillate), and z-scores (how a client's values compare to a normative database) and show how software displays them. As your client performs activities, demonstrate how visual and auditory feedback change, and encourage them to tune in to how these changes feel.

Explain how the display will change when your client succeeds, and describe how you will record sessions and monitor progress both within and across sessions. During training, the clinician's role is to encourage the type of passive attention and observation of change discussed earlier. Ideally, the client will become increasingly self-directed, even providing the clinician with evidence of their own learning and success.

Reinforce client orientation by providing brochures or links to educational videos. ISNR provides a Neurofeedback Overview video.

Mentoring for Neurofeedback Certification

BCIA developed a 25-contact-hour mentoring requirement to promote "the development of skills, knowledge, responsibility, and ethical standards in the practice of neurofeedback." See Mentoring for neurofeedback certification on the BCIA website.

Certification candidates can learn from one or several mentors after demonstrating basic instrumentation competence. Your mentor can model how they orient clients to neurofeedback, from explaining the process and countering misconceptions to defining the client's role, selecting practice assignments, conducting training, and providing feedback on progress. Mentors can also share sample forms (such as informed consent documents and practice logs), clinic policies, and procedures that you can adapt for your own practice.

Client Preparation with Relaxation Training

This section explores how relaxation, meditation, and mindfulness interventions prepare clients for successful self-regulation training. It examines why biofeedback and relaxation are distinct but synergistic, reviews the evidence behind the major relaxation techniques, and addresses the common myths that can undermine treatment.

Relaxation, Meditation, and Mindfulness

Smith (2021) views relaxation as a component of a more expansive relaxation/meditation/mindfulness (RMM) construct. Relaxation, meditation, and mindfulness overlap considerably, and understanding their relationship helps clinicians select appropriate interventions for their clients.

There is a bit of relaxation in all of meditation and mindfulness. There is a bit of meditation and mindfulness in all of relaxation. Nearly all texts and training programs teach blends of RMM. Although different techniques clearly have a different pattern of effects, all can be placed on the same psychological map. All can evoke experiences from the same lexicon (Smith, 2017, 2019; pp. 39-40).

Smith states that his definition is based on popular use, meaning relaxation is what most professionals call relaxation. Examples of relaxation exercises include autogenic training, paced breathing, progressive muscle relaxation, tai chi, visualization, and yoga (Smith, 1985, 1986, 1990, 1999, 2001, 2005, 2017, 2019).

For Smith, the core element of meditation is sustaining quiet, simple focus. Focused attention (FA) meditation (Lutz et al., 2015) concentrates on one stimulus, such as breathing sensations. Mindfulness meditation involves quietly attending to the flow of all stimuli, or a restricted domain of stimuli such as sounds, as a neutral observer.

Biofeedback Is Not Relaxation

Although consumers and clinicians sometimes conflate biofeedback with relaxation, they can be completely separate. Biofeedback is information about your body and its performance, nothing more and nothing less.

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Biofeedback Is Not Inherently Relaxing

A high blood pressure reading (biofeedback) can be alarming rather than calming. The information itself does not produce relaxation; it simply tells you about your physiological state.

Biofeedback-Assisted Relaxation Training

In biofeedback-assisted relaxation training (BART), clinicians combine biofeedback with relaxation exercises to teach clients to relax. BART can use individual or combined biofeedback modalities to reinforce relaxation exercises like autogenics, guided imagery, mindfulness meditation, paced breathing, and progressive relaxation (Moss, 2020).

A high percentage of biofeedback treatment follows a stress-relaxation model, in which the purpose of biofeedback training is to cultivate a relaxed state and counteract the effects of chronic situational and personal stress (Moss, 2020).

The Many Pathways to Relaxation

Relaxation practices are remarkably diverse and vary in their degree of structure. An important clinical principle is to discover the relaxing activities your client already enjoys and build on them. The following examples illustrate the many ways people naturally find relaxation in their daily lives.

We can relax through structured exercises like meditation.

We can relax through expressive activities like hip-hop dance.

We can relax through exercise and participation in sports.

We can relax through prayer and meditation.

We can relax by immersing ourselves in nature.

We can learn a great deal about relaxation by watching our pets.

Play is an inherently fun way to disrupt the stress response and increase resilience. Children intuitively understand the value of play.

Urban teenagers can turn a cityscape into an obstacle course for parkour. See the World's Best Parkour and Freerunning on YouTube.

Finally, play can involve spending time with your best friend.

Relaxation Myths

Both clients and therapists share misconceptions about relaxation that can undermine treatment success. These myths include the beliefs that relaxation is like being deeply asleep, that all relaxation procedures produce the same relaxed state, that you must make yourself relax, and that brief versions of relaxation procedures are equivalent to the original methods. Correcting these misconceptions is crucial for effective treatment.

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Myth: Relaxation Is Like Being Deeply Asleep

Relaxation training should teach clients to achieve a state of calm alertness instead of drowsiness. The goal is not to become sleepy or zoned out but to achieve a relaxed yet focused state. Relaxation practice should improve your performance when driving, presenting a talk, or hitting a golf ball, none of which would benefit from drowsiness.

Myth: All Relaxation Procedures Produce the Same Relaxed State

When we administer a psychophysiological profile to a new client, we often see some systems within normal limits and others one or more standard deviations outside clinical norms. Each client has a personalized response stereotypy, meaning a unique psychophysiological response pattern. For example, blood pressure and heart rate might be elevated while skin conductance level and upper trapezius muscle contraction are normal.

Mild and moderate stressors do not produce unidimensional physiological changes. Stressors will trigger changes in some systems but not others: blood pressure and heart rate may rise while skin conductance and upper trapezius EMG do not change. This illustrates the concept of response fractionation, in which body systems react independently to stressors. Stress responses are multidimensional.

If your client's response to stressors is unique and multidimensional, their response to a relaxation procedure will also be unique and multidimensional. For example, a progressive relaxation exercise focusing on forearm tension may lower blood pressure and heart rate without changing skin conductance or upper trapezius EMG. In contrast, a visualization exercise asking clients to imagine lying on warm sand may lower state anxiety without changing blood pressure, heart rate, skin conductance, or upper trapezius EMG. Relaxation procedures produce complex changes in each client; there is no generic relaxed state.

Myth: You Must Make Yourself Relax

A client's strategy during relaxation practice can result in clinical success or failure. When we introduce a relaxation exercise to lower blood pressure, clients should not practice it in a way that triggers vagal withdrawal, paradoxically raising their blood pressure.

Dr. Khazan explains why effortful self-regulation is self-defeating © Association for Applied Psychophysiology and Biofeedback.

Although active volition, instructing muscles to contract, can play a valuable role in progressive muscle relaxation procedures, excessive effort can backfire. Shaffer et al. (2002) reported that high effort in autogenic training (AT) and progressive muscle relaxation (PMR) procedures caused unwanted physiological changes. Effort can trigger overbreathing and suppress the parasympathetic branch, producing vagal withdrawal (Khazan, 2019).

Therapists should remind their clients that relaxation is a state of calm alertness and that you cannot be calm when you force yourself to relax. Instead, therapists should encourage their clients to use passive volition, where they visualize a desired change and then allow their bodies to make the change at their own pace.

Myth: Abbreviated Versions Equal the Original Methods

Researchers often administer abbreviated versions of AT and PMR and then draw conclusions about the effectiveness of these techniques. They may leave out crucial elements of the original procedure, provide significantly less training time in session length and number of sessions, lack expertise in teaching the method, and play recorded relaxation instructions instead of offering live interactive training.

There are three issues with this approach. First, researchers should not be surprised when crippled versions of procedures originally taught over months or years do not produce the profound changes reported by their developers. Second, relaxation training success is greatly influenced by trainer skill and personality (Taub's "person effect"), just like athletic coaching success. Do not blame the tools. Third, recorded instructions have less impact than live instructions and cannot be adjusted to help clients overcome difficulties during a training session.

Two Road Maps for Self-Relaxation

Smith (2016) proposed two self-relaxation road maps that help explain how different relaxation techniques work: self-stressing theory and psychological relaxation theory.

Self-Stressing Theory

Self-stressing theory proposes that we initiate and perpetuate a fight-or-flight response in six ways: stressed posture and position, skeletal muscles, breathing, body focus (attending anxiously to bodily sensations), emotion (anxiety), and attention (worrying about a threat).

Smith (2016) argued that the diverse self-relaxation strategies attempt to remedy these forms of self-stressing. A single family group may address more than one self-stressing mechanism. The table below shows how different relaxation technique families target different self-stressing mechanisms.

Psychological Relaxation Theory

Based on 31 published factor analytic studies and surveys of over 40 RMM techniques, Smith (2021) grouped 25 relaxation states (RMM states) into 6 levels. Several RMM exercises may produce the same subjective state. We recommend that professionals purchase Lehrer and Woolfolk's authoritative Principles and Practice of Stress Management (4th ed.) and read Smith's Overview of Stress and Stress Management in its entirety.

Smith characterized RMM theory this way:

My approach is not narrow-spectrum; it does not focus on a homogenous, static outcome state or trait (e.g., the relaxation response, focused awareness, or nonjudgmental acceptance). Instead, my approach is broad-spectrum and based on four ideas: (1) RMM has many defining effects, (2) these effects inform and influence each other, (3) they change over time, and (4) this change is not random or circular but evolves in a direction that is decreasingly self-referential and increasingly deep and encompassing. Simply, my broad-spectrum model is multidimensional, interactive, dynamic, and directional (for an elaboration, see Smith, 2017, 2019) (pp. 40-41).

Smith (2021) argued that RMM states powerfully reinforce the initiation and maintenance of relaxation practice and are crucial to positive relaxation experiences. They enable clients to communicate their relaxation goals and experiences and incorporate relaxation into their daily lives.

Relaxation training combines deep relaxation and abbreviated relaxation procedures. We can categorize relaxation procedures in terms of subjective and physiological change, degree of sensory restriction, and length of practice.

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Autogenic training (AT), progressive muscle relaxation (PMR), visualization, transcendental meditation (TM), clinically standardized meditation (CSM), and hypnosis can help clients achieve deep relaxation. They produce moderate-to-strong subjective and physiological changes, involve moderate-to-high sensory restriction, and are practiced for intermediate-to-long periods.

Abbreviated relaxation procedures like the Quieting Response (QR) produce mild-to-moderate subjective and physiological change, involve minimal sensory restriction, and are practiced for very brief periods.

Like throat-singing (shown below), deep relaxation exercises help clients experience profound relaxation, creating a template of how relaxation subjectively feels. This template guides relaxation practice and enables clients to first consciously, and later unconsciously, identify when they are distressed. When relaxation becomes automatic, clients may unconsciously detect their distress and unconsciously relax.

Deep relaxation exercises may help counter allostatic load and reset body setpoints for blood pressure, muscle contraction, and stress hormone levels. Finally, the belief that relaxation practice has been successful may increase your clients' perception of self-efficacy (personal effectiveness) and result in an internal shift in their locus of control (perceived cause of individual outcomes like health and illness).

These exercises may create a relaxation template, help clients develop an automatic relaxation response, help clients counter changes produced by distress and reset body setpoints, and increase perceived self-efficacy and internally shift their locus of control.

Abbreviated Relaxation and Transfer of Training

Abbreviated relaxation procedures help clients generalize relaxation skills to the settings outside of the clinic where they spend the most time (167 hours a week) and experience the most distress (commuting, home, and the workplace).

Generalization from a clinic to a client's environment, called transfer of training, is a critical hurdle in psychotherapy and relaxation training. Generalization is why you should practice abbreviated relaxation wherever you are, within reason.

Abbreviated relaxation procedures help clients transfer relaxation skills to their environment by making relaxation automatic. A stress response is a habit that has become automatic after months to decades of practice.

Although you should protect your initial relaxation practice from disruption by environmental stimuli (e.g., noise), generalization requires that you gradually expose yourself to mild distractions like TV, the calico kitten.

A relaxation skill is also a habit, but it is so new that its practice initially requires conscious supervision. The more clients practice a relaxation skill, the stronger this habit becomes. After about 6 months, clients may automatically replace a fight-or-flight response with relaxation when they encounter stressors (traffic slowdown). Abbreviated relaxation exercises may complement deep relaxation exercises in countering cumulative changes produced by distress. These exercises may also help reset body setpoints, increase perceived self-efficacy, and internally shift your clients' locus of control.

To summarize, abbreviated relaxation exercises may help clients transfer relaxation skills to their environment, develop an automatic relaxation response, counter changes produced by distress and reset body setpoints, and increase perceived self-efficacy and shift their locus of control internally.

The Relationship of Biofeedback to Relaxation Training

There can be a remarkable synergy between biofeedback and relaxation training. In BART, biofeedback helps clients refine their relaxation skills by guiding their practice with knowledge of results. Feedback immediately shows clients when relaxation strategies succeed or fail. Biofeedback provides objective, quantifiable evidence of performance success.

Clients often trust physiological measurements more than their perception of improvement. Measurements in microvolts seem more real to them. This information can reassure clients that they have made progress, increase their motivation to practice, and help them continuously refine their relaxation skills.

Relaxation training, in turn, helps clients transfer self-regulation skills learned through biofeedback to their environment. Forty minutes a week of biofeedback training cannot change client stress responses by itself. These 40 minutes must counter the stressors encountered during roughly 6,700 waking minutes each week. Biofeedback training does not have a chance of changing clients' stress responses without weekly relaxation practice. Biofeedback research has consistently shown that successful clinical and performance outcomes require regular, but not daily, relaxation practice.

Autogenic Training

Johannes Schultz (1884-1970), a German psychiatrist, developed AT during the 1920s based on clinical hypnosis research. Schultz was deeply complicit in Nazi-era medicine: he served as deputy director of the Göring Institute, endorsed compulsory sterilization, and took part in the apparatus of the Aktion T4 programme. Schultz described clinical applications of AT to the Medical Society in 1926 and published his first book, Das Autogene Training, in 1932.

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Wolfgang Luthe, a German-born psychiatrist who was Schultz's student and collaborator, introduced AT to English-speaking professionals. Luthe translated Das Autogene Training into English in 1959 and co-authored a six-volume English series on AT from 1969 to 1973 (Suter, 1986).

Schultz observed that deep relaxation and falling asleep are associated with sensations of limb heaviness and warmth. AT assumes that this process is bidirectional. Passively imagining heaviness and warmth can produce a deeply relaxed state. AT requires passive concentration, free of effort or goal direction.

Individuals also use passive concentration to perceive three-dimensional random-dot stereograms. To perceive a hidden image, they must allow their eyes to defocus until they see two patterns. At this point, an image will "jump out."

Luthe Believed That Visualization Is Crucial to Achieving Self-Regulation in AT

From Luthe's perspective, passive concentration reduces cortical interference with maintaining homeostasis by subcortical structures. The transition to a passive, pre-sleep, hypnagogic autogenic state is called autogenic shift. The challenge is to maintain the autogenic state without falling asleep. A client walks a tightrope between active attention and sleep (Luthe, 1979). Check the BodyMindPower video Autogenic Training - A Guided Relaxation for a Deep and Restful Sleep.

Autogenic Therapy

AT is a sequence of six standard exercises, autogenic modification, and autogenic meditation. Therapists often use complete or abbreviated versions of the standard exercises. They frequently dispense with autogenic modification and autogenic meditation. Training can be individual or in a group setting.

The environment should be comfortable with minimal distraction. A client should sit or lie comfortably with good neck and leg support. The ideal position is lying supine on a couch since this minimizes muscle tension and promotes drowsiness. The room should be slightly darkened (Linden, 1990).

Six Standard Exercises

The six standard exercises focus on physiological changes. A therapist prepares the client for the first exercise by reviewing its rationale, the learning process, common experiences, and the mechanics of autogenic training. Each standard exercise consists of a relaxation theme ("heaviness") a client subvocally repeats while visualizing that they are lying or sitting in a comfortable environment like a beach or a meadow (Schultz & Luthe, 1969). A passive attitude is the most crucial element. A relaxed position, conducive environment, and visualization are also important.

AT consists of six relaxation themes.

AT's heaviness and warmth standard exercises (themes 1-2) are divided into seven parts.

The remaining standard exercises (themes 3-6) consist of only one relaxation component. In total, the six standard exercises consist of 18 components. The European practice of 1-2 sessions per component requires almost 6 months to complete these exercises (Lichstein, 1988). American clinicians sharply abbreviate autogenic exercises (Pikoff, 1984), often providing less than one hour of training.

Each training session starts with the formula, "I am at peace." The initial practice may be as brief as 30 seconds per relaxation component (for a total of 9 minutes for one standard exercise). A client may extend performing a component to over 30 minutes as their skill increases. Standard exercises end with taking back procedures: vigorously flexing the arms, deep breathing, and opening the eyes: "Arms firm, breathe deeply, open eyes" (Linden, 1990).

Autogenic Modification

Autogenic modification procedures are used when a symptom like low back pain does not respond to the practice of the six standard exercises. Following a client's mastery of the standard exercises, a therapist may introduce organ-specific formulae or intentional formulae.

Organ-specific formulae modify standard exercise themes (heaviness, warmth, calm and regular heartbeat, and coolness) to treat client symptoms ("My back is warm"). Intentional formulae, which may be reinforcing or neutralizing, increase or decrease behaviors. Reinforcing formulae motivate action ("I am energetic and will practice harder"). Neutralizing formulae reduce self-defeating statements ("My job frustration does not matter").

Autogenic Meditation

Seven autogenic meditation exercises improve visual imagery skills after a client has mastered the six standard exercises. These exercises are designed to assist clients who find visualization hard. The exercise sequence is arranged in increasing difficulty. The client should follow the established order and only advance after mastering an exercise.

A client's visualization skills determine their rate of mastery. Moderate-ability clients may master all seven exercises in one or two sessions; others may require a month per exercise (Lichstein, 1988).

Physiological Effects

Numerous studies report that autogenic training is associated with increased skin temperature and peripheral blood flow, though controlled effect sizes on physiological indices are moderate rather than large (Linden, 1994; Stetter & Kupper, 2002). Vasodilation becomes apparent during the "heaviness" phrases and increases during the "warmth" exercises. The temperature increases often followed the anatomical focus of the "warmth" exercises (Lichstein, 1988).

These studies challenged Freedman and colleagues' (1983) conclusion that AT does not produce hand-warming. The authors assigned Raynaud's clients to listen to 3 minutes of tape-recorded instructions followed by the repetition of the phrase, "My hands are warm and heavy" for 13 minutes over 10 biweekly sessions. These clients did not increase their hand temperature.

Freedman and colleagues' conclusion was indefensible for two reasons. First, they did not use traditional AT. Instead, they used a crippled version that had failed to produce hand-warming in a previous study by Surwit and colleagues (1978). Second, their findings cannot be generalized to all individuals since they were based on Raynaud's clients, who suffered from compromised peripheral blood flow.

AT Efficacy

Quantitative, meta-analytic findings indicated that AT was associated with medium-sized pre-to posttreatment effects ranging from d = 0.43 for biological indices of change to d = 0.58 for psychological indices in the Linden (1994) review, and d = 0.68 (biological indices) and d = 0.75 (psychological outcomes) in the Stetter and Kupper review (2002). The pooled effect size estimates hide considerable variability in behavioral/psychological effects for individual target problems; moderately sized improvements were reported for tension headache and migraine, hypertension, coronary heart disease rehabilitation, asthma, somatoform pain disorder, Raynaud's disease, and anxiety and sleep disorders (Linden, 2021, p. 546).

Recent research continues to support autogenic training's effectiveness across multiple conditions. A meta-analysis of 13 randomized controlled trials involving 576 participants with chronic pain found that AT produced a moderate, statistically significant reduction in pain intensity compared to passive control groups (g = 0.58), with no evidence of publication bias (Kohlert et al., 2022). These findings are particularly meaningful because AT allows pain patients to achieve relaxation without the additional muscle tension required by progressive muscle relaxation, making it gentler for those with musculoskeletal conditions.

A comprehensive 2023 narrative review examining AT's role in mental health identified 29 studies, including seven meta-analyses and systematic reviews, that explored AT's effects on mental disorders (Breznoscakova et al., 2023). The authors found consistent evidence for AT's efficacy in reducing anxiety across multiple studies and medium-range positive effects for mild-to-moderate depression. When used as an add-on intervention, a treatment combined with standard care or psychotherapy rather than used alone, AT showed particular promise for enhancing overall treatment outcomes.

Progressive Relaxation

Edmund Jacobson (1888-1973) received training as a research physiologist and physician. Jacobson started using PMR in clinical cases about 1918 and published case histories in two 1920s articles (Jacobson, 1920, 1924). His most significant research productivity was between 1925 and 1940, when he studied the psychophysiology of progressive relaxation. During this period, he published the classic texts Progressive Relaxation (Jacobson, 1929) and You Must Relax (Jacobson, 1934).

PMR was not widely used until Wolpe incorporated an abbreviated version of this procedure in systematic desensitization. Wolpe designed this behavior therapy procedure to treat phobic disorders. Wolpe (1958) and Goldfried (1971) condensed Jacobson's standard procedure, which covered 50 muscle groups in 3-6 months of training. Wolpe's version trains about 15 muscle groups in 20 minutes (Lichstein, 1988).

Jacobson observed that clients maintain tension not required to perform a task (clenching teeth when writing a check) and are often unaware of that tension. He also discovered using electromyography that muscles usually do not relax even when we lie down. Jacobson theorized that unconscious muscle bracing wastes energy, disrupts performance, and produces stress disorders (Jacobson, 1929). He also asserted that anxiety is correlated with muscle tension, so muscle relaxation reduces anxiety.

Research has shown that the relationship between muscle tension, stress disorders, and anxiety is complex. Muscle tension may be a byproduct of an underlying disease instead of the cause (Suter, 1984).

Jacobson's original procedure trained clients to relax 2 or 3 muscle groups each session until 50 groups were trained. Several sessions might focus on a single difficult muscle group before moving to successive groups. Jacobson's approach was time-intensive, requiring 50-60 sessions in the clinic and 1-2 daily one-hour practice sessions (Suter, 1984). Studies do not show a difference in outcome between Jacobson's original PMR protocol and modern condensed versions (Snow, 1977; Turner, 1978).

In contrast to current protocols in which clients tense and relax muscle groups, Jacobson only asked clients to produce minimal muscle tension early in training. Jacobson's clients mainly employed passive relaxation in which they simply focused on muscle sensations (Lichstein, 1988). For Jacobson, the objectives of progressive relaxation were the development of muscle sense (awareness of muscle tension) and the reduction of useless residual tension. After eliminating residual tension, Jacobson encouraged his clients to develop differential relaxation skills, inhibiting unneeded muscle groups during routine activities. Check out the YouTube video Progressive Muscle Relaxation.

Popular PMR protocols are no more standardized than their autogenic counterparts. There are significant procedural differences (Lichstein, 1988). Watch the University of Toledo video Progressive Muscle Relaxation.

As in AT, clients may be trained individually or in groups. Also, a client reclines or sits in a slightly darkened room with eyes closed. For a conventional protocol covering 16 muscle groups, a client might tense for 7 seconds and relax for 45 seconds. The training sequence may be revised to accommodate a client's needs.

Before training, a therapist should question each client to exclude already relaxed muscle groups and identify problem groups. Spastic or strained muscle groups may be skipped, or the tension level may be passively observed (without additional tensing). A therapist may repeat the tense-relax cycle two or three times for difficult muscle groups (Lichstein, 1988).

PMR Efficacy

Jacobson's clinical applications of progressive relaxation are impressive indeed. However, there apparently are no experimental (vs. clinical) data that validate the method, probably because of the extensive methodological difficulties in conducting an experiment... Although the literature on various forms of relaxation therapy is impressive, descriptions of the length and nature of training indicate either that the research has not used Jacobson's progressive relaxation procedure or that this procedure has been confounded with other methods (McGuigan & Lehrer, 2021).

While Jacobson's original protocol remains understudied, the modified versions of progressive muscle relaxation widely used today have accumulated substantial empirical support. A comprehensive 2024 systematic review analyzed 46 publications from 16 countries covering more than 3,400 adult participants (Muhammad Khir et al., 2024). The authors found that PMR effectively reduces stress, anxiety, and depression in adults. When PMR was combined with other interventions like deep breathing or guided imagery, the combined techniques showed even greater efficacy, outperforming PMR used alone.

The COVID-19 pandemic provided an unfortunate natural laboratory for testing PMR's effectiveness under acute stress. A 2023 meta-analysis of studies involving 227 COVID-19 patients found that PMR interventions significantly reduced anxiety compared to usual care (Seid et al., 2023). The analysis also revealed improvements in depression scores and quality of life among patients receiving PMR. These findings suggest that PMR may be particularly valuable when individuals face high-stress situations where pharmacological interventions are complicated by other treatments or health conditions.

Visualization

Kenneth Pelletier's (1977) classic text Mind as Healer, Mind as Slayer proposed that mental imagery can produce harmful or beneficial physiological changes. Negative imagery can increase blood pressure, heart rate, muscle contraction, and pain.

Visualization, in which a client generates mental imagery that can be somatosensory and visual, is a common element in interventions ranging from autogenic training to behavior therapy. The vivid images created during visualization can help relaxation (standard autogenic exercises), prepare an individual to cope with stressful situations (mental rehearsal), and reduce symptoms such as anxiety, back pain, headache, hypertension, and ulcers. There are marked individual differences in visualization ability, and this capacity may overlap with hypnotic susceptibility. High-hypnotizable individuals who are gifted visualizers may achieve the best results using this strategy (Moss, 2004). Watch the University of Houston at Clear Lake White Cloud Visualization video.

Recent systematic reviews have strengthened the evidence base for visualization techniques. A 2024 systematic review of nine randomized controlled trials examined the effects of guided imagery, a structured form of visualization in which a practitioner or recording directs the client through a specific imagined scenario, on patients facing surgery (Kouhpayeh et al., 2024). The review found that guided imagery significantly reduced perioperative anxiety compared to standard care alone. This is particularly valuable in medical settings where pharmacological anxiolytics may interfere with anesthesia or recovery protocols.

Technology is also transforming how clinicians deliver visualization-based interventions. A 2024 pilot randomized controlled trial compared traditional guided imagery delivered by a practitioner with immersive virtual reality (IVR) guided imagery, where clients wear headsets that display relaxing 360-degree environments (Pardini et al., 2024). Among 72 participants, the VR condition produced substantially larger reductions in state anxiety (d = 2.45) compared to traditional guided imagery. While this technology is still emerging, it suggests that enhanced sensory immersion may amplify the therapeutic effects of visualization for some clients.

Meditation

Meditation is a family of disciplines that teach individuals to alter their consciousness for diverse outcomes, ranging from increased mindfulness to union with the divine. The meditative procedures reviewed in this section come from religious traditions like Hinduism (Transcendental Meditation) and secular practice (Benson's Relaxation Response, and Clinically Standardized Meditation). Graphic © Anatoli Styf/Shutterstock.com.

Transcendental Meditation (TM)

Transcendental meditation (TM) is a form of mantric meditation in which an individual repeats Sanskrit syllables that have been assigned by an instructor based on age or personality.

Benson (1975) identified four components that TM shares with other deep relaxation procedures: a "quiet environment, mental device, passive attitude, and comfortable position" (pp. 112-113). Benson developed a secularized version of TM, called the Relaxation Response, that incorporated these four elements and recommended that clients practice 1-2 times daily for 10-20 minutes. Watch the Relaxation Response: Dr. Herbert Benson Teaches You The Basics video.

Early TM hypertension studies lacked control groups, involved single-group pre-test-post-test designs, and yielded mixed results. Controlled trials of Benson's meditative procedure have not demonstrated clinically significant blood pressure changes in hypertensive individuals (Lichstein, 1988). Check out the 5 min Mantra Meditation for Beginners - Easy Guided Meditation.

Clinically Standardized Meditation (CSM)

Clinically standardized meditation (CSM) is a systematic secular meditative procedure incorporating components from meditative techniques like TM. A meditator selects or creates a mantra (soothing sound), repeats it aloud with the instructor and then alone, whispers it, and then mentally (silently) repeats it with eyes closed. Both the instructor and trainee meditate seated with eyes closed for 10 minutes, after which the trainee gradually returns to ordinary consciousness over 1-2 minutes.

An instructor answers the student's questions about using this meditative technique and then instructs them to meditate alone for a specified period (10-20 minutes) after the instructor leaves the room. The student completes a questionnaire following meditation which is reviewed with the instructor. Then the instructor teaches the following week's meditative exercise and reviews how to control negative side effects. Meditation practice is prescribed twice daily for about 20 minutes and may be shortened if the student experiences adverse side effects (Lehrer & Carrington, 2003).

Mantric Meditation Efficacy

Several meta-analyses of the data have been reported (Ooi et al., 2017; Park & Han, 2017; Shi et al., 2017), and these reviews generally confirm the earlier findings that mantra meditation is of decided value for health and emotional stability. These studies frequently call for more rigor in the design of studies and ask for larger samples. This is sound advice, except for the fact that funding for research on meditation is not easy to come by due to its seemingly esoteric nature, which still marks it as somewhat outside of the commonly accepted parameters. For this reason, research funds for more elaborate studies may not be readily obtainable. Hopefully, adequate support will bring forth such larger studies in the future.

PTSD is a notoriously difficult area to study due to the difficulties in pinning down the diagnosis and acquiring a suitable population for study, for follow-up, and for obtaining reliable outcome measures. Despite such difficulties, however, the general conclusion that mantra meditation can be highly effective in the treatment of many components of PTSD has been repeatedly confirmed (Kang et al., 2018; Metcalf et al., 2016; Cushing & Braun, 2018; Lang et al., 2012; Park & Han, 2017; Harne & Hiwale, 2018), and anxiety remains a major area in which mantra meditation seems to offer considerable clinical help (Cooney Roxbury, 2018; Travis et al., 2018) (Carrington & Lehrer, 2021, p. 403).

Mindfulness Interventions

Mindfulness has been described as awareness of present experience with acceptance, and as a form of awareness that arises before words do (Germer, 2005). Clinicians have developed a family of mindfulness interventions over four decades, including Acceptance and Commitment Therapy (ACT), Dialectical Behavior Therapy (DBT), and Mindfulness-Based Stress Reduction (Khazan, 2019). These interventions teach clients to be in the moment without action or judgment. Mindfulness is not relaxation but can enhance relaxation training as clients nonjudgmentally experience emotions, physical sensations, and thoughts. Check out the Comfort Care Mindfulness Meditation video.

Physical Changes

Lazar and colleagues (2005) used magnetic resonance imaging (MRI) to compare the thickness of the prefrontal cortex and right anterior insula in Buddhist Insight meditators and matched nonmeditators. They found that the 20 meditators had greater cortical thickness in prefrontal cortex and right anterior insula than the 15 matched controls. The prefrontal difference was most pronounced in older participants, which the authors read as evidence that meditation may offset age-related cortical thinning. Cortical thickness in the right anterior insula, but not in prefrontal cortex, correlated positively with years of meditation experience.

A systematic review (Gard et al., 2014) of 12 studies, including 6 randomized controlled trials, concluded that various types of meditation might protect against age-related cognitive decline.

Hölzel and colleagues' (2009) used MRI to measure gray matter changes in the amygdala. Twenty-six stressed but otherwise healthy adults completed an 8-week mindfulness-based stress reduction (MBSR) program in a single-group longitudinal design with no control condition. The investigators measured amygdala gray matter density and perceived stress scale (PSS) scores before and after the intervention. Reductions in perceived stress correlated positively with decreases in right basolateral amygdala gray matter density. Because the design lacked a control group, the association cannot be attributed to MBSR itself.

However, Kral et al. (2022) conducted an RCT that failed to replicate whole-brain or region-of-interest structural changes previously reported for an 8-week mindfulness-based stress reduction (MBSR) course in 218 meditation-naive participants. The authors highlighted the low statistical power of previous studies with sample sizes of 20 or less.

Mindfulness-Based Intervention (MBI) Efficacy

By mid-2013, a meta-analysis of MBIs drew on 209 studies (Khoury et al., 2013), showing comparable effects of MBIs to CBT and psychopharmacology and greater effects in comparison to other control conditions. Other meta-analyses are now showing effects for stress reduction in healthy individuals (Khoury et al., 2015), in primary care (Demarzo et al., 2015), in older adults (Hazlett-Stevens et al., 2018), and in the prison population (Shonin, Van Gordon, Slade, & Griffiths, 2013). An inclusive meta-analysis of psychiatric disorders (Goldberg et al., 2018) examined efficacy by five types of control groups (from wait-list to evidence-based intervention), finding significant improved value both immediately after intervention and at follow-up for most comparisons, with MBIs being comparable to evidence-based alternatives. There are now enough meta-analyses in core areas for a meta-analysis of the meta-analytic studies (Gotink et al., 2015). With the focus primarily on MBSR and MBCT, results show significant improvement in depressive symptoms, anxiety, stress, quality of life, and general physical functioning (Kristeller, 2021, p. 423).

More recent research has particularly focused on university students, a population at heightened risk for mental health difficulties. A 2024 GRADE-assessed systematic review and meta-analysis of 29 randomized controlled trials examined the effects of MBSR among university students (Pan et al., 2024). The analysis found significant reductions in anxiety (SMD = -0.29), depression (SMD = -0.32), and perceived stress (SMD = -0.41). Subgroup analyses revealed a positive relationship between intervention duration and improvements in negative emotions, suggesting that longer MBSR programs may produce greater benefits.

Military veterans represent another population with distinctive mental health needs. A 2024 systematic review and meta-analysis of 13 studies involving 1,131 veterans examined the effectiveness of MBSR for depression and PTSD (Li et al., 2024). Both within-group and between-group comparisons showed reductions in depressive and PTSD symptoms with medium effect sizes following MBSR intervention. Importantly, treatment effects were maintained at follow-up assessments for depression and mindfulness outcomes, suggesting durable benefits. The authors noted that MBSR may offer veterans a complementary approach to traditional trauma-focused therapies.

Hypnosis

The American Psychological Association's Division of Psychological Hypnosis cautions that hypnosis "is not a type of therapy" but instead "a procedure that can be used to facilitate therapy" (Kirsch et al., 1999, p. 3). Instead of hypnotherapy, which connotes an independent treatment like cognitive behavior therapy (CBT), we should use the term "hypnotically-assisted psychotherapy" (Moss, 2004, p. 37).

🎧 Listen to Dr. Don Moss' Hypnosis, Mind-Body Perspectives, and Consciousness Presentation

Researchers disagree on the clinical efficacy and nature of hypnosis.

Barber (1996) views hypnosis as an altered state of consciousness and contends that analgesia involves negative hallucination where normal perception is suppressed. Hilgard (1978) hypothesized that the process of hypnotic induction produces an altered state of consciousness in susceptible individuals that allows them to create physiological changes. Barber (1982) conceptualizes hypnosis as a trait or relatively permanent predisposition to respond to suggestion and believes that the hypnotic process is not simply relaxation. He challenges the need for hypnotic induction (promotion of a hypnotic state) and argues that individuals respond equally well to suggestions without a trance state. Most hypnotherapists agree that all hypnotic procedures involve self-hypnosis (self-suggestion).

Hypnotic suggestibility (responsiveness to suggestion) was measured originally by instruments like the Stanford Hypnotic Susceptibility Scale and the Harvard Group Scale of Hypnotic Susceptibility. Clinicians can administer the recent Elkins Hypnotizability Scale more briefly than the hour required for the Stanford and Harvard scales while achieving relatively strong concurrent validity with the older scales (Kekecs et al., 2016).

Moss and Willmarth (2019) described hypnotic ability as a relatively stable trait when measured over a lifetime. A study of monozygotic and dizygotic twins estimated that hypnotic susceptibility has a heritability index of 0.64 (Morgan, 1973). A heritability index estimates the percentage of variation due to genetic influences. Values close to 1.0 indicate strong genetic influence.

A 25-year longitudinal study (Piccione et al., 1989) reported test/re-test correlations of 0.64, 0.82, and 0.71 for measurements at 10, 15, and 25 years, respectively.

The distribution of this trait in the population is relatively normal, which means that there are individuals with very low and very high hypnotic ability. Moss and Willmarth (2019) caution that about 20% of patients may be poor candidates for medical hypnosis applications due to low hypnotic ability. Interventions to increase suggestibility do not help most of these individuals (Lynn et al., 2015). For this reason, therapists should measure client suggestibility to determine whether to use a hypnotic procedure.

The Role for Biofeedback

Hypnosis can be effectively combined with biofeedback/neurotherapy (Moss, 2004). Wickramasekera (2003) proposed different roles for biofeedback with highly hypnotizable and medium-to-low hypnotizable individuals. He argued that highly hypnotizable clients will best respond to hypnotic procedures and that biofeedback can help illustrate the connection between mind and body. In contrast, medium-to-low hypnotizable clients are often better candidates for more intensive biofeedback training, which may increase their hypnotic susceptibility.

The Promise of Hypnosis in Integrative Healthcare

Most patients show moderate-to-high hypnotic ability and achieve comparable outcomes to validated medical interventions. Moss and Willmarth (2019) advocate inclusion of adjunctive hypnosis in integrative healthcare programs where its addition enhances treatment outcomes.

For this to happen, it is critical that the patient's complaint be one for which there is a strong research base supporting the value of hypnotic treatment. There is good research support for the application of hypnosis for anxiety disorders, depression (including major depression), post-traumatic stress disorder, stress management, sleep disorders, smoking cessation, weight management and eating disorders, and the addictions. There is also strong research support for the use of hypnosis for acute and chronic pain, IBS, colitis, diabetes mellitus, hypertension, skin conditions including psoriasis, chemotherapy induced nausea, and pediatric problems such as anxiety, school phobia, and recurrent abdominal pain (Elkins, 2017; Nash & Barnier, 2008). (p. 500)

Hypnosis for Chronic Pain

Hypnotic treatment is more effective than placebo in producing analgesia (insensitivity to pain) in highly suggestible clients (Jacobs et al., 1995). However, clients with low suggestibility respond to analgesic suggestions at the same rate as they respond to placebos (Miller et al., 1991). While researchers disagree about the mechanisms responsible for hypnotic analgesia, there is convincing clinical evidence that hypnosis can effectively treat acute and chronic pain.

A meta-analysis (Montgomery et al., 2000) reported a moderate-to-large hypnoanalgesic effect (d = .67): the average participant given analgesic suggestions reported less pain than 75% of participants in standard and no-treatment control groups, and hypnotic suggestion reduced clinical and experimental pain comparably. Hypnotic procedures have been successfully used in burn pain, cancer pain in children, childbirth discomfort, dental pain, headache, low back pain, pain from sickle cell disease, and surgical pain. These techniques are underutilized due to misconceptions such as "hypnotized clients are unaware of their surroundings" (Brannon et al., 2022).

Moss and Willmarth (2019) summarized Patterson's review of hypnosis for chronic pain:

Similar to his table related to acute pain, Patterson (2010) presented a table related to chronic pain that included 14 controlled studies of hypnosis (12 randomized), in chronic conditions including fibromyalgia, headaches, cancer-related pain, back pain, and irritable bowel syndrome (IBS)-related pain. Again, all studies found that hypnosis was equal to or better than standard care treatments which included group support, biofeedback, medication, relaxation, Autogenic training, attention control and CBT. (p. 499)

Hypnosis for Surgical Patients

Moss and Willmarth summarized meta-analyses by Montgomery et al. (2002, 2007) on surgical applications of hypnosis.

Montgomery et al. reviewed 20 well-controlled research studies, using meta analytic techniques, and concluded that hypnosis is an effective adjunctive treatment for patients undergoing surgery.

The meta-analysis showed a broad beneficial impact of hypnosis with surgical patients, across outcome categories. Subjective measures such as anxiety and pain, objective measures such as analgesia use, physiological measures, recovery time, and treatment time, all showed comparable beneficial outcomes for patients in the groups receiving hypnosis. The patients in the hypnosis groups showed better medical and psychological outcomes than 89% of the patients who did not receive hypnosis. Later research by Montgomery et al. (2007) showed that not only could hypnosis reduce patients suffering, enhance healing, and optimize recovery time, but that the savings to the hospital were substantial, mainly in reduced time in surgery. (pp. 499-500)

Hypnosis as an Adjunct to CBT for Stress

Clinicians do not have to choose between CBT and hypnosis. Kirsch et al. (1995) reported compelling evidence that hypnosis can improve CBT efficacy.

The 18 studies that were analyzed in the Kirsch et al. (1995) report comprised 20 comparisons of hypnotic with nonhypnotic CBT groups, with a total of 90 effects and 577 participants. Larger positive effects tended to occur in larger samples. The average weighted effect was 0.66, so the average person receiving CBT in a hypnotic context did as well as the person at the 75th percentile or so of those receiving CBT without hypnosis.

Of these studies, Kirsch et al. (1995) identified 14 in which the only difference between hypnotic and nonhypnotic conditions was the use of the word hypnosis during relaxation instructions and training. The average weighted effect size for interventions labeled hypnotic, compared with the same intervention without the label hypnosis, for these 14 studies was d = 0.63. Thus labeling an intervention as hypnotic increases its efficacy by more than half a standard deviation (Karlin, p. 560).

Contemporary meta-analyses continue to support hypnosis as an effective intervention for pain management. A 2024 systematic review and meta-analysis of 70 studies involving over 6,000 participants examined hypnosis used adjunctively with other treatments for clinical pain (Jones et al., 2024). Hypnosis added to usual care produced small but significant additional analgesic effects for chronic pain, medical procedures, and burn wound care, with reductions of approximately 7-9 points on a 0-100 pain scale. These findings are particularly meaningful given that hypnosis carries minimal side effects compared to pharmacological alternatives.

A comprehensive 2024 umbrella review synthesized evidence from two decades of hypnosis meta-analyses across multiple health domains (Rosendahl et al., 2024). The authors found consistent evidence for hypnosis efficacy in acute pain, chronic pain, and several psychological conditions. Notably, hypnosis has achieved Level-I recommendation status from the North American Menopause Society for managing menopause-associated vasomotor symptoms, representing formal recognition of its evidence base. The review also found that adverse events in hypnosis trials are rare and typically mild, supporting its safety profile.

The Quieting Response

Stroebel developed the Quieting Response (QR) abbreviated relaxation exercise to counteract the fight-or-flight response.

🎧 Listen to a Mini-Lecture on Chuck Stroebel's Quieting Response

The 6-second fight-or-flight response consists of four stages.

The 6-second QR consists of four corrective stages.

Stroebel recommended that clients learn the QR in eight learning sessions scheduled about one week apart. The activities for each session were described in QR: The Quieting Reflex (Stroebel, 1982). He advised clients to initially practice the QR whenever they experience annoyances, as many as 50-100 times a day. He cautioned that it would take about 6 months for the QR to become automatic.

While 100-times-a-day practice might seem excessive, it only involves 600 seconds or 10 minutes per day. Stroebel estimated that 80% of clients practicing the QR achieve this level of proficiency and continue using this technique after two years.

Stroebel explained that the 80% compliance rate was due to the minimal time commitment required by the QR and the fact that clients do not have to disrupt daily activities to perform this 6-second exercise. "They controlled the technique; the technique did not control them." (p. 82)

Relaxation Training Issues

Causes of Deep Relaxation Training Failures

No one knows the average quality of instruction in AT and PMR when delivered as part of biofeedback training. There are many reasons that deep relaxation training fails.

Recorded Relaxation Exercises

The professional can benefit from recorded relaxation exercises because they conserve training time, increase flexibility regarding when and where the client can practice, reduce the professional's burnout from the repeated presentation of relaxation scripts, and standardize relaxation script language.

There are many practical benefits of recorded exercises. The cost of therapy may be lower due to fewer sessions. The therapist may schedule more clients. Therapist credibility and client enthusiasm may increase as the exercises produce desired results. Finally, client practice shortens the time to achieve mastery.

From a client's perspective, recorded exercises are desirable because they increase comprehension and retention, improve client satisfaction, motivation, and compliance, provide more consistent instructions and standardize exercises, provide information that family members can understand, allow for practice with fewer distractions, and help the client learn to pace relaxation exercises.

Schwartz and Andrasik (2003) recommended several steps when recording relaxation instruction.

Therapists should consider teaching clients to record exercises in their voices to increase client skills and promote an internal locus of control. We want clients to perceive relaxation as a skill they can refine through practice. We do not want them to use recordings as substitutes for medication. In Wickramasekera's language, we want to promote "skills, not pills."

Research suggests that live instructions may be more effective than taped instructions. A therapist's physical presence may produce more motivating demand characteristics than a recording. The advantage of live instructions may also be due to a therapist's ability to adjust relaxation training to the client's immediate experience and progress. For example, a therapist might suggest changes in sitting position or reduced effort during practice, observing psychophysiological measurements. Finally, a therapist can adjust pacing to an individual client's performance.

Negative Side Effects of Relaxation Training

Striefel (2004) cautioned that BART could produce negative reactions in any client.

🎧 Listen to a Mini-Lecture on Negative Side Effects of Relaxation

Most Negative Reactions to BART Are Due to Its Relaxation Component

While Budzynski (1994) suggested that a thorough psychological history can identify clients with an elevated risk of adverse reaction, therapists must be prepared to respond to problems in clients without diagnosed disorders. Schwartz et al. (2016) advised that while significant severe adverse reactions are rare, mild-to-moderate adverse responses can interfere with training, possibly end promising therapy, and reduce client practice of assigned relaxation exercises.

When clients experience adverse reactions like anxiety, muscle spasms, tics, and increased sympathetic activation, a biofeedback therapist can reassure the individual and adjust biofeedback therapy and home practice assignments. In the rare case of a severe adverse reaction that exceeds the therapist's expertise, they may need to consult with or obtain supervision from a more experienced professional. If they cannot effectively treat their client, they may refer them to another clinician. Nash and colleagues (2001) contend that biofeedback therapists who are not licensed mental health professionals should not treat clients with a DSM diagnosis without licensed supervision.

Deep relaxation procedures like autogenic training and progressive relaxation can result in negative experiences.

Intrusive Thoughts Are Among the Most Common Adverse Reactions to BART or Relaxation Exercises by Themselves

A survey by Edinger and Jacobsen (1982) of 116 psychologists who used a relaxation procedure revealed that relaxation side effects are common. For example, 15% reported intrusive thoughts, and 9% fear of losing control.

The adverse reactions experienced during relaxation training can be grouped as follows.

Functional Overdose

While extremely uncommon, BART may reduce a client's medication requirement for conditions such as asthma, diabetes mellitus, epilepsy, glaucoma, hypertension, and hypothyroidism. Functional overdose occurs when biofeedback training lowers a physiological parameter (like blood pressure) to the point where the client's prescribed medication dose becomes excessive. To prevent this, a client's healthcare provider and biofeedback therapist should know which drugs and supplements the client takes, discuss this possibility before initiating training, and ensure adequate monitoring of the client's medical condition. Graphic © goffkein.pro/Shutterstock.com.

A biofeedback therapist should obtain their client's agreement to consult with the healthcare provider before reducing dosage or discontinuing any medication (Schwartz & Andrasik, 2003).

Physical Exercise

Physical exercise is crucial to psychophysiological health. While an hour of exercise per day may be optimal, physicians often recommend at least 30 minutes of moderate-intensity activity (brisk walking) at least 5 days per week or 20 minutes of high-intensity training (running) at least 3 days a week. Physical activity recommendations for four age groups, drawn from the U.S. Department of Health and Human Services Physical Activity Guidelines for Americans (USDHHS, 2018), are below. The table below was adapted from Brannon et al. (2022).

Exercise Health Benefits

Dozens of more recent studies have examined the relationship between physical activity and cardiovascular mortality. A systematic review of these studies shows that physical activity confers a 35% reduction in risk of death due to cardiovascular causes (Nocon et al., 2008). The same review concludes that physical activity confers a 33% reduction in risk of death due to all causes. Furthermore, both men and women benefit from physical activity, but risk reductions may be larger for women than for men (Nocon et al., 2008). More recent reviews confirm this link (Lavie et al. 2019; PAGAC, 2018). A dose-response relationship exists between levels of vigorous physical activity and reduced risk of all-cause mortality (Samitz et al., 2011), and a large reduction in risk appeared when comparing people who reported no activity to those who reported low levels of light-to-moderate physical activity (PAGAC, 2018; Woodcock et al., 2011). Thus, some activity is far better than none, but there are still benefits adding more activity to some activity (Brannon et al., 2022, p. 405).

A landmark 2023 umbrella review synthesized 97 systematic reviews encompassing 1,039 trials and over 128,000 participants to examine exercise effects on mental health (Singh et al., 2023). Physical activity produced medium-sized reductions in depression (median effect size = -0.43), anxiety (-0.42), and psychological distress (-0.60) compared to usual care. The largest benefits occurred in people with diagnosed depression, HIV, and kidney disease, in pregnant and postpartum women, and in healthy individuals. Higher intensity exercise was associated with greater symptom improvement, though shorter interventions paradoxically showed stronger effects than longer ones.

A 2024 network meta-analysis published in the British Medical Journal examined 218 randomized trials involving 14,170 participants who met clinical cut-offs for depression, either by clinician diagnosis or by validated self-report threshold, to identify optimal exercise prescriptions (Noetel et al., 2024). Walking, jogging, yoga, strength training, and mixed aerobic exercise all showed larger reductions in depression than active controls, with effects comparable to or exceeding those of psychotherapy and antidepressants. Dance produced the largest point estimate, but the authors rated confidence in that finding as very low and declined to recommend it strongly. These findings support including exercise as a frontline treatment option alongside traditional interventions.

Physical exercise reduces mortality, increases life expectancy by an average of 2 years, and is associated with a lower risk of specific cancers (breast, colon, lung, prostate, and rectum), Type 2 diabetes, osteoporosis (decreased bone density), hypertension, cardiovascular disease, and stroke. Moderate physical activity can increase basal metabolism and help clients control their weight, reduce low-density lipoproteins (LDL), increase protective high-density lipoproteins (HDL), and possibly lower triglycerides. Watch the 10 Benefits Of Exercise On The Brain And Body video.

Exerkines

Exerkines are molecules released by tissues like muscles and fat during exercise, and they play a big role in explaining why exercise is so good for our health (Khedkar, 2025). These molecules include proteins, hormones, and other compounds that send signals to nearby or distant cells in the body.

For example, a molecule called interleukin-6 (IL-6), released by muscles, helps improve metabolism and energy production in cells, while another molecule, irisin, can boost brain function. Exerkines help with many things, like slowing aging, improving heart health, and even keeping skin healthy. Because these molecules work together in complex ways, it is hard to replicate all the benefits of exercise with a single drug.

7,000 Steps

The 10,000-steps guideline originated in a Japanese pedometer marketing campaign. A prospective cohort study that followed 2,110 adults on average for 10.8 years found that 7,000 steps were a mortality-risk dividing line. Participants who logged at least 7,000 steps experienced a 50-70% lower mortality risk than those who achieved less than 7,000 steps, regardless of step intensity (Paluch et al., 2021).

Nutrition

Acute and chronic stress disorders may deplete B-complex vitamins (50-100 mg/day), calcium (1,000 mg/day), and magnesium (400 mg/day), requiring their increased intake through dietary sources or supplements (University of Maryland Medical Center Complementary Medicine Program, 2005).

Clients should avoid or minimize caffeine consumption due to its activation of the sympathetic nervous system and potential to disrupt sleep. They should also restrict alcohol intake due to the risk of abuse and physical dependency, interaction with prescription medication, and potential interference with sleep. Check out the YouTube video Bill Nye The Science Guy & Nutrition.

Careful dietary choices can promote health (Taylor, 2015). A fiber-rich diet can reduce the risk of cardiovascular disease and obesity by lowering insulin levels (Ludwig et al., 1999). A diet high in beans, fish, fruits, poultry, vegetables, and whole grains and low in potatoes, processed and red meats, and refined grains can reduce vulnerability to coronary artery disease (Fung et al., 2001). Replace trans and saturated fats with polyunsaturated and monosaturated fats to improve heart health and reduce inflammation. Graphic © Mykola Komarovskyy/Shutterstock.com.

A healthy diet should keep saturated fat under 10% of your daily energy intake, restrict salt to less than 5 g, including 30-45 g of fiber, and two to three servings of fruit and two to three servings of vegetables per day. Fish, especially fish rich in omega-3 fatty acids like salmon, should be eaten one to two times a week. Finally, men should limit alcohol consumption to two standard drinks and women to one standard drink (Vaddadi, 2016). Graphic © Brian A. Jackson/Shutterstock.com.

Hydration

Well-hydrated adults are more likely to experience healthy aging than those who do not consume sufficient fluids. Serum sodium levels rise when fluid intake falls. The National Institutes of Health evaluated three decades of health data from 11,255 adults. Adults with high-normal serum sodium were more likely to experience chronic health conditions, age more quickly, and die earlier than those with medium sodium levels (Dmitrieva et al., 2023).

The study shows that people whose fasting serum sodium exceeds 142 mmol/l have increased risk to be biologically older, develop chronic diseases, and die at a younger age. This threshold can be used in clinical practice to identify people at risk. Since decreased hydration is one of the main factors that elevates serum sodium, the results are consistent with the hypothesis that decreased hydration may accelerate aging.

The authors cautioned that the data are observational, precluding cause-and-effect conclusions.

The Institute of Medicine, now the National Academy of Medicine, set Adequate Intakes for total water of 2.7 liters per day for women and 3.7 liters per day for men, roughly 81% of which typically comes from beverages: about 9 cups (2.2 liters) for women and about 13 cups (3.0 liters) for men (Institute of Medicine, 2005). There are 8 fluid ounces in a cup. Fluids can also come from fruits, juices, and vegetables. These ranges have to be adjusted for exercise, health conditions (e.g., heart failure), and temperature (Agostoni et al., 2010; Dmitrieva et al., 2022).

Cutting Edge Topics in Relaxation

Client Preparation with Respiration Training

This section covers how to assess and correct dysfunctional breathing patterns, the physiological effects of healthy breathing, and practical strategies for teaching breathing skills. Breathing assessment provides a roadmap for training clients to replace dysfunctional breathing with healthy breathing. Correcting breathing fundamentals is critical for heart rate variability biofeedback (HRVB) using paced breathing at the resonance frequency (RF), the breathing rate at which the cardiovascular system responds most powerfully, typically around 6 bpm for adults. Most clients must learn to rely more on their diaphragm, slow their respiration rate (RR), and breathe consistently to produce robust resonance effects.

Shifting to a healthy breathing pattern corrects overbreathing by conserving 85-88% of CO₂ (Khazan, 2021). Preserving CO₂ lowers blood pH, weakens the bond between hemoglobin and oxygen, and increases oxygen delivery to body tissues courtesy of the Bohr effect. Healthy breathing dilates blood vessels, slows heart rate (HR), increases respiratory sinus arrhythmia (RSA), the natural variation in heart rate driven by breathing, and heart rate variability (HRV), and lowers blood pressure (BP). Graphic © fizkes/Shutterstock.com.

This section covers Common Breathing Misconceptions, Healthy Breathing Roadmap, Medical Cautions, Breathing Basics, Physiological Effects of Healthy Breathing, Modalities for Teaching Healthy Breathing, Healthy Breathing Training, and Breathing Practice.

Appreciation

This section draws heavily on Dr. Inna Khazan's clinical experience and extensive writing and presentations on healthy breathing.

Healthy Breathing Training

You can teach healthy breathing as a component of weekly HRVB training sessions. Provide three or more 3-minute segments, some without feedback and pacing, each followed by coaching. Do not progress to HRVB until your client has corrected dysfunctional breathing. Attempting resonance frequency training before establishing good breathing mechanics is like trying to build a house on an unstable foundation.

The red heart rate and blue respirometer tracings are synchronous with an almost 0-degree phase relationship in the screen below. This synchrony between heart rate and breathing is the visual signature of effective training.

Mindful Breathing Awareness

Begin by helping clients develop awareness of their breathing without trying to change it. Use earplugs or fingers in the ears to increase breath awareness by reducing external distractions. The client should experience each breath without struggle, tuning in to the sensations that accompany inhalation and exhalation.

Encourage clients to allow their body to shift from exhalation to inhalation without rushing this process. They should also experience difficult emotions, images, sensations, and thoughts that may arise without judgment (Khazan, 2021). This mindful approach prevents the effortful striving that can activate the sympathetic nervous system and undermine training.

Low-and-Slow Breathing

Robert Fried (1987) recommends shifting breathing to the abdomen and slowing its rate. Clients should take normal-sized inhalations and not emphasize breath depth or volume. They should exhale slowly through the nostrils or pursed lips.

Encourage clients to wear nonrestrictive clothing, loosen their clothing to allow the diaphragm to move freely, and assume a comfortable position like reclining. Invite them to place one hand on the abdomen and the other on the chest for feedback (Khazan, 2021). The hand on the abdomen should rise more than the hand on the chest.

Some clients may find the image of a balloon helpful in shifting from thoracic to abdominal breathing and remembering when the stomach should expand and contract. During inhalation, the stomach expands, inflating the balloon. During exhalation, the stomach contracts, deflating the balloon.

Encourage mindful effortless breathing to prevent larger tidal volumes and faster exhalation that result in overbreathing. Engage passive volition by using words like "allow," "let," and "permit," and avoiding "correct," "effort," "try," and "work." Demonstrate low-and-slow breathing and allow clients several minutes of practice in your clinic.

Help Clients Recover Their Breathing Reflex

The Breathing Reflex

The breathing reflex is a physiological drive to inhale in response to rising CO₂ levels. Clients may override this reflex during overbreathing by inhaling too early, before CO₂ levels rise to the level that would naturally trigger the next breath. This premature inhalation lowers blood CO₂ levels and perpetuates the overbreathing pattern.

This "hijacking" of the breathing reflex may represent an attempt to catch one's breath due to fear of insufficient oxygen or to reduce anxiety (Khazan, 2021). Helping clients wait for the natural urge to breathe can feel counterintuitive to them, but it is essential for restoring healthy breathing chemistry.

Help Clients Correct Acute Overbreathing

Clients who overbreathe are often unaware of their breathing patterns. We need to teach them to "tune in" to their breathing and recognize the signs of overbreathing. They may breathe thoracically, overusing their external intercostal muscles during inhalation instead of relying on the diaphragm.

When clients overbreathe, help them shift to abdominal breathing so that the dome-shaped diaphragm may descend more completely (Khazan, 2021). This shift not only improves ventilation but also reduces the energy cost of breathing and promotes relaxation.

Panic: When Overbreathing is Severe

When a client has difficulty catching their breath, this may trigger panic. The sensations of overbreathing, including lightheadedness, tingling, and chest tightness, can feel terrifying, prompting even faster breathing in a self-reinforcing cycle.

Reassure your client and invite them to hold their breath for 5-20 seconds until the sensations of overbreathing lessen. Monitor their breathing to ensure their practice of low-and-slow breathing with extended exhalations so they do not overbreathe and start another panic cycle (Khazan, 2021).

Troubleshooting

Dizziness or Shortness of Breath

These symptoms are often signs of overbreathing rather than underbreathing. Invite the client to slow their breathing, especially at the start of the exhalation, and to lengthen the exhalation. The instinct to breathe more when dizzy can be counterproductive.

Anxiety or Other Discomfort

Effortful breathing may activate the sympathetic nervous system, producing anxiety rather than the expected calm. Invite the client to switch from "trying to breathe" to "allowing the breath to happen." This subtle shift in approach can make all the difference.

Breathing is Not Relaxing

Reassure the client that this is normal and does not indicate failure. Explain that the primary purpose of breathing training is restoring healthy breathing chemistry and not immediate relaxation (Khazan, 2021). Relaxation often emerges as a secondary benefit once healthy breathing patterns become established, but it is not the goal of each practice session.

Monitor and Reduce Excessive Breathing Effort

Several "red flags" can signal effortful breathing that undermines training. First, accessory muscle (such as trapezius and scalene) SEMG increases when clients try too hard. A trapezius-scalene placement, with active SEMG electrodes located on the upper trapezius and scalene muscles, is particularly sensitive to breathing effort.

A BioGraph Infiniti accessory muscle training screen used to correct clavicular breathing is shown below.

Second, end-tidal CO₂ often declines with effort because trying harder leads to overbreathing. A capnometer can show whether values fall below the normal range of 35-45 mmHg. See the segment from 01:40 to 03:20 in the tracing below.

Third, the respirometer waveform may lose its smoothness when clients try harder. The sinusoidal pattern becomes irregular, with jagged edges and inconsistent timing.

Breathing Practice

Breathing practice between sessions helps generalize breathing skills to everyday life. Clients may benefit from breathing apps and pacers to guide their practice. Encourage them to practice an exercise for 20 minutes daily, log the activity, and discuss it at the start of the next training session. This accountability structure dramatically improves compliance and outcomes.

Also encourage mindful low-and-slow breathing throughout the day, not just during formal practice. Invite your client to observe their breathing several times a day in different settings. When they find themselves overbreathing, they can remind themselves to breathe with less effort.

Encourage Practice with Breathing Apps and Breathing Pacers

You may use computer, tablet, and smartphone apps that provide auditory or visual pacing. Try them out yourself to find the apps that offer the adjustability and ease of use best suited for your clients.

Consider The Institute of HeartMath's Coherence Coach and Thought Technology's EZ-Air Plus for computers. Both programs allow you to customize breathing rates and provide visual feedback that clients can follow during practice.

Popular apps are available for both Android and Apple platforms. The proliferation of breathing apps means you can find options that match your clients' preferences and needs.

Assign practice with breathing pacers and then gradually fade them as clients develop internal timing. The goal is autonomous skill that does not depend on technology. Click on the Alliant link to download these free tracks.

Healthy Breathing Tips

Drs. Erik Peper (1994) and Inna Khazan (2021) have proposed several invaluable breathing suggestions that summarize the key principles of healthy breathing practice.

The BioGraph Infiniti display below shows healthy inhalation and exhalation in which the abdomen gradually expands and contracts. Notice the smooth, rhythmic quality of the waveform.

The BioTrace+/NeXus-10 training screen below was designed to teach effortless breathing. The balloon's inflation and deflation mirror the respiration sensor's rhythmic expansion and contraction, providing an intuitive visual metaphor for clients.

Client Preparation with Heart Rate Variability Biofeedback

Heart rate variability (HRV) is an increasingly important biomarker. Biofeedback aims to exercise the baroreceptor reflex, a mechanism that provides negative feedback control of blood pressure, and the vascular tone rhythm, the rhythmic oscillation in blood vessel diameter that contributes to blood pressure regulation and HRV. By stimulating these systems, HRVB enhances homeostatic regulation, builds regulatory reserve, and strengthens executive functions (Gevirtz, 2021).

Think of it as taking the cardiovascular system to the gym: just as resistance training builds muscle strength and endurance, HRVB builds the cardiovascular system's capacity to respond adaptively to stress.

The field owes much of its clinical foundation to Dr. Paul Lehrer and colleagues (2000, 2013), who published detailed descriptions of their HRVB resonance frequency protocol. These protocols have become the standard reference for clinicians worldwide, providing step-by-step guidance for assessment and training that has been validated across dozens of clinical trials.

Dr. Donald Moss poses a deceptively simple question: "Why do we train?" The answer cuts to the heart of our work. Clinicians providing HRVB training seek to improve their clients' ability to self-regulate, promote health, and enhance quality of life and performance. These goals remain constant whether you are working with a combat veteran managing PTSD, a cardiac patient in rehabilitation, or an Olympic athlete pursuing peak performance.

Core Elements of HRV Biofeedback

The client-practitioner relationship stands as the foundation of all biofeedback and neurofeedback training. HRV biofeedback reaches its full potential when both clinician and client practice mindfulness, fostering the self-awareness and sense of agency that drive lasting change. Effective coaching transforms technical feedback into meaningful learning experiences (Khazan, 2019).

Mindfulness involves "paying attention in a particular way: on purpose, in the present moment, and nonjudgmentally" (Kabat-Zinn, 1994). In the context of HRV training, mindfulness serves as the bridge between physiological feedback and behavioral change. When clients observe their heart rate (HR) patterns without judgment, they become curious scientists of their own physiology rather than frustrated students chasing numbers.

Mindfulness guides the trial-and-error process underlying self-regulation by helping clients draw connections between their actions, internal feedback, and results. A veteran might notice that memories of deployment increase HR irregularity, while focusing on the breath creates smoother, more wavelike patterns. These insights, accumulated through mindful observation, form the foundation of lasting self-regulation skills.

Through this process, clients discover their unique psychophysiological response patterns. One person may find that visualizing ocean waves produces the smoothest HR oscillations, while another achieves the same result through counting or prayer. This individual variability is a feature, not a bug. The feedback helps each client identify which strategies best increase their respiratory sinus arrhythmia (RSA), the rhythmic increase in HR during inhalation and decrease during exhalation, and their overall HRV.

Mindfulness also supports emotional self-regulation by teaching resilience, defined as adapting effectively to new challenges, stressors, threats, and trauma. For a first responder or military service member, resilience means returning to baseline functioning after acute stress. For a chronic pain patient, it means maintaining equilibrium despite ongoing discomfort. The skills are fundamentally the same, even as the contexts differ.

Modern wearable technology extends mindfulness training beyond the clinic. Devices like Lief Therapeutic's wearable signal clients with vibrations when stress responses are detected, enhancing awareness of triggers in everyday situations. This ecological momentary intervention transforms the smartphone notification into a cue for brief self-regulation practice.

Emotional self-regulation encompasses the self-monitoring, initiation, maintenance, and modulation of rewarding and challenging emotions, along with the avoidance and reduction of high levels of negative affect (Bridges et al., 2004). This capacity matters for nearly every clinical population you will encounter, from anxiety disorders to cardiac rehabilitation to performance optimization.

Slow-paced breathing (SPB) involves healthy breathing at or near an individual's unique resonance frequency (RF), the frequency at which the cardiovascular system can be most effectively stimulated. While many practitioners default to 6 breaths per minute (bpm), adult resonance frequencies typically range from 4.5 to 6.5 bpm, and 6.5 to 9.5 bpm in children (Vaschillo et al., 2006; Shaffer et al., 2020), although individual clients may fall outside these ranges. A client whose RF is 5.5 may see little difference in symptom severity or performance gains if trained at 6 bpm.

However, Dr. Khazan (2026) has cautioned that a client whose RF is 3.5 bpm may benefit far less if they breathe at 6.0 bpm. We don't know how much less. HRV biofeedback does not train clients to chase a magic number; rather, it helps each person find their optimal breathing or muscle contraction rate.

Clinicians should not conflate HRVB training with 0.1 Hz training. As Dr. Moss states in the Real Genius episode below, a client's low-frequency peak during RF training will only be at 0.1 Hz when their RF is 6 bpm (6/60 = 0.1 Hz). If their RF is 5 bpm, their peak will be 0.083 Hz (5/60 = 0.083 Hz).

The physiological mechanism is elegant: HRVB stimulates the baroreceptor reflex and vascular tone rhythm simultaneously. When breathing occurs at a client's RF, respiration and heart rate come into phase with the heart rate baroreflex loop, whose delay of roughly 5 s produces a resonance near 0.1 Hz, and this alignment yields maximum HR oscillation and maximum stimulation of vagal pathways. The vascular tone loop resonates far more slowly, near 0.03 Hz, so the two loops are stimulated at different frequencies rather than brought into phase with each other. Over time, this repeated stimulation increases vagal tone and overall HRV, much like repeated weight training increases muscle strength.

Mindful low-and-slow breathing amplifies RSA in a predictable way. The graphic below, adapted from Grossman and Kollai (1993), demonstrates that RSA (shown as the change in HR from inhalation to exhalation) increases as respiration rate approaches 6 bpm. This relationship explains why RF training is so powerful: it positions breathing at the rate that produces maximum HR oscillation.

Dr. Paul Lehrer provides an excellent introduction to these concepts in his resonance frequency breathing and heart rate variability biofeedback presentation from Breathe 2022.

A HRV Biofeedback Koan

Here is a paradox that often confuses new clinicians: during SPB at resonance frequency, your client will show increased peak-to-trough HR differences, higher RMSSD, and elevated low-frequency (LF) power. However, the ultimate goal is not to increase LF power during training sessions. Instead, after weeks of practice, clients should demonstrate increased RMSSD and elevated high-frequency (HF) power when breathing at typical rates without feedback or pacing (Gevirtz, 2021).

Think of it this way: the training itself looks different from the outcome. Athletes lift heavy weights in the gym, but the goal is to perform better on the field without any weights at all. Similarly, HRVB clients breathe slowly with feedback to build cardiovascular fitness that transfers to everyday life without feedback or deliberate slow breathing.

For deeper background, we encourage you to read Lehrer and Gevirtz's (2014) excellent Frontiers in Psychology overview, Heart rate variability: How and why does it work?

🎧 Listen to the Full Chapter Lecture

Medical Cautions

Before beginning HRVB training, clinicians must screen for cardiac abnormalities and compensatory overbreathing that could compromise patient safety. This screening is not optional; it is a fundamental part of responsible practice.

Conduction Abnormalities

Examine ECG morphology for evidence of arrhythmias, ischemia, and prolonged QT intervals (Drew et al., 2004). When abnormalities appear, encourage clients to consult with their physicians before proceeding. Training should only continue if the physician considers it appropriate.

Screening for arrhythmias should inform your data cleaning and interpretation of HRV metrics. Providers must take special care in analyzing contaminated epochs, discarding them in extreme cases. Arrhythmias that cause software to miss beats or calculate extra beats will distort HRV metrics, especially wearable apps that perform limited or no artifacting.

Atrial fibrillation, the most common cardiac arrhythmia, involves rapid and irregular contraction of the two upper atrial chambers. On the ECG, you will see an absence of distinct P waves and an irregularly irregular ventricular response. Clients with atrial fibrillation present unique challenges for HRV measurement because the arrhythmia itself produces extreme variability unrelated to autonomic function.

Ischemia, insufficient blood supply to cardiac tissue, produces characteristic depression of the ST segment on the ECG. The ST segment represents the period between ventricular depolarization and repolarization. Compare the normal ST segment in the left panel with the depressed segment indicating subendocardial ischemia in the right panel. If you observe ST depression during a training session, stop immediately and refer the client for medical evaluation.

The QT interval signals the depolarization and repolarization of the ventricles. This interval, measured from the beginning of the Q wave to the end of the T wave, reflects the total time required for the ventricles to complete one electrical cycle.

A prolonged QT interval carries significant clinical risk. This finding is associated with increased vulnerability to ventricular tachyarrhythmias, which can result in cardiac arrest and sudden death. Certain medications, electrolyte imbalances, and genetic conditions can cause QT prolongation. If you identify a prolonged QT interval, the client must be evaluated by a cardiologist before any biofeedback training that affects autonomic tone.

Compensatory Overbreathing

SPB may be medically contraindicated when altered breathing patterns could be hazardous for clients suffering from diabetes (Kitabchi et al., 2009) or kidney disease (Kim et al., 2021) that produce metabolic acidosis, excess acid in the body fluid. In these conditions, the body relies on specific respiratory patterns to maintain acid-base balance, making interventions that alter breathing potentially dangerous to the client's physiological homeostasis.

Respiratory Acidosis

Common respiratory acidosis causes include chronic obstructive pulmonary disease (COPD), asthma, pneumonia, and neuromuscular disorders that affect breathing muscles. These conditions impair the lungs' ability to eliminate carbon dioxide effectively, leading to respiratory acidosis. Interventions that further alter breathing patterns could exacerbate these underlying physiological imbalances.

In metabolic acidosis, patients may breathe rapidly to protect acid-base balance. Rapid breathing helps to expel carbon dioxide (CO2) from the body, which in turn can increase the pH and counteract the acidosis. Respiratory acidosis is different: there the lungs cannot clear CO2 adequately in the first place, and the kidneys, not the lungs, provide the compensation.

This compensatory hyperventilation represents a crucial physiological adaptation that maintains homeostasis. Interventions that interfere with this compensatory mechanism could compromise the patient's health and safety. SPC provides a safe alternative that can improve heart rate variability and autonomic balance without disrupting these essential respiratory compensatory mechanisms.

Clinical Tips When You Start HRV Biofeedback Training

Successful HRVB training depends on numerous clinical elements working in concert. These include modeling appropriate breathing and emotional states, building a strong therapeutic relationship, cultivating passive volition, selecting appropriate monitoring equipment and displays, teaching alternatives like slow-paced contraction, detecting and addressing excessive effort, using engaging games and apps, implementing effective pacing strategies, optimizing resting HR, and integrating emotional self-regulation techniques.

Modeling

Clinicians are always on stage. Your breathing pattern, posture, and emotional state communicate more than your words. Model low-and-slow breathing and rewarding emotions throughout each session. If you are anxious, rushed, or breathing rapidly, your client will unconsciously match your state.

This phenomenon, known as physiological entrainment, works both for and against you. Use it intentionally by embodying the calm, rhythmic presence you want your client to develop.

Relationship

A warm and supportive relationship with your client is the foundation for successful biofeedback training (Taub & School, 1978). From a polyvagal theory perspective, the therapeutic relationship creates a neuroception of safety that enables the ventral vagal complex to come online. In plain language: clients cannot learn to activate their parasympathetic nervous system while feeling unsafe. Your relationship provides the secure base from which they can explore alternatives to fight-or-flight, freezing, or parasympathetic withdrawal.

Passive Volition

Encourage an attitude of passive volition, characterized by allowing rather than forcing, effortlessness rather than striving. Clients often describe this state as "my body breathing itself." This passive attitude is crucial because active effort triggers sympathetic nervous system (SNS) activation, which reduces vagal tone and promotes overbreathing. The harder clients try, the worse their results become. Help them understand that HRV biofeedback rewards letting go, not pushing harder.

Monitoring HRV

Your choice of sensor affects both accuracy and client comfort. For clinical work, consider an ECG sensor with wrist placement or a photoplethysmograph (PPG) sensor on an earlobe or finger. PPG sensors, which measure blood volume changes optically, trade some accuracy for ease of application. This tradeoff is acceptable for most clinical training.

However, certain conditions require ECG monitoring. When significant vasoconstriction occurs due to cold ambient temperature, stress, or physical activity, PPG signals degrade substantially. Movement artifacts also affect PPG more than ECG. If your client will be standing, moving, or training in challenging conditions, ECG provides more reliable data (Constant et al., 1999; Hemon & Phillips, 2016; Jan et al., 2019; Medeiros et al., 2011).

Selecting an Effective Display

The feedback display shapes what clients learn. Provide an HRV training screen showing both respirometer and instantaneous HR waveforms. Analog displays convey incredibly detailed and intuitive information that digital numbers cannot match. Encourage your client to focus on increasing peak-to-trough swings in HR during each breathing cycle (Lehrer et al., 2013; Lehrer & Gevirtz, 2014). When they see their HR rise with inhalation and fall with exhalation, the abstract concept of RSA becomes viscerally real.

While client preference and success should guide your selection, consider starting with feedback of LF power and peak-to-trough differences. These metrics respond quickly to breathing changes and provide clear, motivating feedback.

Dr. Inna Khazan demonstrates how slow-paced and normal breathing change low- and high-frequency power in this video. Notice how the spectral distribution shifts dramatically when breathing slows to resonance frequency.

The BioGraph Infiniti screen shown below is designed to increase the percentage of power in the LF band. This three-dimensional display shows the dynamic change in HRV amplitude distribution as a client breathes effortlessly and cultivates positive emotion. Watching power concentrate at 0.1 Hz provides compelling feedback that motivates continued practice.

Some clients prefer displays showing synchrony, the alignment of peaks and troughs between respirometer and instantaneous HR signals. Synchrony matters because it amplifies the resonance effects of SPB (Vaschillo et al., 2002). When respiration and HR oscillate together in phase, the baroreceptor reflex receives maximum stimulation. The NeXus-10 BioTrace+ screen below displays synchrony between respiration and HR. The flower opens as alignment increases, providing intuitive visual feedback.

Add Slow-Paced Contraction to Your Training Toolkit

Slow-paced contraction (SPC) offers an alternative pathway to resonance frequency stimulation. Some clients find SPB challenging, whether due to anxiety, chronic pain, respiratory conditions, or a lifetime of dysfunctional breathing. Others have medical contraindications for deliberate breathing modification, such as kidney disease with metabolic acidosis, where slowing respiration could dangerously alter the acid-base balance.

SPC may benefit clients who breathe dysfunctionally and cannot slow their breathing to the adult RF range of 4.5 to 6.5 bpm without significant distress. By focusing on muscle contraction rather than breathing, these clients can access resonance frequency benefits while their breathing naturally entrains to the rhythm.

In SPC exercises, clients briefly contract and relax skeletal muscles at the same 4.5 to 6.5 cycles per minute (cpm) rates used in breathing exercises while allowing their respiration to occur naturally. The muscles involved are the wrists and ankles, or wrists, core, and ankles together.

Hypothesized Mechanism

Like SPB, SPC generates large HR oscillations and stimulates the baroreceptor reflex to increase HRV. The hypothesized mechanism, a muscle pump that increases venous return and stroke volume to produce arterial pressure fluctuations differs, but the outcome is equivalent. Although the muscle pump increases HR oscillations, these changes are not RSA because they are driven by wrist-core-and-ankle contraction instead of breathing.

HRV Sensors

Choose an ECG sensor, like Thought Technology Ltd.'s EKG-Flex/Pro.

Use a chest or lower torso placement. A chest placement is one of several options for male clients.

A lower torso placement preserves client modesty and reduces EMG contamination of the ECG signal.

You can place an Optimal HRV Reader, which uses a PPG sensor, on your client's arm.

You may also use a PPG earlobe sensor like the Institute of HeartMath's Inner Balance.

EMG Sensor

Place an EMG sensor like Thought Technology Ltd.'s Myoscan over the forearm extensors and flexors to measure the rate of SPC.

Position

Clients should recline with their ankles crossed and feet supported by a footrest or separate chair. Although the original Vaschillo protocol only contracted the wrists and ankles with legs uncrossed, we have observed greater HR oscillations with wrist, core, and crossed-ankle contractions.

Muscle Contraction Mechanics

Instruct your clients to gently simultaneously contract their wrists, core, and ankles. If you are combining SPB with SPC, only contract the wrists and ankles. Your clients should use about 25% of their maximum effort. They should feel as if their muscles are contracting themselves, rather than their forcing the movement.

Contraction and Relaxation

They can hold each gentle contraction for 3 seconds.

Display

We repurposed this BioGraph Infiniti display for SPC training. Clients start contracting their muscles 1.5 s before and end 1.5 s after each cycle's peak. We use the verbal prompt, "contract," to reinforce the visual display.

The video below demonstrates 6-cpm SPC. Observe the recruitment of core muscles, including the rectus abdominis, during the contraction phase.

This second video shows 6-cpm SPC with an interesting finding: the model was not given breathing instructions, yet the SPC naturally entrained breathing rhythm. This entrainment effect makes SPC particularly valuable for clients who struggle with deliberate breath control.

Maximum-Minimum HR for each cycle indexes HRV. The peak frequency indicates the HRV frequency with greatest power. In the screen captures below, SPC stimulated the baroreceptor reflex at the intended frequency: 0.2 Hz for 12 cpm and 0.1 Hz for 6 cpm.

This BioGraph Infiniti display shows 12-cpm SPC. At the top right, the Maximum-Minimum HR for each cycle is 5 bpm. At the left, the peak frequency is 0.2 Hz, exactly as expected from the 12-cpm rate.

Compare this to 6-cpm SPC. The Maximum-Minimum HR for each cycle is now 30 bpm, six times greater than at 12 cpm. The peak frequency has shifted to 0.1 Hz. This dramatic increase in HR oscillations demonstrates why resonance frequency training is so powerful.

Although the original Vaschillo protocol contracted only wrists and ankles with legs uncrossed, clinical experience has shown greater RSA using wrist, core, and crossed-ankle contraction as demonstrated below.

Combine Slow-Paced Breathing With Slow-Paced Contraction

Dr. Inna Khazan combines SPB with SPC when her clients struggle to learn SPB. SPC can serve as a powerful pacing cue for their breathing rhythm, and a model of the effortlessness we encourage. Matt Bennett, Optimal HRV co-founder, recommends combining SPB + SPC to increase HRV for clients who have mastered SPB. He finds that their HR Max - HR Min and low-frequency values are greater when they combine SPC with SPB. They can see improved results after training trials using the Optimal HRV application.

Clinicians who treat Postural Orthostatic Tachycardia Syndrome (POTS), which is characterized by an excessive increase in heart rate and dizziness when standing, report that their clients have minimal HRV and require the combined approach to achieve clinical gains.

Muscle Contraction

When combining these techniques, limit contraction to the wrists and ankles to permit the abdomen to expand and the diaphragm to descend.

Coordinating Breathing with Wrist-Ankle Contraction

Using the BioGraph Infiniti display for combined training, clients start gently inhaling as the pacing ball ascends and stop inhaling at the peak. They begin exhaling after the pause until the pacer reaches the bottom right portion of the display.

The easiest way to synchronize muscle contraction with breathing is to gently contract the wrists and ankles during inhalation and relax these muscles during exhalation. Alternately, clients can begin contracting their muscles 1.5 s before the peak and end 1.5 s after each cycle's peak. We use the verbal prompt, "contract," to reinforce the visual display. The video below demonstrates combined 6-cpm SPB and SPC.

Monitoring Excessive Effort

Excessive effort, or active volition, during HRVB training undermines the very goals clients are trying to achieve. When clients try too hard, they can produce vagal withdrawal, shown by increased very-low-frequency (VLF) power, increase SNS activation, indicated by increased HR and skin conductance (SC), and reduced finger temperature, and promote overbreathing, which can expel too much CO₂, measured by a capnometer. The paradox of biofeedback is that striving sabotages success. Your role as clinician is to detect effort early and redirect clients toward the passive, allowing attitude that produces optimal results.

Fortunately, effort leaves clear physiological signatures that you can monitor in real time. The primary excessive effort indicators are respirometer waveform irregularities, and changes in HR, VLF power, and HRV metrics like the RMSSD, and SC, temperature, accessory muscle SEMG activity, and capnometer readings.

Respirometer

Breathing effort disrupts the smooth, wavelike pattern that characterizes effortless respiration. Look for inflection points, sudden changes in the slope of the breathing waveform that indicate muscular forcing. A smooth sine wave suggests flow; a jagged waveform with sharp corners suggests struggle.

HR and HRV

When training effort produces vagal withdrawal, a reduction of parasympathetic activity, HR may increase, time-domain metrics like the RMSSD may decrease, and VLF band power may rise. Do not read increased VLF power as an index of sympathetic activation. VLF appears to be generated within the heart itself, by afferent sensory neurons feeding the intrinsic cardiac nervous system, with additional contributions from physical activity, thermoregulation, the renin-angiotensin system, and endothelial factors; sympathetic activity modulates the amplitude and frequency of these oscillations but sympathetic blockade does not abolish VLF power (Shaffer & Ginsberg, 2017). It is the HF band that sympathetic activity is too slow to generate, since the sympathetic system does not appear to produce rhythms much above 0.1 Hz (Shaffer et al., 2014).

In the FFT spectral plot below, VLF power appears in gray. If you see rising VLF during training, consider whether your client is working too hard.

Skin Conductance and Finger Temperature

With sufficient HRVB training effort, sympathetic activation may follow vagal withdrawal. Depending on your client's unique response stereotypy, skin conductance may increase due to increased eccrine sweat gland activity and/or finger temperature may decrease due to arteriole constriction.

Accessory Muscle SEMG

Surface electromyography can detect overuse of breathing accessory muscles, including the sternocleidomastoid, scalenes, pectoralis major and minor, serratus anterior, and latissimus dorsi. These muscles assist respiration during exercise or respiratory distress but should remain relatively quiet during relaxed diaphragmatic breathing. A trapezius-scalene placement, with active SEMG electrodes on the upper trapezius and scalene muscles, provides a window into respiratory effort. Activity above 2 microvolts during slow breathing suggests excessive effort.

This BioGraph Infiniti screen provides respiratory and SEMG biofeedback simultaneously, teaching rhythmic breathing while maintaining relaxed accessory muscles. Note the elevated SEMG activity during clavicular breathing, which relies heavily on accessory muscles rather than the diaphragm.

Capnometer

Excessive breathing effort that expels too much carbon dioxide decreases end-tidal CO₂ readings. A capnometer monitors CO₂ concentration in exhaled air by measuring infrared light absorption. When clients overbreathe, their end-tidal CO₂ drops below the normal range of 35-45 mmHg (or torr, named after Torricelli, representing the unit of atmospheric pressure equal to 1 millimeter of mercury). In the tracing below, note the disrupted capnometer waveform after 1:40, indicating a period of overbreathing.

Engaging Games and Apps

Once your client has mastered SPB, games can transform practice from duty into pleasure. The gamification of HRV biofeedback serves two purposes: it motivates sustained practice and it tests the robustness of self-regulation skills under challenge. Biofeedback software allows clients to increase game difficulty progressively, developing the capacity to maintain regulation even when challenged. This graduated exposure is crucial for transferring skills to the unpredictable demands of everyday life.

The market offers diverse options for HRV biofeedback games and apps. Professional software packages like Zukor's Drive and Zukor's Sport provide engaging visual feedback for clinic use. The HeartMath Garden Game and BioGraph Infiniti offer additional clinic-based options. For home practice, mobile apps including Inner Balance, Elite HRV, HRV4 Training, and Camera HRV enable convenient daily training.

Pacing Displays

Pacers guide breathing and slow-paced muscle tension using animation and sound. Software may integrate a pacer directly into an HRVB display or provide it as a standalone tool. The training strategy is straightforward: assign practice with breathing pacers initially, then gradually fade them as clients internalize the rhythm. The goal is autonomous self-regulation, not dependence on external pacing.

Computer, tablet, and smartphone apps offer various pacing options with different features. Try several to find apps that offer the adjustability and ease of use that best match your clients' needs. For computer-based pacing, Coherence Coach and EZ-Air Plus provide reliable options.

These mobile apps are available for both Android and Apple platforms, making practice accessible wherever clients go.

Auditory Pacing

Some clients prefer auditory rather than visual pacing, finding it easier to close their eyes and follow sound cues. The Alliant International University link provides downloadable auditory pacing resources at various breathing rates.

Stopwatch Pacer

For slow-paced contraction training, a simple stopwatch app that continuously loops can serve as an effective pacer. For 6 contractions per minute, select 10 seconds with no pause. Instruct your client to simultaneously contract their hands and feet for the first 3 seconds of each cycle, then relax for the remaining 7 seconds. This low-tech solution works surprisingly well.

Lifestyle Choices

Unhealthy choices can erode HRV, while healthy ones help to preserve it. These are the levers you actually get to pull.

This section examines the daily behaviors and exposures that shape autonomic function, beginning with how clients move and what they carry. Physical activity stands out as the single behavior most reliably tied to better parasympathetic and global HRV, while weight loss and reduced sitting time each ease the sympathetic burden that suppresses vagal tone. Recovery matters just as much, so we examine how adequate sleep and proper hydration protect the autonomic gains that daytime habits set in motion.

From there we turn to the cardiovascular and psychological systems that HRV biofeedback already targets, considering how blood pressure reduction restores baroreflex sensitivity and how stress management lowers the allostatic load that erodes HRV over months and years. The remaining topics widen the frame to relationships, environment, and exposures, exploring how compassion practice trains the vagus, how time in green space and strong community and social connection support parasympathetic regulation, and how acute stressors such as alcohol, illness, and overtraining temporarily depress HRV. We close with drug effects on HRV, because a complete picture of any client's prescription and social drug use is essential for interpreting baseline and training values.

Physical Activity

Physical activity is the only behavior that, when analyzed in isolation, was associated with better PNS and global HRV in adults (Saraiva et al., 2026).

At the population level, physical activity shows a moderate correlation with resting heart rate (r = 0.30) but only a weak correlation with the RMSSD (r = 0.21) (Altini & Plews, 2021). This is another reason not to judge your fitness by your RMSSD: it may not budge even when your cardiovascular fitness is clearly improving.

Weight Loss

Body mass index (BMI), which is weight divided by height squared, exerts a small but consistent influence on HRV. The obese category showed the highest resting heart rate (62 ± 8 bpm) and lowest RMSSD (56 ± 30 ms) compared to the normal-weight category (56 ± 8 bpm, 69 ± 35 ms; Altini & Plews, 2021).

Obesity-related insulin resistance produces compensatory elevations in circulating insulin. Insulin acts directly on hypothalamic neurons to stimulate sympathetic centers in the brainstem (Guarino et al., 2017).

The good news: BMI is at least partially modifiable, and reductions in adiposity through lifestyle changes can restore the vagal brake and increase HF power and the RMSSD (Kalil & Haynes, 2012).

Sleep

The CDC's sleep grades for 2024 have been released, and the marks are mixed at best (Ng et al., 2026). Nearly a third of adults, 30.5%, clocked fewer than seven hours of sleep in a typical 24-hour period, falling short of what the American Academy of Sleep Medicine recommends for healthy functioning.

Just over half of adults (54.8%) actually woke up feeling well-rested most days, meaning the other half started their mornings already behind.

An estimated 18.1% struggled to stay asleep once they fell asleep. The data tell a story of a country that knows it should sleep more, knows it should sleep better, and routinely does neither.

Gonzales et al. (2023) found that adequate sleep duration of approximately 7 hours was related to greater HRV in middle-aged women. Once adequate, restorative sleep is achieved, further gains from additional hours become marginal. Protect the sleep you have.

Blood Pressure Reduction

Baroreflex gain is how strongly the baroreflex adjusts heart rate in response to changes in blood pressure. Baroreflex gain varies over time, differs between daytime and nighttime, and is modulated by age, posture, physical activity, and other reflexes (Parati et al., 2009).

The contribution of blood pressure control to HRV is not fixed but dynamically modulated across physiological states and across the lifespan.

Interventions that restore baroreflex function, like antihypertensives (Ylitalo et al., 1999) or resonance frequency biofeedback (Vaschillo et al., 2006), can improve baroreflex sensitivity (BRS) and HRV.

Stress Management

Stress management increases HRV through the coordinated restoration of prefrontal inhibitory control, baroreflex sensitivity, vagal efferent activity, and reduced allostatic burden.

Stress management reduces allostatic load, the cumulative physiological toll of chronic stress adaptation, which itself suppresses HRV over time (Thayer & Sternberg, 2006).

By dampening HPA axis hyperactivity, reducing inflammatory cytokine levels, and normalizing sympathoadrenal output, effective stress management enhances parasympathetic cardiac regulation.

HRV biofeedback at the resonance frequency produces the largest and most consistent HRV increases, followed by structured slow-paced breathing, aerobic exercise training, mindfulness-based practices, and cognitive-behavioral approaches.

The most effective stress management strategy for increasing HRV is one that addresses the specific autonomic dysregulation present in the individual while incorporating a component of direct physiological training (Shaffer & Ginsberg, 2017).

Hydration

Dehydration reduces blood plasma volume, which in turn can lower baroreflex sensitivity and suppress vagal tone.

Buchheit et al. (2009) showed a large correlation (r = 0.85) between relative changes in RMSSD and changes in blood plasma volume during recovery from exercise.

Replace Sitting with Movement

Reducing sedentary behavior improves HRV. Nakayama et al. (2021) found that patients who decreased their sitting time over 6 months showed increased parasympathetic HRV.

The mechanism may involve reductions in body adiposity and inflammatory markers, particularly when sedentary time is replaced with moderate-intensity physical activity (Pinto et al., 2023). The prescription is simple: move more, sit less, and break up long bouts of stillness.

At the office, take large movement breaks. Stretch or move every 20 minutes (Peper & Gibney, 2005).

Compassion Trains the Vagus

In the landmark ReSource Project, a 9-month longitudinal mental training study, training modules on compassion, loving-kindness, and contemplative dyadic exercises improved participants' ability to voluntarily upregulate high-frequency HRV during biofeedback beyond what changes in breathing rate could explain (Bornemann et al., 2019).

Compassion meditation may enhance self-regulatory capacity rather than directly boosting resting RMSSD, aligning with the broader theme that autonomic flexibility, not absolute HRV magnitude, is the meaningful outcome.

Green Space Exposure

Acute exposure to green spaces produces reliable short-term increases in parasympathetic HRV indices.

The strongest and most consistent findings emerge from controlled crossover designs comparing forest walking to urban walking. supporting autonomic health (Brown et al., 2013; Tsunetsugu et al., 2010).

The magnitude of these acute HRV effects is generally moderate and smaller than those produced by targeted physiological interventions such as HRV biofeedback (Lehrer & Gevirtz, 2014). However, the accessibility and scalability of green space exposure make it a promising population-level strategy for supporting autonomic health.

Community and Social Connection

Social isolation and loneliness have been associated with reduced HRV and heightened sympathetic activation, consistent with the broader literature linking social disconnection to cardiovascular risk.

Polyvagal theory (Porges, 2007) proposes that the ventral vagal complex supports social engagement and that perceived social safety enhances PNS regulation.

Living in an environment where one can thrive, maintaining community ties, and cultivating supportive relationships contribute to the broader context that allows HRV to reflect well-regulated autonomic function.

Acute Stressors

Three acute stressors, alcohol, illness, and excessive physical training can raise HR and lower HRV.

Drug Effects on HRV

Providers should obtain a complete list of a client's prescription and social drugs to better understand baseline and training HRV values.

HRV Biofeedback Training

Overview

Clients often experience measurable improvements during their very first training session, demonstrating increased RSA and improved HRV time- and frequency-domain measurements. After approximately four 30-minute sessions, many clients have corrected dysfunctional breathing patterns and show increased vagal tone and HRV. However, achieving maximum health and performance gains typically requires extended training of ten or more sessions combined with consistent home practice (Lagos et al., 2011).

This section covers the essential elements of training: session structure, resting baseline measurements, selecting initial respiration rates, introducing training to clients, recognizing success and difficulty indicators, reviewing training segments, promoting mindful breathing, conducting session reviews, comparing pre- and post-session values, key training elements, and determining how many sessions are needed.

Session Structure

A well-organized session flows through three phases: pre-baseline measurement, active training, and post-baseline measurement. This structure serves both clinical and motivational purposes. By bracketing training with baseline measurements, you create clear before-and-after comparisons that document learning and motivate continued practice.

Resting Pre- and Post-Baseline Measurements

Resting baselines capture your clients' psychophysiological activity without feedback or paced breathing. Instructions should be minimal and neutral: "Please sit quietly and breathe normally for the next few minutes." Depending on your clinical goals, you might monitor HRV, breathing parameters including depth, pattern, and rate, autonomic indicators such as skin conductance and temperature, blood pressure, and end-tidal CO₂.

The comparison between pre-baseline and post-baseline values within a single session demonstrates within-session learning. Even more valuable is tracking pre-baseline changes across sessions, which reveals the combined effect of clinic training and home practice. A client whose pre-baseline HRV improves from session to session is integrating the skills into daily life.

During baselines, clients breathe at typical rates of approximately 12-16 bpm, so do not expect increases in LF power. Instead, look for increased HF power, improved HRV time-domain metrics such as RMSSD, elevated hand temperature, and reduced skin conductance level. These changes indicate genuine improvements in vagal tone and autonomic regulation.

How to Select a Starting Respiration Rate

Select an initial respiration rate for the animated pacing display based on your client's determined resonance frequency. However, shaping is crucial to client motivation and success. Rather than jumping immediately to the RF, choose a starting respiration rate within 1 or 2 breaths per minute of the client's baseline mean. This ensures early success, building confidence before gradually shifting toward the target rate.

Training Introduction

How you introduce training shapes your client's understanding and approach. Sample instructions that have proven effective include the following:

A healthy heart is not a metronome. As you inhale, your HR speeds, and as you exhale, your HR slows. This rhythmic speeding and slowing of your heart produces heart rate variability, which is vital to your health, performance, and resilience against stressors. The purpose of heart rate variability biofeedback training is to teach you to increase the healthy speeding and slowing of your heart by breathing effortlessly at the rate that is best for you and by increasing your ability to experience positive emotions like feelings of appreciation and gratitude.

Adopt a passive attitude in which you trust your body to breathe itself. Allow your attention to settle on your waist. Let your exhalation continue until your body initiates your next breath. Your inhalations should be no deeper than if you were smelling a flower. Allow your breathing to follow the yellow ball effortlessly.

Allow your stomach to gradually plop out as you inhale and then slowly draw inward as you exhale. As you practice, we will adjust the speed of the pacing display. Let it guide your inhalation and exhalation. Allow your stomach to gradually plop out as you inhale and then slowly draw inward as you exhale.

The computer can help you learn slow, effortless breathing. The pink tracing shows your HR, while the violet tracing shows the movement of the sensor around your stomach. As you gradually learn low-and-slow breathing, the two tracings should resemble smooth, repeating ocean waves.

After providing instructions, start recording data for a 3-minute training segment. At the end of each segment, engage the client in reflection: "How was the speed of the pacing display? Should we change it? Should we adjust the inhalation and exhalation lengths? What did you experience as you practiced breathing effortlessly?" These questions promote mindfulness and collaborative adjustment.

Training Success Indicators

Several signs indicate that training is proceeding well. Look for smooth, wavelike tracings in both respiration and HR signals. The peaks and troughs of these waveforms should align, indicating synchrony. Peak-to-trough HR differences should increase as the session progresses. The client should appear relaxed and report a sense of calm or ease.

Training Difficulty Indicators

Equally important is recognizing when clients struggle. Warning signs include jagged, irregular waveforms with frequent inflection points. Misalignment between respiration and HR tracings suggests poor synchrony. Decreasing or stagnant peak-to-trough differences indicate the client may be working too hard or breathing at the wrong rate. Physical signs of tension or client reports of frustration or discomfort warrant immediate attention.

Training Segment Review

After each 3-minute segment, fit the entire recording on one screen and review it collaboratively with your client. If they succeeded, point out specific moments of success: "See how smooth your breathing became here? And notice how your HR waveform synchronized with your breathing signal in this section." Concrete positive feedback builds confidence and clarifies what success looks and feels like.

Promote Mindful Breathing

Before starting the next segment, engage the client's curiosity about their own physiology. Ask questions like: "What were you doing when the display became wavelike and regular? What happened when the display became more jagged and irregular?" If accessory SEMG exceeded 2 microvolts, show this on the display, ask whether they noticed heightened breathing effort, and encourage them to "let your shoulders relax and allow yourself to breathe."

Reassure clients that choppy tracings are normal at the start of training. The waveforms will gradually become more wavelike as breathing becomes more rhythmic and regular. Rather than overwhelming clients with corrections, ask them to experiment with one or two changes at a time. For example: "Effortless breathing is rhythmic like ocean waves. Allow your stomach to gently expand and contract as you follow the pacing display."

Session Review

After your client has completed six 3-minute training segments, conduct a 3-minute post-baseline recording without feedback. Following this final baseline, ask your client how they felt and what they learned during the session. Display the entire session on one screen, highlighting moments of success and areas that need continued work. This comprehensive review helps clients understand their trajectory and sets expectations for future sessions.

Comparing Pre- and Post-Session Values

Without pacing or feedback, your client will breathe at typical rates during both baselines. The meaningful comparisons between pre- and post-baseline involve metrics that reflect vagal tone at normal breathing rates: HF power, RMSSD, and hand temperature should increase, while skin conductance level should decrease.

The graphic below shows HF power (in blue) during a pre-training baseline, HRVB training, and a post-training baseline. On the y-axis, power in each band is displayed in absolute units. HF power increases from approximately 100 ms² during the pre-training baseline to approximately 300 ms² during the post-training baseline. This threefold increase indicates meaningfully enhanced vagal tone.

Also note the greater LF power concentration in the post-training baseline compared with pre-training, even though the client breathed at typical rates in both baselines. This carryover effect demonstrates that resonance frequency training benefits persist beyond the training itself. These spectral plots were generously provided by Dr. Inna Khazan.

HRV Biofeedback Training Elements

Effective training integrates multiple elements working together. These include appropriate sensor selection, engaging feedback displays, individualized breathing rates based on resonance frequency assessment, a supportive therapeutic relationship, passive volition and effortlessness, mindful attention to body sensations, integration of positive emotion, and consistent home practice.

How Many HRVB Sessions Are Required?

Many clients begin to breathe more effortlessly and show increased HRV during their very first training session. However, there is typically a several-week lag between increased HRV during training and improved health or performance in daily life. Clients require this time to consolidate their learning and transfer enhanced skills to the diverse settings of their lives.

Practice is the bridge between the clinic and everyday life. Without consistent home practice, even excellent in-clinic performance may not translate to real-world benefits.

The physiological changes follow a predictable timeline. Increased RSA immediately exercises the baroreflex without necessarily changing baseline vagal tone or improving blood pressure regulation. Those deeper adaptations require months of consistent practice (Gevirtz et al., 2016; Lagos et al., 2011). Think of it like exercise: a single workout feels good, but cardiovascular fitness develops over months of training.

Practice Assignments

Home practice transforms clinic learning into lasting change. Encourage clients to measure their HRV while breathing at typical rates immediately after waking, when circadian influences are relatively stable. They can send weekly reports showing trends in their HRV, and products like Optimal HRV automate data sharing between clients and clinicians.

The standard recommendation is 20 minutes of daily practice with HRV monitoring. After each practice session, clients can complete an online diary and share their interbeat interval data with you. Khazan (2013) provides excellent practice logs in The Clinical Handbook of Biofeedback that you can adapt for your clinical needs.

Reality often differs from recommendations. Some clients will practice diligently; others will not. You may have to settle for 10 minutes once a day or practice "as needed." Interestingly, Lehrer et al. (2020) concluded that the frequency and length of home practice did not significantly impact effect size. The practice of resonance frequency breathing as needed may have produced most of the observed gains (p. 125). This finding suggests that even brief, strategically-timed practice can be valuable.

Following Dr. Gevirtz's recommendation, include starting and ending hand temperatures in practice logs, since successful HRVB practice may produce peripheral warming as increased CO2 in the bloodstream promotes nitric oxide release and vasodilation.

Effective practice assignment requires four steps. First, explain the purpose of the exercise so clients understand why it matters. Second, demonstrate the skill in the clinic so they can see correct technique. Third, confirm that they can correctly perform it before leaving. Fourth, secure their agreement to practice.

To build a collaborative relationship and empower your clients, encourage them to find ways to improve exercises or develop alternatives that work better for their lives.

Overview

This section addresses practice in diverse settings, aerobic activity, HR monitoring, HRV monitoring, emotional self-regulation techniques, home HRV practice equipment, advanced HRV assessment, and finger temperature monitoring.

Practice in Diverse Settings

Encourage clients to practice resonance frequency breathing during everyday activities in diverse settings including commuting, work, and home. This varied practice promotes generalization, the ability to apply skills across different contexts. A veteran who practices only in a quiet clinic may struggle to access those skills during a stressful meeting at work. Practice in multiple environments builds robust, flexible self-regulation.

Aerobic Activity

Assign 20 minutes daily of aerobic activity, particularly for sedentary clients. Aerobic exercise produces cardiovascular adaptations that complement HRV biofeedback: it lowers resting HR and raises baseline HRV. These effects are additive with HRVB training, creating synergies that neither intervention achieves alone.

Monitor HR

Invite clients to monitor their HR during daily activities and emotional states using wearable devices. This practice increases mindfulness of stressors and physiological responses to challenges. When a client notices that checking email raises their HR by 15 bpm, they gain insight that motivates behavior change. Self-monitoring transforms abstract concepts into personal discoveries.

Monitor HRV

Apps like Elite HRV and Optimal HRV enable clients to take HRV snapshots with built-in artifact correction. These brief measurements, taken consistently over time, reveal patterns and progress that motivate continued practice. The data also provides valuable clinical information about how clients respond to life stressors.

Emotional Self-Regulation Practice

Emotional self-regulation practice complements breathing training by addressing the psychological dimension of stress response. These techniques may reduce parasympathetic withdrawal, cultivate the tend-and-befriend response, and increase resilience. For many clients, emotional regulation proves as important as breathing technique.

The Institute of HeartMath's Lock-In Technique provides a structured approach to emotional self-regulation. Instructions for the technique are as follows:

Try to focus your attention on the area around your heart. Maintain your heart focus and, while breathing, imagine that your breath is flowing in and out through the heart area. Breathe casually, just a little deeper than normal.

Now try to recall a positive emotion or feeling that makes you relaxed and comfortable. Find a positive feeling like appreciation, care, joy, kindness, or compassion. You can recall a time you felt appreciation or care. This could be the appreciation or care you feel towards a special person, a pet, a place you enjoy, or an activity that was fun for you.

If you cannot feel anything, that is okay. Just try to find a sincere attitude of appreciation or care. Continue to think of this positive feeling or emotion.

Home HRV Practice

Portable HRV biofeedback devices bring the training experience home. The Institute of HeartMath's Inner Balance and similar devices allow personal training whenever clients choose, removing the constraint of clinic-only practice. This accessibility dramatically increases potential practice time and supports skill maintenance after formal treatment ends.

Advanced HRV Assessment

For clients who want detailed progress tracking, the Institute of HeartMath's emWave Pro Plus provides comprehensive HRV assessment using an automated deep breathing protocol. The software reports commonly used HRV metrics referenced to age-related norms, allowing clients to see how they compare to healthy populations and track their improvement over time.

The emWave Pro Plus also provides resting metrics for training sessions ranging from 1 to 99 minutes, offering flexibility for different clinical protocols and client preferences.

Monitor Finger Temperature

Encourage your clients to monitor their hand temperature using inexpensive alcohol thermometers to see whether their practice produced warming or cooling. Hand temperature provides a simple, low-tech indicator of autonomic state. Warming typically indicates reduced sympathetic activation and increased blood flow, suggesting successful practice.

HRV Myths

Dr. Inna Khazan addresses common misconceptions about HRV and HRV biofeedback in this video. Understanding these myths helps clinicians provide accurate information to clients and avoid common pitfalls in training.

Assignment

Now that you have completed this unit, think about why you incorporate specific relaxation exercises in your practice. What do you expect each to accomplish? How do you encourage client practice? How do you assess compliance?

Glossary

References

Achterberg, J. (1994). Rituals of healing: Using imagery for health and wellness. Bantam.

Adlard, P. A., Perreau, V. M., Pop, V., & Cotman, C. W. (2005). Voluntary exercise decreases amyloid load in a transgenic model of Alzheimer's Disease. The Journal of Neuroscience, 25(17), 4217-4221. https://doi.org/10.1523/JNEUROSCI.0496-05.2005

Agostoni, C. V., Bresson, J. L., Fairweather Tait, S., Flynn, A., Golly, I., Korhonen, H., Lagiou, P., Livik, M., Marchelli, R., Martin, A., & Moseley, B. (2010). Scientific opinion on dietary reference values for water. EFSA Journal, 8(3), 1459.

Altini, M., & Plews, D. (2021). What is behind changes in resting heart rate and heart rate variability? Sensors, 21(23), 7932. https://doi.org/10.3390/s21237932

Barber, T. X. (1982). Hypnosuggestive procedures in the treatment of clinical pain: Implications for theories of hypnosis and suggestive therapy. In T. Millon, C. J. Green, & R. B. Meagher (Eds.), Handbook of clinical health psychology. Plenum.

Barber, J. (1996). A brief introduction to hypnotic analgesia. In J. Barber (Ed.), Hypnosis and suggestion in the treatment of pain: A clinical guide. Norton.

Bax, A., Robinson, T., Goedde, J., & Shaffer, F. (2007). The Cousins relaxation exercise increases heart rate variability [Abstract]. Applied Psychophysiology and Biofeedback, 32, 52-72. https://doi.org/10.1007/s10484-007-9032-z

Benson, H. (1975). The relaxation response. Morrow.

Berchtold, N. C., Chinn, G., Chou, M., Kesslak, J. P., & Cotman, C. W. (2005). Exercise primes a molecular memory for brain-derived neurotrophic factor protein induction in the rat hippocampus. Neuroscience, 133, 853-861. https://doi.org/10.1016/j.neuroscience.2005.03.026

Bernstein, D. A., & Borkovec, T. D. (1973). Progressive relaxation training: A manual for the helping professions. Research Press.

Blanchard, E. B., & Epstein, L. H. (1978). A biofeedback primer. Addison-Wesley.

Bornemann, B., Kok, B. E., Böckler, A., & Singer, T. (2019). Voluntary upregulation of heart rate variability through biofeedback is improved by mental contemplative training. Scientific Reports, 9, 7860. https://doi.org/10.1038/s41598-019-44201-7

Brannon, L., Feist, J., & Updegraff, J. A. (2018). Health psychology (9th ed.). Wadsworth Publishing Company.

Brannon, L., Feist, J., & Updegraff, J. A. (2022). Health psychology (10th ed.). Cengage Learning.

Breedlove, S. M., & Watson, N. V. (2020). Behavioral neuroscience (9th ed.). Sinauer Associates, Inc.

Breznoscakova, D., Kovanicova, M., Sedlakova, E., & Pallayova, M. (2023). Autogenic training in mental disorders: What can we expect? International Journal of Environmental Research and Public Health, 20(5), 4344. https://doi.org/10.3390/ijerph20054344

Bridges, L. J., Denham, S. A., & Ganiban, J. M. (2004). Definitional issues in emotion regulation research. Child Development, 75(2), 340-345. https://doi.org/10.1111/j.1467-8624.2004.00675.x

Brookshire, B. (2026, January 15). This little-known type of fat may actually protect your heart. National Geographic.

Brown, D. K., Barton, J. L., & Gladwell, V. F. (2013). Viewing nature scenes positively affects recovery of autonomic function following acute-mental stress. Environmental Science & Technology, 47(11), 5562-5569. https://doi.org/10.1021/es305019p

Buchheit, M., Laursen, P. B., Al Haddad, H., & Ahmaidi, S. (2009). Exercise-induced plasma volume expansion and post-exercise parasympathetic reactivation. European Journal of Applied Physiology, 105, 471-481. https://doi.org/10.1007/s00421-008-0925-1

Budzynski, T. (1994). The new frontier. Megabrain Report, 3, 58-65.

Carrington, P. (1999). Clinically standardized meditation (CSM) instructor's kit. Pace Educational Systems.

Carrington, P., & Lehrer, P. M. (2021). Modern forms of mantra meditation for stress management. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Carter, R., Cheuvront, S. N., Wray, D. W., Kolka, M. A., Stephenson, L. A., & Sawka, M. N. (2005). The influence of hydration status on heart rate variability after exercise heat stress. Journal of Thermal Biology, 30(7), 495-502. https://doi.org/10.1016/j.jtherbio.2005.05.006

Colino, S. (2026, January 23). You might be stretching the wrong way, scientists say. National Geographic.

Constant, I., Laude, D., Murat, I., & Elghozi, J.-L. (1999). Pulse rate variability is not a surrogate for heart rate variability. Clinical Science, 97(4), 391-397. https://doi.org/10.1042/cs0970391

de Oliveira, R. A. M., Araújo, L. F., de Figueiredo, R. C., Goulart, A. C., Schmidt, M. I., Barreto, S. M., & Ribeiro, A. L. P. (2017). Coffee consumption and heart rate variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) Cohort Study. Nutrients, 9(7), 741. https://doi.org/10.3390/nu9070741

Dmitrieva, N. I., Gagarin, A., Liu, D., Wu, C. O., & Boehm, M. (2023). Middle-age high normal serum sodium as a risk factor for accelerated biological aging, chronic diseases, and premature mortality. eBioMedicine, 104404.

Dmitrieva, N. I., Rosing, D. R., & Boehm, M. (2022). Making decision about fluid intake: increase or not increase. European Heart Journal, 43(41), 4438-4439. https://doi.org/10.1093/eurheartj/ehac368

Drew, B. J., Califf, R. M., Funk, M., Kaufman, E. S., Krucoff, M. W., Laks, M. M., Macfarlane, P. W., Sommargren, C., Swiryn, S., & Van Hare, G. F. (2004). Practice standards for electrocardiographic monitoring in hospital settings: An American Heart Association scientific statement. Circulation, 110(17), 2721-2746. https://doi.org/10.1161/01.CIR.0000145144.56673.59

Fox, S. I., & Rompolski, K. (2021). Human physiology (16th ed.). McGraw-Hill Education.

Freedman, R. R., Ianni, P., & Wenig, P. (1983). Behavioral treatment of Raynaud's disease. Journal of Consulting and Clinical Psychology, 51(4), 539-549. https://doi.org/10.1037/0022-006X.51.4.539

Fried, R. (1987). The hyperventilation syndrome: Research and clinical treatment. Johns Hopkins University Press.

Fried, R., & Grimaldi, J. (1993). The psychology and physiology of breathing. Springer.

Fung, T. T., Willett, W. C., Stampfer, M. J., Manson, J. E., & Hu, F. B. (2001). Dietary patterns and the risk of coronary heart disease in women. Archives of Internal Medicine, 161(15), 1857-1862. https://doi.org/10.1001/archinte.161.15.1857

Gard, T., Hölzel, B. K., & Lazar, S. W. (2014). The potential effects of meditation on age-related cognitive decline: A systematic review. Annals of the New York Academy of Sciences, 1307(1), 89-103. https://doi.org/10.1111/nyas.12348

Germer, C. K. (2005). Mindfulness: What is it? What does it matter? In C. K. Germer, R. D. Siegel, & P. R. Fulton (Eds.), Mindfulness and psychotherapy (pp. 3-27). Guilford Press.

Gevirtz, R. N. (2005). Heart rate variability biofeedback in clinical practice. AAPB Fall workshop.

Gevirtz, R. N. (2021). Personal communication regarding HRVB training goals.

Gevirtz, R. N., Lehrer, P. M., & Schwartz, M. S. (2016). Cardiorespiratory biofeedback. In M. S. Schwartz & F. Andrasik (Eds.). Biofeedback: A practitioner's guide (4th ed.). The Guilford Press.

Gilbert, C. (2012). Pulse oximetry and breathing training. Biofeedback, 40(4), 137-141. https://doi.org/10.5298/1081-5937-40.4.04

Gilbert, C. (2019). A guide to monitoring respiration. Biofeedback, 47(1), 6-11. https://doi.org/10.5298/1081-5937-47.1.02

Ginsberg, J. P., Berry, M. E., & Powell, D. A. (2010). Cardiac coherence and posttraumatic stress disorder in combat veterans. Alternative Therapies in Health and Medicine, 16(4), 52-60.

Goldfried, M. R. (1971). Systematic desensitization as training in self-control. Journal of Consulting and Clinical Psychology, 37(2), 228-234. https://doi.org/10.1037/h0031974

Gomez-Pinilla, F., Ying, Z., Opazo, P., Roy, R. R., & Edgerton, V. R. (2001). Differential regulation by exercise of BDNF and NT-3 in rat spinal cord and skeletal muscle. Eur J Neurosci, 13, 1078-84. https://doi.org/10.1046/j.0953-816x.2001.01484.x

Gonzales, J. U., Elavsky, S., Cipryan, L., Jandačková, V., Burda, M., & Jandačka, D. (2023). Influence of sleep duration and sex on age-related differences in heart rate variability: Findings from program 4 of the HAIE study. Sleep Medicine, 106, 69-77. https://doi.org/10.1016/j.sleep.2023.03.029

Grant, J., Wally, C., & Truitt, A. (2010). The effects of Kargyraa throat-singing and singing a fundamental note on heart rate variability [Abstract]. Poster presented at the meeting of the Biofeedback Foundation of Europe, Rome, Italy.

Grossman, P., & Kollai, M. (1993). Respiratory sinus arrhythmia, cardiac vagal tone, and respiration: Within- and between-individual relations. Psychophysiology, 30(5), 486-495. https://doi.org/10.1111/j.1469-8986.1993.tb02072.x

Guarino, D., Nannipieri, M., Iervasi, G., Taddei, S., & Bruno, R. M. (2017). The role of the autonomic nervous system in the pathophysiology of obesity. Frontiers in Physiology, 8, 665. https://doi.org/10.3389/fphys.2017.00665

Guidelines for practice. International Society for Neuroregulation & Research. Retrieved from https://isnr.org/guidelines-for-practice.

Gurung, R. A. R. (2018). Health psychology: Well-being in a diverse world (4th ed.). Thompson Wadsworth.

Hall, K. D., Ayuketah, A., Brychta, R., Cai, H., Cassimatis, T., Chen, K. Y., Chung, S. T., Costa, E., Courville, A., Darcey, V., Fletcher, L. A., Forde, C. G., Gharib, A. M., Guo, J., Howard, R., Joseph, P. V., McGehee, S., Ouwerkerk, R., Raisinger, K., Rozga, I., … Zhou, M. (2019). Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake. Cell Metabolism, 30(1), 67-77.e3. https://doi.org/10.1016/j.cmet.2019.05.008

Hammond, D. C., Stockdale, S., Hoffman, D., Ayers, M. E., & Nash, J. (2001). Adverse reactions and potential iatrogenic effects in neurofeedback training. Journal of Neurotherapy, 4(4), 57-69. https://doi.org/10.1300/J184v04n04_09

Hemon, M. C., & Phillips, J. P. (2016). Comparison of foot finding methods for deriving instantaneous pulse rates from photoplethysmographic signals. Journal of Clinical Monitoring and Computing, 30(2), 157-168. https://doi.org/10.1007/s10877-015-9695-6

Hilgard, E. R. (1978). Hypnosis and pain. In R. A. Sternbach (Ed.). The psychology of pain. Raven Press.

Hölzel, B. K., Carmody, J., Evans, K. C., Hoge, E. A., Dusek, J. A., Morgan, L., Pitman, R. K., & Lazar, S. W. (2009). Stress reduction correlates with structural changes in the amygdala. Social Cognitive and Affective Neuroscience, 5(1), 11-17. https://doi.org/10.1093/scan/nsp034

Institute of Medicine of the National Academies. (2005). Water. Dietary reference intakes for water, potassium, chloride, and sulfate. The National Academies Press.

Islam, M. R., Valaris, S., Young, M. F., Haley, E. B., Luo, R., Bond, S. F., Mazuera, S., Kitchen, R. R., Caldarone, B. J., Bettio, L. E. B., Christie, B. R., Schmider, A. B., Soberman, R. J., Besnard, A., Jedrychowski, M. P., Kim, H., Tu, H., Kim, E., Choi, S. H., Tanzi, R. E., Spiegelman, B. M., & Wrann, C. D. (2021). Exercise hormone irisin is a critical regulator of cognitive function. Nature Metabolism, 3, 1058-1070. https://doi.org/10.1038/s42255-021-00438-z

Jacobs, A. L., Kurtz, R. M., & Strube, M. J. (1995). Hypnotic analgesia, expectancy effects, and choice of a design: A reexamination. International Journal of Clinical and Experimental Hypnosis, 43, 45-68. https://doi.org/10.1080/00207149508409375

Jacobson, E. (1924). The technic of progressive relaxation. The Journal of Nervous and Mental Disease, 60(6), 568-578. https://doi.org/10.1097/00005053-192412000-00002

Jacobson, E. (1929). Progressive relaxation: A physiological and clinical investigation of muscular states and their significance in psychology and medical practice. University of Chicago Press.

Jacobson, E. (1934). You must relax: A practical method of reducing the strains of modern living. McGraw-Hill.

Jan, H.-Y., Chen, M.-F., Fu, T.-C., Lin, W.-C., Tsai, C.-L., & Lin, K.-P. (2019). Evaluation of coherence between ECG and PPG derived parameters on heart rate variability and respiration in healthy volunteers with/without controlled breathing. Journal of Medical and Biological Engineering, 39, 783-795. https://doi.org/10.1007/s40846-019-00468-9

Jones, H. G., Rizzo, R. R. N., Pulling, B. W., Braithwaite, F. A., Grant, A. R., McAuley, J. H., Jensen, M. P., Moseley, G. L., Rees, A., & Stanton, T. R. (2024). Adjunctive use of hypnosis for clinical pain: A systematic review and meta-analysis. Pain Reports, 9(5), e1185. https://doi.org/10.1097/PR9.0000000000001185

Kabat-Zinn, J. (1994). Wherever you go, there you are: Mindfulness meditation in everyday life. Hyperion.

Kabins, A., Goedde, J., Layne, B., & Grant, J. (2008). Brief coaching increases inhalation volume [Abstract]. Applied Psychophysiology and Biofeedback, 33(3), 174.

Kalil, G. Z., & Haynes, W. G. (2012). Sympathetic nervous system in obesity-related hypertension: Mechanisms and clinical implications. Hypertension Research, 35(1), 4-16. https://doi.org/10.1038/hr.2011.173

Karlin, R. A. (2021). The treatment of pain and stress with hypnosis: A series of emerging literatures. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Kekecs, Z., Bowers, J., Johnson, A., Kendrick, C., & Elkins, G. (2016). The Elkins Hypnotizability Scale: Assessment of reliability and validity. Int J Clin Exp Hypn, 64, 285-304. https://doi.org/10.1080/00207144.2016.1171089

Khazan, I. Z. (2013). The clinical handbook of biofeedback: A step-by-step guide for training and practice with mindfulness. John Wiley & Sons, Ltd.

Khazan, I. Z. (2019). Biofeedback and mindfulness in everyday life: Practical solutions for improving your health and performance. W. W. Norton & Company.

Khazan, I. (2021). Respiratory anatomy and physiology. BCIA HRV Biofeedback Certificate of Completion Didactic workshop.

Khazan, I. Z. (2026). Personal communication regarding resonance frequency and breathing rate.

Khedkar, S. (2025). Exerkines: Molecular messengers that mediate exercise effects. The Scientist. https://doi.org/10.1038/s41574-022-00641-2

Kim, H. J., Ryu, H., Kang, E., Kang, M., Han, M., Song, S. H., Lee, J., Jung, J. Y., Lee, K.-B., Sung, S., Seong, E. Y., Ahn, C., & Oh, K.-H. (2021). Metabolic acidosis is an independent risk factor of renal progression in Korean chronic kidney disease patients: The KNOW-CKD study results. Frontiers in Medicine, 8, 707588. https://doi.org/10.3389/fmed.2021.707588

Kirsch, I., & Lynn, S. (1995). The altered state of hypnosis: Changes in the theoretical landscape. American Psychologist, 50, 846-858. https://doi.org/10.1037/0003-066X.50.10.846

Kirsch, I., Montgomery, G., & Sapirstein, G. (1995). Hypnosis as an adjunct to cognitive-behavioral psychotherapy: A meta-analysis. Journal of Consulting and Clinical Psychology, 63(2), 214-220. https://doi.org/10.1037/0022-006X.63.2.214

Kitabchi, A. E., Umpierrez, G. E., Miles, J. M., & Fisher, J. N. (2009). Hyperglycemic crises in adult patients with diabetes. Diabetes Care, 32(7), 1335-1343. https://doi.org/10.2337/dc09-9032

Kohlert, A., Wick, K., & Rosendahl, J. (2022). Autogenic training for reducing chronic pain: A systematic review and meta-analysis of randomized controlled trials. International Journal of Behavioral Medicine, 29(5), 531-542. https://doi.org/10.1007/s12529-021-10038-6

Kok, B. E., & Singer, T. (2017). Phenomenological fingerprints of four meditations: Differential state changes in affect, mind-wandering, meta-cognition, and interoception. Mindfulness, 8, 218-231. https://doi.org/10.1007/s12671-016-0594-9

Kouhpayeh, M. S., Khezri, S., Goli, R., Faraji, N., Choobi Anzali, B., Maroofi, H., Hassanpour, A., & Nourazar, M. A. (2024). The effect of guided imagery on perioperative anxiety in hospitalized adult patients: A systematic review of randomized controlled trials. Surgery in Practice and Science, 18, 100255. https://doi.org/10.1016/j.sipas.2024.100255

Kral, T., Davis, K., Korponay, C., Hirshberg, M. J., Hoel, R., Tello, L. Y., Goldman, R. I., Rosenkranz, M. A., Lutz, A., & Davidson, R. J. (2022). Absence of structural brain changes from mindfulness-based stress reduction: Two combined randomized controlled trials. Science Advances, 8(20), eabk3316. https://doi.org/10.1126/sciadv.abk3316

Kristeller, J. L. (2021). Mindfulness meditation for stress management. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Lagos, L. (2020). Heart breath mind: Train your heart to conquer stress and achieve success. Houghton Mifflin Harcourt.

Lagos, L., Vaschillo, E., Vaschillo, B., Lehrer, P., Bates, M., & Pandina, R. (2011). Virtual reality assisted heart rate variability biofeedback as a strategy to improve golf performance: A case study. Biofeedback, 39(1), 15-20. https://doi.org/10.5298/1081-5937-39.1.11

Larson, E. B., Wang, L., Bowen, J. D., McCormick, W. C., Teri, L., Crane, P., & Kukull, W. (2006). Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older. Annals of Internal Medicine, 144(2), 73-81. https://doi.org/10.7326/0003-4819-144-2-200601170-00004

Lazar, S. W., Kerr, C. E., Wasserman, R. H., Gray, J. R., Greve, D. N., Treadway, M. T., McGarvey, M., Quinn, B. T., Dusek, J. A., Benson, H., Rauch, S. L., Moore, C. I., & Fischl, B. (2005). Meditation experience is associated with increased cortical thickness. Neuroreport, 16(17), 1893. PMID: 16272874

Lehrer, P. M. (2007). Biofeedback training to increase heart rate variability. In P. M. Lehrer, R. M. Woolfolk, & W. E. Sime (Eds.). Principles and practice of stress management (3rd ed.). The Guilford Press.

Lehrer, P. M. (2013). How does heart rate variability biofeedback work? Resonance, the baroreflex, and other mechanisms. Biofeedback, 41, 26-31. https://doi.org/10.5298/1081-5937-41.1.02

Lehrer, P., & Carrington, P. (2003). Progressive relaxation, autogenic training, and meditation. In D. Moss, A. McGrady, T. C. Davies, & I. Wickramasekera (Eds.), Handbook of mind-body medicine for primary care. Sage Publications.

Lehrer, P. M., & Gevirtz, R. (2014). Heart rate variability biofeedback: How and why does it work? Frontiers in Psychology, 5, 756. https://doi.org/10.3389/fpsyg.2014.00756

Lehrer, P., Kaur, K., Sharma, A., Shah, K., Huseby, R., Bhavsar, J., Sgobba, P., & Zhang, Y. (2020). Heart rate variability biofeedback improves emotional and physical health and performance: A systematic review and meta analysis. Applied Psychophysiology and Biofeedback, 45(3), 109-129. https://doi.org/10.1007/s10484-020-09466-z

Lehrer, P. M., Vaschillo, E., & Vaschillo, B. (2000). Resonant frequency biofeedback training to increase cardiac variability: Rationale and manual for training. Applied Psychophysiology and Biofeedback, 25(3), 177-191. https://doi.org/10.1023/a:1009554825745

Lehrer, P. M., Vaschillo, E., Vaschillo, B., Lu, S. E., Eckberg, D. L., Edelberg, R., . . . Hamer, R. M. (2003). Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow. Psychosomatic Medicine, 65(5), 796-805.

Lehrer, P., Vaschillo, B., Zucker, T., Graves, J., Katsamanis, M., Aviles, M., & Wamboldt, F. (2013). Protocol for heart rate variability biofeedback training. Biofeedback, 41(3), 98-109. https://doi.org/10.5298/1081-5937-41.3.08

Lehrer, P. M., Woolfolk, R. L., & Sime, W. E. (Eds.). (2021). Principles and practice of stress management (4th ed.). Guilford Press.

Li, W. W., Nannestad, J., Leow, T., & Heward, C. (2024). The effectiveness of mindfulness-based stress reduction (MBSR) on depression, PTSD, and mindfulness among military veterans: A systematic review and meta-analysis. Health Psychology Open, 11(2). https://doi.org/10.1177/20551029241302029

Lichstein, K. L. (1988). Clinical relaxation strategies. John Wiley & Sons.

Linden, W. (1990). Autogenic training: A clinical guide. The Guilford Press.

Linden, W. (1994). Autogenic training: A narrative and a meta-analytic review of outcome. Biofeedback and Self-Regulation, 19, 227-264. https://doi.org/10.1007/BF01721069

Linden, W. (2021). The autogenic training method of J. H. Schultz. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Ludwig, D. S., Pereira, M. A., Kroenke, C. H., Hilner, J. E., Van Horn, L., Slattery, M., . . . Jacobs, D. R. Jr. (1999). Dietary fiber, weight gain, and cardiovascular risk factors in young adults. Journal of the American Medical Association, 282(16), 1539-1546. https://doi.org/10.1001/jama.282.16.1539

Lutz, A., Jha, A. P., Dunne, J. D., & Saron, C. D. (2015). Investigating the phenomenological matrix of mindfulness-related practices from a neurocognitive perspective. American Psychologist, 70(7), 632-658. https://doi.org/10.1037/a0039585

Lynn, S. J., Laurence, J.-R., & Kirsch, I. (2015). Hypnosis, suggestion, and suggestibility: An integrative model. Am J Clin Hypn, 57, 314-29. https://doi.org/10.1080/00029157.2014.976783

McCraty, R. (2013). Personal communication regarding the benefits of heartfelt emotion.

McCraty, R., Atkinson, M., Tiller, W. A., Rein, G., & Watkins, A. D. (1995). The effects of emotions on short-term power spectrum analysis of heart rate variability. American Journal of Cardiology, 76(14), 1089-1093. https://doi.org/10.1016/s0002-9149(99)80309-9

McCraty, R., Atkinson, M., Tomasino, D., & Bradley, R. T. (2006). The coherent heart. Institute of HeartMath.

McDonald, J. W. (2004). Repairing the damaged spinal cord: From stem cells to activity-based restoration therapies. Clinical Neurosurgery, 51, 207-227.

McDonald, J. W., Becker, D., Sadowsky, C. L., Jane, J. A., Conturo, T. E., & Schultz, L. M. (2002). Late recovery following spinal cord injury. Journal of Neurosurgery, 97, 252-265. https://doi.org/10.3171/spi.2002.97.2.0252

McGuigan, F. M., & Lehrer, P. M. (2021). Progressive relaxation: Origins, principles, and clinical applications. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Medeiros, R. F., Silva, B. M., Neves, F. J., Rocha, N. G., Sales, A. R. K., & Nobrega, A. C. (2011). Impaired hemodynamic response to mental stress in subjects with prehypertension is improved after a single bout of maximal dynamic exercise. Clinics, 66(9), 1523-1529. https://doi.org/10.1590/S1807-59322011000900003

Mee-Inta, O., Zhao, Z.-W., & Kuo, Y.-M. (2019). Physical exercise inhibits inflammation and microglial activation. Cells, 8(7), 691. https://doi.org/10.3390/cells8070691

Mentoring for neurofeedback certification. Biofeedback Certification International Alliance. Retrieved from https://www.bcia.org/i4a/pages/index.cfm?pageid=3472.

Metzl, J. D. (2025, February 9). Want to lose weight? Here's why exercise probably won't help. The Washington Post. https://www.washingtonpost.com/wellness/2025/02/09/exercise-weight-loss/

Miller, M. F., Barabasz, A. F., & Barabasz, M. (1991). Effects of active alert and relaxation hypnotic inductions on cold pressor pain. Journal of Abnormal Psychology, 100, 223-226. https://doi.org/10.1037//0021-843x.100.2.223

Montgomery, G. H., Bovbjerg, D. H., Schnur, J. B., David, D., Goldfarb, A., Weltz, C. R., Schechter, C., Graff-Zivin, J., Tatrow, K., Price, D. D., & Silverstein, J. H. (2007). A randomized clinical trial of a brief hypnosis intervention to control side effects in breast surgery patients. J Natl Cancer Inst, 99(17), 1304-1312. https://doi.org/10.1093/jnci/djm106

Montgomery, G. H., David, D., Winkel, G., Silverstein, J. H., & Bovbjerg, D. H. (2002). The effectiveness of adjunctive hypnosis with surgical patients: A meta-analysis. Anesth Analg, 94(6), 1639-1645. https://doi.org/10.1097/00000539-200206000-00052

Montgomery, G. H., DuHamel, K. N., & Redd, W. H. (2000). A meta-analysis of hypnotically induced analgesia: How effective is hypnosis? International Journal of Clinical and Experimental Hypnosis, 48, 138-153. https://doi.org/10.1080/00207140008410045

Morgan, A. H. (1973). The heritability of hypnotic susceptibility in twins. J Abnorm Psychol, 82, 55-61. https://doi.org/10.1037/h0034854

Moss, D. (2004). Adjunctive interventions and assessment. In A. Crider & D. D. Montgomery (Eds.), Introduction to biofeedback. Association for Applied Psychophysiology and Biofeedback.

Moss, D. (2020). Biofeedback-assisted relaxation training: A clinically effective treatment protocol. Biofeedback, 48(2), 32-40. https://doi.org/10.5298/1081-5937-48.02.02

Moss, D. (2022). HRV biofeedback bootcamp. Association for Applied Psychophysiology and Biofeedback.

Moss, D., & Willmarth, E. (2019). Hypnosis, anesthesia, pain management, and preparation for medical procedures. Ann Palliat Med, 8(4), 498-503. https://doi.org/10.21037/apm.2019.07.01

Muhammad Khir, S., Wan Mohd Yunus, W. M. A., Mahmud, N., Wang, R., Panatik, S. A., Sukor, M. S. M., & Nordin, N. A. (2024). Efficacy of progressive muscle relaxation in adults for stress, anxiety, and depression: A systematic review. Psychology Research and Behavior Management, 17, 345-365. https://doi.org/10.2147/PRBM.S437277

Nakayama, N., Miyachi, M., Tamakoshi, K., Hayashi, T., Negi, K., Watanabe, K., & Hirai, M. (2021). Decreased continuous sitting time increases heart rate variability in patients with cardiovascular risk factors. PLoS ONE, 16(6), e0253399. https://doi.org/10.1371/journal.pone.0253399

Nash, M. R. (2001, July). The truth and the hype of hypnosis. Scientific American, 285, 46-55. https://doi.org/10.1038/scientificamerican0701-46

Nash, J., Stockdale, S., & Hoffman, D. A. (2001). Question: Have you seen any negative effects associated with EEG neurofeedback? Journal of Neurofeedback, 4, 65-69.

Neurofeedback essential skills list. Biofeedback Certification International Alliance (BCIA). Retrieved from https://www.bcia.org/files/public/EEG/NeurofeedbackEssentialSkillsList.pdf.

Ng, A. E., Black, L. I., & Adjaye-Gbewonyo, D. (2026). Short sleep duration and sleep difficulties among adults: United States, 2024 (NCHS Data Brief No. 559). National Center for Health Statistics. https://doi.org/10.15620/cdc/252438

Noetel, M., Sanders, T., Gallardo-Gómez, D., Taylor, P., Del Pozo Cruz, B., van den Hoek, D., Smith, J. J., Mahoney, J., Spathis, J., Moresi, M., Pagano, R., Pagano, L., Vasconcellos, R., Arnott, H., Varley, B., Parker, P., Biddle, S., & Lonsdale, C. (2024). Effect of exercise for depression: Systematic review and network meta-analysis of randomised controlled trials. BMJ, 384, e075847. https://doi.org/10.1136/bmj-2023-075847

O'Connor, A. (2022). What are ultra-processed foods? What should I eat instead? The Washington Post.

O'Connor, A. (2023). It's not just what you eat, but the time of day you eat it. The Washington Post.

Paluch, A. E., Gabriel, K. P., Fulton, J. E., Lewis, C. E., Schreiner, P. J., Sternfeld, B., Sidney, S., Siddique, J., Whitaker, K. M., & Carnethon, M. R. (2021). Steps per day and all-cause-mortality in middle-aged adults in the Coronary Artery Risk Development in Young Adults Study. JAMA Network Open, 4(9), e2124516. https://doi.org/10.1001/jamanetworkopen.2021.24516

Pan, Y., Li, F., Liang, H., Chen, L., Wang, J., Wei, W., Li, F., & Fu, D. (2024). Effectiveness of mindfulness-based stress reduction on mental health and psychological quality of life among university students: A GRADE-assessed systematic review. Evidence-Based Complementary and Alternative Medicine, 2024, 8872685. https://doi.org/10.1155/2024/8872685

Pardini, S., Gabrielli, S., Olivetto, S., Fusina, F., Dianti, M., Forti, S., & Lancini, S. (2024). Exploring virtual reality versus traditional guided imagery for reducing anxiety: A pilot randomized controlled trial. Cyberpsychology, Behavior, and Social Networking, 27(8), 596-605. https://doi.org/10.1089/cyber.2023.0594

Patterson, D. R. (2010). Clinical hypnosis for pain control. American Psychological Association.

Pelletier, K. R. (1977). Mind as healer, Mind as slayer. Dell Publishing Company, Incorporated.

Peper, E., & Gibney, K. H. (2005). Muscle biofeedback at the computer: A manual to prevent repetitive strain injury (RSI) by taking the guesswork out of assessment, monitoring, and training. Biofeedback Foundation of Europe.

Peper, E., Gibney, K. H., & Holt, C. F. (2002). Make health happen: Training yourself to create wellness (2nd ed.). Kendall Hunt Publishing Company.

Peper, E., Gibney, K. H., Tylova, H., Harvey, R., & Combatalade, D. (2008). Biofeedback mastery: An experiential teaching and self-training manual. Association for Applied Psychophysiology and Biofeedback.

Peper, E., Shumay, D. M., & Moss, D. (2012). Change illness beliefs with biofeedback and somatic feedback. Biofeedback, 40(4), 154-159. https://doi.org/10.5298/1081-5937-40.4.02

Peper, E., & Tibbets, V. (1994). Effortless diaphragmatic breathing. Physical Therapy Products, 6(2), 67-71.

Piccione, C., Hilgard, E. R., & Zimbardo, P. G. (1989). On the degree of stability of measured hypnotizability over a 25-year period. J Pers Soc Psychol, 56, 289-295. https://doi.org/10.1037//0022-3514.56.2.289

Pikoff, H. (1984). A critical review of autogenic training in America. Clinical Psychology Review, 4(6), 619-639. https://doi.org/10.1016/0272-7358(84)90009-6

Pinto, A. J., Bergouignan, A., Dempsey, P. C., Roschel, H., Owen, N., Gualano, B., & Dunstan, D. W. (2023). Physiology of sedentary behavior. Physiological Reviews, 103(4), 2561-2622. https://doi.org/10.1152/physrev.00022.2022

Porges, S. W. (2007). The polyvagal perspective. Biological Psychology, 74(2), 116-143. https://doi.org/10.1016/j.biopsycho.2006.06.009

Rosendahl, J., Alldredge, C. T., & Haddenhorst, A. (2024). Meta-analytic evidence on the efficacy of hypnosis for mental and somatic health issues: A 20-year perspective. Frontiers in Psychology, 14, 1330238. https://doi.org/10.3389/fpsyg.2023.1330238

Sadowsky, C. L., Hammond, E. R., Strohl, A. B., Commean, P. K., Eby, S. A., Damiano, D. L., Wingert, J. R., Bae, K. T., & McDonald, J. W. (2013). Lower extremity functional electrical stimulation cycling promotes physical and functional recovery in chronic spinal cord injury. The Journal of Spinal Cord Medicine, 36(6), 623-631. https://doi.org/10.1179/2045772313Y.0000000101

Saraiva, B. T. C., Tebar, W. R., Furuta, D. T., Silva, S. C. B., Antunes, E. P., Sousa, G., Ferrari, G., Vanderlei, L. C. M., & Christofaro, D. G. D. (2026). Association of meeting the 24-hour movement guidelines with heart rate variability in adults. European Journal of Applied Physiology. https://doi.org/10.1007/s00421-025-06115-3

Schultz, J. H., & Luthe, W. (1969). Autogenic therapy: Vol. 1. Autogenic methods. Grune & Stratton.

Schwartz, M. S. (2016). Intake decisions and preparation of patients for therapy. In M. S. Schwartz & F. Andrasik (Eds.). Biofeedback: A practitioner's guide (4th ed.). The Guilford Press.

Schwartz, M. S., & Andrasik, F. (Eds.). (2003). Biofeedback: A practitioner's guide (3rd ed.). Guilford Press.

Schwartz, M. S., Schwartz, N. M., & Monastra, V. J. (2016). Problems associated with relaxation procedures and biofeedback, and guidelines for management. In M. S. Schwartz & F. Andrasik (Eds.). Biofeedback: A practitioner's guide (4th ed.). The Guilford Press.

Seid, A. A., Mohammed, A. A., & Hasen, A. A. (2023). Progressive muscle relaxation exercises in patients with COVID-19: Systematic review and meta-analysis. Medicine, 102(14), e33464. https://doi.org/10.1097/MD.0000000000033464

Shaffer, F., Bergman, S., & Dougherty, J. (1998). End-tidal CO₂ is the best indicator of breathing effort [Abstract]. Applied Psychophysiology and Biofeedback, 23(2).

Shaffer, F., Bergman, S., & White, K. (1997). Indicators of diaphragmatic breathing effort [Abstract]. Applied Psychophysiology and Biofeedback, 22(2), 145.

Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258. https://doi.org/10.3389/fpubh.2017.00258

Shaffer, F., Greve, E., & Reinagel, K. (1996). Predictors of inhalation volume [Abstract]. Biofeedback and Self-Regulation, 21(4), 352.

Shaffer, F., Mayhew, J., Bergman, S., Dougherty, J., & Irwin, D. (1999). Designer jeans increase breathing effort [Abstract]. Applied Psychophysiology and Biofeedback, 24(2), 124-125.

Shaffer, F., McCraty, R., & Zerr, C. L. (2014). A healthy heart is not a metronome: An integrative review of the heart's anatomy and heart rate variability. Frontiers in Psychology. https://doi.org/10.3389/fpsyg.2014.01040

Shaffer, F., Meehan, Z. M., & Zerr, C. L. (2020). A practical guide to resonance frequency assessment for heart rate variability biofeedback. Frontiers in Neuroscience, 14, 570400. https://doi.org/10.3389/fnins.2020.570400

Shaffer, F., & Moss, D. (2006). Biofeedback. In Y. Chun-Su, E. J. Bieber, & B. Bauer (Eds.), Textbook of complementary and alternative medicine (2nd ed.). Informa Healthcare.

Shellenberger, R., & Green, J. A. (1986). From the ghost in the box to successful biofeedback training. Health Psychology Publications.

Singh, B., Olds, T., Curtis, R., Dumuid, D., Virgara, R., Watson, A., Szeto, K., O'Connor, E., Ferguson, T., Eglitis, E., Miatke, A., Simpson, C. E., & Maher, C. (2023). Effectiveness of physical activity interventions for improving depression, anxiety and distress: An overview of systematic reviews. British Journal of Sports Medicine, 57(18), 1203-1209. https://doi.org/10.1136/bjsports-2022-106195

Smith, J. C. (1985). Relaxation dynamics: Nine world approaches to self-relaxation. Research Press.

Smith, J. C. (1986). Meditation, biofeedback, and the relaxation controversy: A cognitive-behavioral perspective. American Psychologist, 41, 1007-1009.

Smith, J. C. (1990). Cognitive-behavioral relaxation training: A new system of strategies for treatment and assessment. Springer.

Smith, J. C. (1999). ABC relaxation theory. Springer.

Smith, J. C. (2001). Advances in ABC relaxation: Applications and inventories. Springer.

Smith, J. C. (2005). Relaxation, meditation, and mindfulness: A mental health professional's guide to new and traditional approaches. Springer.

Smith, J. C. (2007). The psychology of relaxation. In P. M. Lehrer, R. L. Woolfolk, & W. E. Sime (Eds.). Principles and practice of stress management (3rd ed.). The Guilford Press.

Smith, J. C. (2016). Relaxation today: Self-stressing and psychological relaxation theory. In M. S. Schwartz & F. Andrasik (Eds.). Biofeedback: A practitioner's guide (4th ed.). The Guilford Press.

Smith, J. C. (2017). Stress and coping: The eye of mindfulness. Kendall Hunt.

Smith, J. C. (2019). Third-generation mindfulness and the universe of relaxation. Kendall Hunt.

Smith, J. C. (2021). The psychology of relaxation. In P. M. Lehrer & R. L. Woolfolk (Eds.), Principles and practice of stress management (4th ed.). The Guilford Press.

Smith, J. C., Amutio, A., Anderson, J. P., & Aria, L. A. (1996). Relaxation: Mapping an uncharted world. Biofeedback and Self-Regulation, 21, 63-90. https://doi.org/10.1007/BF02214150

Smith, J. C., & Jackson, L. (2001). Breathing exercises and relaxation states. In J. C. Smith (Ed.), Advances in ABC relaxation: Applications and inventories (pp. 202-204). Springer.

Smith, J. C., & Joyce, C. A. (2004). Mozart vs. new age music: Relaxation states, stress, and ABC relaxation theory. Journal of Music Therapy, 41, 215-224. https://doi.org/10.1093/jmt/41.3.215

Smith, J. C., Wedell, A. B., Kolotylo, C. J., Lewis, J. E., Byers, K. Y., & Segin, C. M. (2000). ABC relaxation theory and the factor structure of relaxation states, recalled relaxation activities, dispositions, and motivations. Psychological Reports, 86, 1201-1208. https://doi.org/10.2466/pr0.2000.86.3c.1201

Stetter, F., & Kupper, S. (2002). Autogenic training: A meta-analysis of clinical outcome studies. Applied Psychophysiology and Biofeedback, 27, 45-98. https://doi.org/10.1023/a:1014576505223

Striefel, S. (2004). Module 8: Professional conduct. In A. Crider and D. D. Montgomery (Eds.). Introduction to biofeedback: An AAPB independent study program. Association for Applied Psychophysiology and Biofeedback.

Stroebel, C. F. (1982). QR: The quieting reflex. G. P. Putnam's Sons.

Surwit, R. S., Pilon, R. N., & Fenton, C. H. (1978). Behavioral treatment of Raynaud's disease. Journal of Behavioral Medicine, 1(3), 323-335. https://doi.org/10.1007/BF00846683

Suter, S. (1986). Health psychophysiology: Mind-body interactions in wellness and illness. Lawrence Erlbaum Associates.

Swingle, P. G. (2008). Biofeedback for the brain: How neurotherapy effectively treats depression, ADHD, autism, and more. Rutgers University Press.

Taub, E., & School, P. J. (1978). Some methodological considerations in thermal biofeedback training. Behavior Research Methods & Instrumentation, 10(5), 617-622. https://doi.org/10.3758/BF03205359

Taylor, S. E. (2018). Health psychology (10th ed.). McGraw-Hill Education.

Taylor, S. E., & Stanton, A. L. (2021). Health psychology (11th ed.). McGraw Hill.

Thayer, J. F., & Sternberg, E. (2006). Beyond heart rate variability: Vagal regulation of allostatic systems. Annals of the New York Academy of Sciences, 1088(1), 361-372. https://doi.org/10.1196/annals.1366.014

Thompson, M., & Thompson, L. (2015). Neurofeedback book: An introduction to basic concepts in applied psychophysiology (2nd ed.). Association for Applied Psychophysiology and Biofeedback.

Tsunetsugu, Y., Park, B. J., & Miyazaki, Y. (2010). Trends in research related to "Shinrin-yoku" (taking in the forest atmosphere or forest bathing) in Japan. Environmental Health and Preventive Medicine, 15(1), 27-37. https://doi.org/10.1007/s12199-009-0091-z

Turkelson, L., & Mano, Q. (2021). The current state of mind: A systematic review of the relationship between mindfulness and mind-wandering. Journal of Cognitive Enhancement. https://doi.org/10.1007/s41465-021-00231-6

U.S. Department of Health and Human Services (USDHHS). (2018). Physical activity guidelines for Americans (2nd ed.). Author.

Vaddadi, G. (2016). Cardiovascular risk factors: Role of lifestyle. In M. E. Alvarenga, & D. Byrne (Eds.). Handbook of psychocardiology. Springer Singapore.

Van Praag, H., Christie, B. R., Sejnowski, T. J., & Gage, F. H. (1999). Running enhances neurogenesis, learning, and long-term potentiation in mice. Proc Natl Acad Sci USA, 96, 13427-13431. https://doi.org/10.1073/pnas.96.23.13427

Vansickle, J., Putnam, R., Harris, M., Garcia, M., Bell, B., Nelson, M., & Lowery, L. (2020). Caffeine intake does not negatively affect heart rate variability in physically active university students: Preliminary findings. Current Development in Nutrition, 4(Supplement 2), 1770. https://doi.org/10.1093/cdn/nzaa066_025

Vaschillo, E., Lehrer, P., Rishe, N., & Konstantinov, M. (2002). Heart rate variability biofeedback as a method for assessing baroreflex function: A preliminary study of resonance in the cardiovascular system. Applied Psychophysiology and Biofeedback, 27, 1-27. https://doi.org/10.1023/a:1014587304314

Vaschillo, E. G., Vaschillo, B., & Lehrer, P. M. (2006). Characteristics of resonance in heart rate variability stimulated by biofeedback. Applied Psychophysiology and Biofeedback, 31(2), 129-142. https://doi.org/10.1007/s10484-006-9009-3

Vaschillo, E. G., Vaschillo, B., Pandina, R. J., & Bates, M. E. (2011). Resonances in the cardiovascular system caused by rhythmical muscle tension. Psychophysiology, 48, 927-936. https://doi.org/10.1111/j.1469-8986.2010.01156.x

Vujovic, N., Piron, M. J., Qian, J., Chellappa, S. L., Nedeltcheva, A., Barr, D., Heng, S. W., Kerlin, K., Srivastav, S., Wang, W., & Scheer, F. A. (2022). Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity. Cell Metabolism, 34(10), 1486-1498.

Wally, C., Korenfeld, I., Brooks, K., Carrell, D., Lau, D., Peterson, J., Schafer, M., Truitt, A., Fuller, J., Westermann-Long, A., & Korenfeld, D. (2011). Chanting "Om" increases heart rate variability by slowing respiration [Abstract]. Applied Psychophysiology and Biofeedback, 36, 223.

Watso, J. C., & Farquhar, W. B. (2019). Hydration status and cardiovascular function. Nutrients, 11(8), 1866. https://doi.org/10.3390/nu11081866

Wickramasekera, I. (2003). The high risk model of threat perception and the Trojan Horse role induction: Somatization and psychophysiological disease. In D. Moss, A. McGrady, T. C. Davies, & I. Wickramasekera (Eds.), Handbook of mind-body medicine for primary care. Sage Publications.

Wolpe, J. (1958). Psychotherapy by reciprocal inhibition. Stanford University Press.

Ylitalo, A., Airaksinen, K. E. J., Sellin, L., & Huikuri, H. V. (1999). Effects of combination antihypertensive therapy on baroreflex sensitivity and heart rate variability in systemic hypertension. American Journal of Cardiology, 83(6), 885-889. https://doi.org/10.1016/s0002-9149(98)01067-4

Young, I. E., Poobalan, A., Steinbeck, K., O'Connor, H. T., & Parker, H. M. (2022). Distribution of energy intake across the day and weight loss: A systematic review and meta-analysis. Obesity Reviews, e13537.

Zerr, C., Kane, A., Vodopest, T., Allen, J., Fluty, E., Gregory, J., DeBold, M., Schultz, D., Robinson, G., Golan, R., Hannan, J., Bowers, S., Cangelosi, A., Korenfeld, D., Jones, D., Shepherd, S., Burklund, Z., Spaulding, K., Hoffman, W., & Shaffer, F. (2014). HRV biofeedback training raises temperature and lowers skin conductance. Applied Psychophysiology and Biofeedback, 39(3), 299. https://doi.org/10.1007/s10484-014-92549

Zerr, C., Kane, A., Vodopest, T., Allen, J., Hannan, J., Fabbri, M., . . . Shaffer, F. (2015). Does inhalation-to-exhalation ratio matter in heart rate variability biofeedback? [Abstract]. Applied Psychophysiology and Biofeedback, 40(2), 135. https://doi.org/10.1007/s10484-015-9282-0

Zigmond, M. J., & Cotman, C. W. (2005). Exercise and central nervous system disease. Annual Meeting of the Society for Neuroscience.