Breathing assessment should always precede HRV biofeedback because dysfunctional breathing can frustrate training success.
Respiration assessment can provide a roadmap for correcting breathing mechanics before initiating HRV biofeedback.
Whether a clinician trains clients at their resonance frequency (RF) or 6 breaths per minute (bpm), measuring their typical breathing rate is crucial. Their resting respiration rate can warn the clinician of the need for extensive healthy breathing training before initiating RF assessment and HRV biofeedback.
Overbreathing may be the most common breathing problem. Its expulsion of CO2 can produce a spectrum of medical and psychological symptoms (Khazan, 2020).
This unit addresses V. HRV Biofeedback Strategies: B. How to assess breathing.
Professionals completing this unit will be able to discuss:
A. How to identify dysfunctional breathing behaviors
B. How to assess patient breathing using a respirometer, oximeter, and capnometer
This unit covers Waiting Room Assessment, Clinic Assessment, Assessment Protocol, and The Nijmegen Questionnaire.
Please click on the podcast icon below to hear a full-length lecture.
Both restrictive clothing and poor ergonomics can increase respiration rate beyond a client's resonance frequency,
lowering HRV.
3. Check for reverse breathing, in which the abdomen contracts during inhalation.
This breathing pattern can result in respiration rates that exceed the resonance frequency. In the screen capture
below, the pink tracing shows instantaneous heart rate (HR), and the violet tracing shows respirometer expansion and
contraction.
Caption: At the bottom left, the respirometer shows contraction instead of expansion during inspiration. The instantaneous heart rate and respirometer waveforms are also disorganized and choppy instead of sinusoidal like ocean waves.
4. Check for clavicular breathing, where the shoulders rise and fall during breathing.
Clavicular breathing often involves rapid breathing to compensate for shallow inhalation volumes. In the
screen capture below, the pink tracing shows accessory muscle (e.g., trapezius and scalene) SEMG, and the violet tracing shows respirometer
expansion and contraction.
Caption: The mean respiration rate is 19.95 bpm, almost three times the client's likely resonance frequency. See the elevated SEMG reading and reduced inspirometer expansion at the far right.
5. Check whether breathing is primarily thoracic or abdominal, using covert observation and a respirometer.
Thoracic breathing can speed respiration above your client's resonance frequency. In the screen capture below,
the pink tracing shows instantaneous HR, and the violet tracing shows respirometer expansion and contraction.
Caption: The mean respiration rate is 14.32, well above the client's likely resonance frequency, and the two waveforms are shallow and disorganized.
Compare this screen capture with the one below, which illustrates abdominal breathing. The mean respiration rate is
5.07. Both waveforms are sinusoidal with high amplitude and in-phase (their peaks and valleys
coincide).
6. Check for apnea, which is the suspension of breathing.
Apnea disrupts abdominal breathing and can raise blood pressure. In the screen capture below, the pink tracing shows
instantaneous HR, and the violet tracing shows respirometer expansion and contraction.
Caption: Toward the middle of the recording, the bottom of the inspirometer wave is flattened, denoting breath-holding.
7. Check respiration rate and amplitude (amount of respirometer movement). Thoracic breathing
at rates at or above 16 bpm may be associated with overbreathing or hyperventilation syndrome (HVS). Neblett (2013)
cautions that chronic pain patients may breathe faster than 20 bpm. The BioGraph ® Infiniti display below shows the shallow, rapid breathing that can characterize overbreathing.
8. Check breathing effort by monitoring the abdominal tracing for loss of a smooth sinusoidal pattern.
Caption: There are three inflection points in the screen capture below (marked by yellow arrows) where the second breathing cycle is distorted by effort.
9. Monitor accessory and frontal SEMG as a second index of breathing effort.
In the screen capture below, accessory SEMG is shown in pink and respirometer movement is shown in pink.
Caption: See the two SEMG spikes over 5 microvolts (around 00:14:47 and 00:14:58) that coincide with the last two inhalations.
11. Check end-tidal CO2 using a capnometer. A value of 36 torr (5%) is normal, while values
below 33 torr are seen in hyperventilation syndrome (HVS) and overbreathing. A healthy range is 35-45 torr. Values
below 25 mmHg signal severe overbreathing, 25-30 mmHg, moderate-to-severe overbreathing, and 30-35 mmHg,
mild-to-moderate overbreathing (Khazan, 2020).
Breathing Assessment Protocol
Breathing assessment requires an ECG or PPG sensor to monitor HRV, a respirometer to measure abdominal excursion and
respiration rate, and a SEMG sensor to evaluate accessory muscle activity. A capnometer to measure end-tidal CO2 and an oximeter to measure PO2 are optional.
Click on the Read More button to review a breathing evaluation protocol.
1. Check for reverse breathing: "Take a normal breath, hold it, and then exhale." Wait 30
seconds. "Take another normal breath and then exhale" (1 minute, no feedback). Watch the screen for evidence
of reverse breathing and accessory muscle overuse.
In the screen capture below,
the pink tracing shows instantaneous HR, and the violet tracing shows respirometer contraction and expansion.
Caption: There is evidence of reverse breathing since the respirometer tracing falls during inspiration and rises during expiration.
2. Resting baseline: "Breathe normally for the next 3 minutes" (3 minutes, with no feedback).
Watch the display for abdominal excursion, smooth respiration, breathing effort, respiration rate, synchrony between
the respiration and HR tracings, and apnea. Watch your client for gasping, shoulder movement, sighing, and yawning.
Caption: By the 00:2:30 mark, abdominal excursion becomes shallow, and respiration and HR move out of phase.
3. Serial-sevens stressor: "Mentally count backward from 1000 by 7s until I stop you and ask for
the number you are on" (3 minutes, no feedback). Watch the display for abdominal excursion, smooth respiration,
breathing effort, respiration rate, synchrony between the respiration and HR tracings, and apnea. Watch your client for gasping, shoulder movement, sighing, and yawning.
Caption: HR starts to rise with the onset of the serial-sevens stressor around 00:4:05 and exceeds 13 bpm at several points during this trial. The mean respiration rate is around 13 bpm compared with 11 bpm during the resting baseline. Around the 00:4:45 mark, effort is indicated by the large respirometer excursion and an 8-microvolt spike in accessory SEMG activity.
4. Recovery 1: "Stop subtracting and breathe normally for the next 3 minutes" (3 minutes, no
feedback). Watch the display for abdominal excursion, smooth respiration, breathing effort, respiration rate, synchrony
between the respiration and HR tracings, and apnea. Watch your client for gasping, shoulder movement, sighing, and yawning.
Caption: HR starts to slow soon after the recovery instructions around mark 00:07:15. By mark 00:07:30, both respirometer and HR tracings become sinusoidal and synchronous. Accessory muscle activity is unremarkable, except for a single spike around mark 00:08:26.
5. Visualize a mildly upsetting experience: "Use all of your senses to recreate a mildly upsetting experience vividly. Raise a finger when you are re-experiencing the event and continue for the next 3 minutes (3
minutes, no feedback). Watch the display for abdominal excursion, smooth respiration, breathing effort, respiration
rate, synchrony between the respiration and HR tracings, and apnea. Watch your client for gasping, shoulder movement, sighing, and yawning.
Caption: HR starts to rise with the onset of the visualization stressor around mark 00:10:00, respiration amplitude decreases, and respirometer and HR synchrony disappears. There is a single incidence of breath-holding when the subject visualizes the event.
6. Recovery 2: "Stop your visualization and breathe normally for the next 3 minutes" (3
minutes, no feedback). Watch the display for abdominal excursion, smooth respiration, breathing effort, respiration
rate, synchrony between the respiration and HR tracings, and apnea. Watch your client for gasping, shoulder movement, sighing, and yawning.
Caption: Respiration amplitude and RSA increase, and synchrony returns about 30 seconds into the recovery trial. Accessory muscle activity also slightly decreases.
7. Hyperventilation challenge: "Breathe rapidly for the minute or until you are uncomfortable"
(1 minute, no feedback). Watch your client for signs of distress. Stop immediately if your client experiences dizziness,
pain, or panic. Watch for respiration rate, end-tidal CO2, and oxygen saturation. Common symptoms
of hyperventilation include feelings of anxiety, breathlessness, dizziness, lightheadedness, rapid heartbeat, and
tingling (Lehrer et al., 2013).
8. Recovery 3: "Stop breathing rapidly and breathe normally for the next 3 minutes" (3
minutes, no feedback). Watch for respiration rate, end-tidal CO2, and oxygen saturation.
Don Moss (2013) generously provided respiration rate and end-tidal CO2 data from a 53-year-old married
woman diagnosed with agoraphobia and panic disorder. The hyperventilation challenge was crucial to this patient's assessment and was conducted by an experienced licensed clinical psychologist.
Despite breathing at 18 bpm during baseline, her end-tidal CO2 was normal. The hyperventilation
challenge increased her respiration rate to 42 bpm and resulted in hypocapnia with an end-tidal CO2
of 26. During the recovery trial, her respiration rate decreased below baseline, but her end-tidal CO2 remained below the normal cutoff of 35 torr.
Summary of the Breathing Assessment Protocol
A mild hyperventilation challenge is contraindicated for clients diagnosed with epilepsy, heart disease, kidney disease,
panic disorder, and PTSD.
Clinicians may add the Stroop test followed by a recovery period.
Inna Khazan
(2019) provided an example of a breathing assessment using the Stroop test. The client was a 30-year-old woman who was divorcing her alcoholic husband. She presented with anxiety and diverse symptoms (difficulty focusing, GI distress, headaches, lightheadedness, racing heart, and shortness of breath).
Caption: Note that end-tidal CO2 remained below the normal (35-45 mmHg) range throughout the assessment. Although the client recovered from the math stressor, end-tidal CO2 further declined following the emotional stressor.
Nijmegen Questionnaire
There are approximately 100,000 miles of blood vessels in the brain, with a flow rate of about 750 milliliters per minute in adults.
The graphic below shows reduced cerebral blood perfusion (depicted by dark colors) during overbreathing, producing the Nijmegen questionnaire's symptoms.
A score of 23 out of 64 on the Nijmegen questionnaire suggests further screening for hyperventilation
syndrome.
Drug Effects
Glossary
accessory muscles: the sternocleidomastoid, pectoralis minor, scalene, and
trapezius muscles, which are used during forceful breathing, as well as during clavicular and thoracic breathing.
apnea: breath suspension.
behavioral breathlessness syndrome: the perspective that hyperventilation is the
consequence and not the cause of the disorder. The traditional model that hyperventilation results in reduced arterial
CO2 levels has been challenged by the finding that many HVS patients have normal arterial CO2 levels during attacks.
capnometer: an instrument that monitors the carbon dioxide (CO2) concentration in an air sample (end-tidal CO2) by measuring the absorption of infrared light.
clavicular breathing: a breathing pattern that primarily relies on the external
intercostals and the accessory muscles to inflate the lungs, resulting in a more rapid respiration rate, excessive
energy consumption, and incomplete ventilation of the lungs.
diaphragm: the dome-shaped muscle whose contraction enlarges the vertical diameter of
the chest cavity and accounts for about 75% of air movement into the lungs during relaxed breathing.
end-tidal CO2: the percentage of CO2 in exhaled air at the
end of exhalation.
hyperventilation syndrome (HVS): a respiratory disorder that has been increasingly reconceptualized as a
behavioral breathlessness syndromein which
hyperventilation is the consequence and not the cause of the disorder. The traditional model that hyperventilation
results in reduced arterial CO2 levels has been challenged by the finding that many HVS patients
have normal arterial CO2 levels during attacks.
overbreathing: a mismatch between breathing rate and depth due to excessive breathing effort and subtle breathing behaviors like sighs and yawns can reduce arterial CO2.
pulse oximeter: a device that measures dissolved oxygen in the bloodstream using a photoplethysmograph
sensor placed against a finger or earlobe.
respiratory amplitude: the excursion of an abdominal strain gauge.
resonance frequency: the breathing rate
that maximizes the most time-domain measurements of HRV.
respiratory sinus arrhythmia (RSA): HR acceleration during inspiration and deceleration during
expiration.
respirometer: a sensor that changes resistance to a
current as it expands and contracts during the respiratory cycle.
reverse breathing: the abdomen expands during exhalation and contracts during
inhalation, often resulting in incomplete ventilation of the lungs.
thoracic breathing: a breathing pattern that primarily relies on the external
intercostals to inflate the lungs, resulting in a more rapid respiration rate, excessive energy consumption, and
incomplete ventilation of the lungs.
torr: a unit of atmospheric pressure, named after Torricelli, which equals 1 millimeter of mercury (mmHg)
and is used to measure end-tidal CO2.
trapezius-scalene placement: the active SEMG electrodes are located on the upper trapezius and scalene
muscles to measure respiratory effort.
Test Yourself
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Visit the BioSource Software Website
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BCIA has accredited each course, and they combine affordable pricing ($150) with industry-leading content.
Assignment
Now that you have completed this module, how might you redesign your breathing assessment protocol? Which measurements
might you add?
References
Fried, R. (1987). The hyperventilation syndrome: Research and clinical
treatment. John Hopkins University Press.
Gevirtz, R. N. (2005). Heart rate variability biofeedback in clinical
practice. AAPB Fall workshop.
Khazan, I., & Shaffer, F. (2019). Practical strategies for teaching your clients to breathe. Association for Applied Psychophysiology and Biofeedback 50th Annual Meeting, Denver, CO.
Khazan, I. (2020).
The myths and misconceptions of heart rate variability. Association for Applied Psychophysiology and Biofeedback Virtual Conference.
Khazan, I. Z. (2013). The clinical handbook of biofeedback: A step-by-step guide for training and practice with
mindfulness. John Wiley & Sons, Ltd.
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
Neblett, R. (2013). Personal communication about breathing patterns in chronic pain patients.
Peper, E., Gibney, K. H., Tylova, H., Harvey, R., & Combatalade, D. (2008). Biofeedback mastery: An experiential
teaching and self-training manual. Wheat Ridge, CO: AAPB.
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., & Henson, M. (1998). Description of the Truman
breathing assessment protocol [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., & Moss, D. (2006). Biofeedback. In Y. Chun-Su, E. J.
Bieber, & B. Bauer (Eds.). Textbook of complementary and alternative
medicine (2nd ed.). Abingdon, Oxfordshire, UK: Informa Healthcare.
