• Johanna Bergstrom

A Biofeedback Hack: Controlling Stress Through Resonant Breathing

Previously, we’ve explored the basics of heart rate variability (HRV) and how it can serve as a useful tool for monitoring physical and mental health.


That is all well and good, but what can we actually do about it? Are there concrete, practical ways to use the science of HRV to significantly improve our health?


Fortunately, current research answers that question with a resounding yes.



Altering your brain’s response to stress is much less complicated than you might expect. In fact, reducing stress often starts by modifying your body’s simplest tasks. Building a healthier, less-anxious self begins from the ground up.


Respiration and Stress


Let’s talk about one of the most basic functions your body performs: breathing. The average adult has a respiration rate of 12–20 breaths per minute.¹­


Respiration rate is partially controlled by the vagus nerve, a key pathway linking the brain to organs throughout the body.²


The vagus nerve in particular is intimately involved in our experience of stress. It transmits information between emotional centers in the brain and major organs like the heart and lungs.³ When our brain detects a threat, signals travel back and forth along these pathways, creating a well-coordinated response.⁴


The polyvagal theory suggests that the vagus nerve actually includes several distinct pathways.⁵ One such pathway, the vegetative vagus, generates the instinctive “fight, flight, or freeze” response.⁶


The other “smart vagus” pathway controls our voluntary response — our ability to consciously calm ourselves down.⁷ It also helps coordinate heart rate and respiration rate so that they occur as “in sync” with one another as possible.⁸


In other words, HRV, respiration, and stress are closely interconnected and coordinated. And evidence suggests we can “hack” our smart vagus to voluntarily control our own stress response.⁹


Most of the time, you probably aren’t aware of your own breathing rate, but current research suggests that actively monitoring your respiration can provide substantial health benefits. At a specific breathing rate called the resonant frequency, the respiration and heart rate occur at a common frequency and are exactly in sync with one another.¹⁰


This synchrony helps coordinate various components of the autonomic nervous system, allowing you to better regulate your stress response.¹¹


Overall health of the vagal system is promoted, and HRV is maximized.¹²


Breathing at this slow resonant frequency is associated with multiple health benefits, including reduction of hypertension, asthma, depression, anxiety, and chronic pain.¹³


Biofeedback and Breath Training


What specific techniques are needed to practice resonant-frequency breathing? There are a handful of possible approaches to choose from.


1. Estimate and Experiment


Basic principles of biofeedback can be utilized at home — no fancy equipment needed!


Although individual resonant frequencies may vary, 6 breaths per minute is a very good approximation of the average person’s resonant rate.¹⁴ You’ll need to determine what inhale-exhale ratio you want to use: how much time of each breath will you spend inhaling versus exhaling. Because parasympathetic activity is especially enhanced during exhales¹⁵, many researchers suggest a long-exhale method — such as the 2:8 cycle, with a 2-second inhale and an 8-second exhale¹⁶. Other researchers suggest that an equal 1:1 ratio is the way to go.¹⁷ With this conflicting advice, the best strategy is to try multiple ratios and evaluate which actually feels the best for you.


Convenient mobile apps like iBreathe allow you to set custom inhale-exhale ratios and respiration rates and guide you through practiced breathing sessions.


2. Home Biofeedback Devices


If you want to take your resonance training a step further, consider investing in a home biofeedback device. Small clip-on machines like the Spire take continuous measurements of respiration rate, allowing you to see the results of your breathing patterns in real time.


Many devices can be connected with mobile apps that interpret your measurements, providing personalized feedback and recommendations tailored to your specific needs.¹⁸ One study found that users experienced slight decreases in stress and anxiety levels after beginning the Spire biofeedback program.¹⁹


However, take caution: biofeedback devices are often expensive, and not all of them have been fully validated by scientific evidence. If you decide to purchase one, make sure to actively pay attention to its effects, and return it if it doesn’t make you feel substantially better.


3. Professional Biofeedback Sessions


Finally, the most expensive option: individualized sessions with a biofeedback expert. Therapeutic and clinical providers take specific HRV measurements as you breathe at different respiratory intervals, allowing them to pinpoint your precise resonance frequency and develop a treatment plan.²⁰ Such sessions have proven somewhat successful in treating asthma, high blood pressure, and various mental disorders.²¹


The main drawback?: Accessibility


Few providers offer biofeedback or respiration-control therapy, and it is often expensive and/or not covered by medical insurance.


Controlled respiration is a fascinating area of stress-management research. Resonant breathing is an easy, simple, and quick technique to hack your way towards a lower-stress lifestyle.


Don’t hold your breath — why not give it a try?



Endnotes

1. Flenady, T., Dwyer, T., & Applegarth, J. (2017). Accurate Respiratory Rates Count: So Should You! Australasian Emergency Nursing Journal, 20, 45–47. doi:10.1016/j.aenj.2016.12.003

2. Porges, S. W. (1995). Orienting in a Defensive World: Mammalian Modifications of our Evolutionary Heritage. A Polyvagal Theory. Psychophysiology, 32, 301–318. doi:10.1111/j.1469–8986.1995.tb01213.x.

3. Ibid.

4. Ibid.

5. Ibid.

6. Ibid.

7. Ibid.

8. Porges, S. W. (2007). The Polyvagal Perspective. Biological Psychology, 74(2), 116–143. doi:10.1016/j.biopsycho.2006.06.009

9. Porges (1995)

10. Van Diest, I., Verstappen, K., Aubert, A. E., Widjaja, D., Vansteenwegen, D., & Vlemincx, E. (2014). Inhalation/Exhalation Ratio Modulates the Effect of Slow Breathing on Heart Rate Variability and Relaxation. Applied Psychophysiology and Biofeedback, 39, 171–180. doi:10.1007/s10484–014–9253-x

11. Ibid.

12. Lin, I. M., Tai, L. Y., & Fan, S. Y. (2014). Breathing at a Rate of 5.5 Breaths Per Minute with Equal Inhalation-to-Exhalation Ratio Increases Heart Rate Variability. International Journal of Psychophysiology, 91(3), 206–211. doi:10.1016/j.ijpsycho.2013.12.006

13. Van Diest et al. (2014)

14. Ibid.

15. Lin et al. (2014)

16. Cappo, B. M., & Holmes, D. S. (1984). The Utility of Prolonged Respiratory Exhalation for Reducing Physiological and Psychological Arousal in Non-Threatening and Threatening Situations. Journal of Psychosomatic Research, 28(4), 265–273. doi:10.1016/0022–3999(84)90048–5

17. Lin et al. (2014)

18. Smith, E. N., Santoro, E., Moraveji, N., Susi, M., & Crum, A. J. (2020). Integrating Wearables in Stress Management Interventions: Promising Evidence from a Randomized Trial. International Journal of Stress Management, 27(2),172–182. doi:10.1037/str0000137

19. Ibid.

20. 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. doi:10.1023/a:1009554825745

21. Ibid.