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Six per minute non-invasive ventilation: Resonant Frequency breathing for COVID-19?
by David Lowenfels, M.Eng., M.A. Author correspondence: david.lowenfels@gmail.com
May 28, 2020 (v4)
Intrinsic neurovascular oscillations near 6 per minute have essential regulatory functions for
physical and mental health [Schwerdtfeger 2019]. A respiratory rate (RR) near six breaths per
minute amplifies this inner rhythm, creating a zone of metabolic efficiency and perfect
sympathovagal balance -- neither relaxation nor fight-or-flight. So-called “resonant frequency”
(RF) breathing is a periodic (session-based) intervention that strengthens autonomic balance
and neurovisceral integration. Over 30 years of clinical studies on RF breathing demonstrate the
ability to cultivate resilience against stress, reduce inflammation, and increase pulmonary gas
exchange efficiency [2014 Lehrer & Gevirtz]. These beneficial effects are understood to be due
to neuromodulation of the baroreflex, vagus nerve, and related neuro-endocrine and
neuro-immune axes.
The autonomic nervous system could be seen as the organizing agent of “vital force” that
regulates survival, adaptability, and well-being. From another perspective it is the gestalt of
information/energy flow between localized and systemic intelligences. A major information
superhighway that mediates this flow is the vagus nerve, which threads its way between the
viscera (gut feelings), the brain stem (autonomic reflexes), the limbic system (environmental
safety and socio-emotional function), and the prefrontal cortex (cognitive/executive function).
Due to the promotion of neurovisceral integration, short daily periods of RF breathing seem to
be a veritable panacea, with positive effects on a wide array of conditions ranging from
hypertension, anxiety, depression, and PTSD, to irritable bowel syndrome, chronic pain,
asthma, and inflammation. My hypothesis is that RF breathing could be a helpful early
intervention for COVID-19, perhaps preventing further decline due to vascular and inflammatory
complications. With poor outcomes due to lung damage, doctors are now delaying invasive
endotracheal ventilation, and instead opting for high-flow oxygen and CPAP [2020 Gessman]. I
would like to highlight the potential of BiPAP S/T to mechanically pace RF breathing [2017
Schmidt et al.]. HEPA filters can be added in-line to prevent the generation of infectious
aerosols [2020 Gessman].
With the recent push to develop low-cost open source ventilators, I investigated the design and
was surprised to learn that the controlled RR does not go below 15 breaths per minute. In my
studies on volitional breathing techniques, I learned that the state of the autonomic system can
be manually controlled by RR, with approximately six per minute being the zone of perfect
sympathovagal balance. Slower (e.g. three per minute) drives parasympathetic activity, and
faster (e.g. 30-60 per minute) drives sympathetic activity. According to this understanding,
patients on artificial ventilation would be in a sympathetic overdrive with resulting
parasympathetic withdrawal -- presumably not the best zone for fully resourced healing and
recovery.
I hold hardware/software engineering degrees from MIT and Stanford, and many certifications in
body-mind and manual therapies. For the last five years I have been deeply investigating Heart
Rate Variability (HRV) biofeedback and its neurophysiologic mechanisms [2017 Lowenfels].
HRV Biofeedback was developed in the 90's as a noninvasive therapy for cognitive and
physiological disorders of the autonomic system. Extensive research has since shown a myriad
of positive effects on mind, body, and emotion [2013 Gevirtz, 2014 Leher & Gevirtz], which may
be unified by the vagus nerve and the Neurovisceral Integration Model [review with 2018
Laborde et al.]
The crux of HRV biofeedback is controlled respiration near six breaths per minute. This creates
a respiratory cycle that strongly flexes the autonomic system between parasympathetic and
sympathetic with each breath -- baroreflex circuit resonance drives maximum respiratory sinus
arrhythmia (RSA, i.e. vagal-associated HRV) which strongly oscillates vascular tone, heart rate,
and blood pressure. Gas exchange in the lungs is enhanced due to the inverted phase
synchronization of RSA with blood pressure cycles: peak inspiration at blood pressure minima,
and peak exhalation at blood pressure maxima. At this resonant frequency, the perfect balance
of relaxation and alertness recharges the homeostatic function, optimizes neurovisceral
integration, promotes efficient pulmonary gas exchange, reduces pain perception, stimulates
anti-inflammatory reflexes, and enhances resilience to physical and emotional stressors.
For these reasons, I propose the study of six per minute ventilation on COVID-19 patients.
This can be done non-invasively through a BiPAP S/T, or even through a paced audio
soundtrack. Since HRV biofeedback is practiced for short periods of 20 minutes daily, with good
results, all-day respiration at RF is not necessary (and may result in blood gas disturbances). I
propose to begin investigation with two or three sessions of 15 minutes, daily.
Because not all individuals have a RF at six per minute (some are faster or slower) [2006
Vaschillo et al.], it would be ideal to use an instantaneous (not averaged) heart rate sensor to
determine an individual's actual RF. I hold a patent filing on a closed-loop system to
automatically determine RF, however it can be done manually by a short sequence of trial and
error.
It may turn out that this intervention is most appropriate for prevention rather than emergency
treatment. Since I am not a clinician, I welcome critique and input from those who have such
experience. Please share this document with frontline clinicians and other scientific colleagues
that might be interested in this topic. I am open to learn, collaborate, and contribute my
cross-disciplinary expertise. Essential literature is referenced below.
Sincerely,
David Lowenfels
https://www.linkedin.com/in/david-lowenfels
david.lowenfels@gmail.com
Bibliography:
2020 Gessman "How to add hepa filters to CPAP machines for use in the covid 19 epidemic”
https://www.youtube.com/watch?v=xC6LRNm7CAU
2017 Lowenfels "David Lowenfels - Enhancing Performance through HRV - Consciousness
Hacking", https://www.youtube.com/watch?v=lvb7IdhT48c
2017 Schmidt et al. "The effects of slow-paced versus mechanically assisted breathing on
autonomic function in fibromyalgia patients" http://doi.org/10.2147/JPR.S139642
(CPAP at 6 per minute to promote baroreflex resonance breathing in patients with fibromyalgia)
2004 Moss, "Heart rate variability and biofeedback".
https://www.researchgate.net/publication/259560433
"Heart rate variability (HRV) is a critical marker of a healthy organism. Low HRV predicts greater
morbidity and mortality after heart attack, and also predicts death by all causes. HRV
biofeedback can increase the adaptive and coherent variability in heart rate, and moderate the
symptoms of asthma, COPD, and other autonomically mediated medical conditions."
"This 0.1 Hz frequency is most frequently produced by persons in a relaxed mental state, with a
positive emotional tone, breathing diaphragmatically at a rate of about 5-7 breaths per minute.
Relaxed breathing at six breaths per minute produces a spike of heart rate variability at 0.1 Hz.
Remember that one tenth of a Hertz equals one tenth of a cycle per second, so that 0.1 Hz
equates mathematically to six cycles per minute. The other measures of HRV also tend to
maximize when heart rate change is dominated by rhythms in this Low Frequency range. The
amplitude of variation is higher, because the effects of the baroreceptors on heart rate are
added to the effects of slow breathing on heart rate."
2014 Lehrer & Gevirtz "Heart rate variability biofeedback: how and why does it work?"
http://doi.org/10.3389/fpsyg.2014.00756
"Respiratory Sinus Arrhythmia controls the rate of gas exchange at the alveoli, such that heart
rate tends to be higher when air in the lung is richest in oxygen, and exhalation occurs when
carbon dioxide in the lung is highest"
2017 de Bruin et al. "A RCT Comparing Daily Mindfulness Meditations, Biofeedback Exercises,
and Daily Physical Exercise on Attention Control, Executive Functioning, Mindful Awareness,
Self-Compassion, and Worrying in Stressed Young Adults"
http://doi.org/10.1007/s12671-016-0561-5
(HRV Biofeedback has mental stress benefits equal to exercise and meditation)
2001 Purcell et al. "Brief resonance frequency training can reduce C-reactive protein levels in
normals" [Poster Abstract]
(Brief resonance training significantly reduces CRP)
2017 Steffen et al. "The Impact of Resonance Frequency Breathing on Measures of Heart Rate
Variability, Blood Pressure, and Mood" http://doi.org/10.3389/fpubh.2017.00222
(Resonant frequency breathing had more positive outcomes than faster (RF+1) or control)
2006 Vaschillo et al. "Characteristics of Resonance in Heart Rate Variability Stimulated by
Biofeedback" http://doi.org/10.1007/s10484-006-9009-3
Review Papers
2013 Gevirtz "The Promise of Heart Rate Variability Biofeedback: Evidence-Based Applications"
http://doi.org/10.5298/1081-5937-41.3.01
2018 Laborde et al. "A unifying conceptual framework of factors associated to cardiac vagal
control" http://doi.org/10.1016/j.heliyon.2018.e01002
(Review on the Neurovisceral Integration Model how cardiac vagal control is central to physical,
emotional, and cognitive health and disease)
2018 Gerritsen & Band "Breath of Life: The Respiratory Vagal Stimulation Model of
Contemplative Activity" http://doi.org/10.3389/fnhum.2018.00397
2019 Schwerdtfeger et al. “Heart Rate Variability (HRV): From brain death to resonance
breathing at 6 breaths/minute” http://doi.org/10.1016/j.clinph.2019.11.013
HRV-BF reduces blood pressure, stress reactivity, enhances mood - more
effective than simple deep breathing
- Steffen et al. (2017). The Impact of Resonance Frequency Breathing on Measures of Heart Rate Variability,
Blood Pressure, and Mood. Frontiers in Public Health. doi:10.3389/fpubh.2017.00222
HRV-BF equally as effective as exercise or mindfulness meditation
- van der Zwan et al. (2015). Physical activity, mindfulness meditation, or heart rate variability biofeedback for
stress reduction: a randomized controlled trial. Applied Psychophysiology and Biofeedback.
https://doi.org/10.1007/s10484-015-9293-x
HRV-BF for stress & anxiety: 2x more effective than relaxation
- Lee et al. (2015). The benefit of heart rate variability biofeedback and relaxation training in reducing trait
anxiety. Hanguk Simni Hakhoe Chi Kongang. PMID: 27099546.
- Goessl et al. (2017). The effect of heart rate variability biofeedback training on stress and anxiety: a
meta-analysis. Psychological Medicine. doi:10.1017/s0033291717001003
HRV-BF for Hypertension
- Koichubekov & Sorokina (2015). P-217: Effect of heart rate variability biofeedback on brain electrical activity
in stage I hypertensive patients. Annales de Cardiologie et d’Angéiologie.
doi:10.1016/s0003-3928(16)30259-1
- Lin et al. (2012). "Heart Rate Variability Biofeedback Decreases Blood Pressure in Prehypertensive Subjects
by Improving Autonomic Function and Baroreflex." The Journal of Alternative and Complementary Medicine.
doi:10.1089/acm.2010.0607
- Chen at al. (2015). “Effects of heart rate variability biofeedback on cardiovascular responses and autonomic
sympathovagal modulation following stressor tasks in prehypertensives.” Journal of Human Hypertension.
doi:10.1038/jhh.2015.27
related: Device-guided breathing reduces blood pressure
- Brook et al. (2013). "Beyond Medications and Diet: Alternative Approaches to Lowering Blood Pressure A
Scientific Statement From the American Heart Association” (summary on p.1370)
doi:10.1161/HYP.0b013e318293645f
- RESPeRATE is a device-guided breathing that is FDA approved as adjunctive therapy for blood pressure
reduction https://www.resperate.com/about-us
HRV-BF reduces inflammation
- Nolan et al. (2012). "Behavioural modification of the cholinergic anti-inflammatory response to C-reactive
protein in patients with hypertension." Journal of Internal Medicine. doi:10.1111/j.1365-2796.2012.02523.x
- Purcell et al. (2011). Brief resonance frequency training can reduce C-reactive protein levels in normals
[Abstract]. Poster presented at the meeting of the Association for Applied Psychophysiology and
Biofeedback, New Orleans, Louisiana.
http://fshaffer.sites.truman.edu/files/2011/06/Truman-Research-Team-Abstracts-1991-2011.pdf
- Lehrer et al. (2010). Voluntarily Produced Increases in Heart Rate Variability Modulate Autonomic Effects of
Endotoxin Induced Systemic Inflammation: An Exploratory Study. Applied Psychophysiology and
Biofeedback. doi:10.1007/s10484-010-9139-5
- Thayer et al. (2011). Inflammation and cardiorespiratory control: The role of the vagus nerve. Respiratory
Physiology & Neurobiology. doi:10.1016/j.resp.2011.05.016
HRV-BF for cardiac disease - improved prognosis, reduced hospitalization,
mortality, depression and hostility
- Yu et al. (2017) "One-Year Cardiovascular Prognosis of the Randomized, Controlled, Short-Term Heart Rate
Variability Biofeedback Among Patients with Coronary Artery Disease” doi:10.1007/s12529-017-9707-7
- Lin et al. (2015) "Randomized controlled trial of heart rate variability biofeedback in cardiac autonomic and
hostility among patients with coronary artery disease." doi:10.1016/j.brat.2015.05.001
- Gevirtz (2013). “The Nerve of That Disease: The Vagus Nerve and Cardiac Rehabilitation. Biofeedback."
doi:10.5298/1081-5937-41.1.01
HRV-BF for chronic pain
- Wilson (2017). Heart Rate Variability Biofeedback Training as an Intervention for Chronic Pain.
https://epublications.marquette.edu/dissertations_mu/739/
- Tracy et al. (2017). Heart Rate Variability and Sensitivity to Experimentally Induced Pain: A Replication. Pain
Practice. doi:10.1111/papr.12652
- Berry et al. (2014). Non-pharmacological Intervention for Chronic Pain in Veterans: A Pilot Study of Heart
Rate Variability Biofeedback. Global Advances in Health and Medicine doi:10.7453/gahmj.2013.075
- Hallman et al. (2011). Effects of Heart Rate Variability Biofeedback in Subjects with Stress-Related Chronic
Neck Pain: A Pilot Study. Applied Psychophysiology and Biofeedback. doi:10.1007/s10484-011-9147-0
- Sowder et al. (2010). Restoration of Vagal Tone: A Possible Mechanism for Functional Abdominal Pain.
Applied Psychophysiology and Biofeedback. doi:10.1007/s10484-010-9128-8
- De Couck et al. (2014). You May Need a Nerve to Treat Pain. The Clinical Journal of Pain.
doi:10.1097/ajp.0000000000000071
HRV-BF for insomnia
- Acker et al. (2017). Handheld mobile biofeedback of heart rate variability in patients with chronic insomnia
disorder – a pilot study. Sleep Medicine. doi:10.1016/j.sleep.2017.11.007
- Tsai et al. (2014). Efficacy of paced breathing for insomnia: Enhances vagal activity and improves sleep
quality. Psychophysiology. doi:10.1111/psyp.12333
HRV-BF for depression
- Lin et al. (2019). Heart rate variability biofeedback increased autonomic activation and improved symptoms
of depression and insomnia among patients with major depression disorder. Clinical Psychopharmacology
and Neuroscience. doi:10.9758/cpn.2019.17.2.222
- Caldwell & Steffen (2018). Adding HRV biofeedback to psychotherapy increases heart rate variability and
improves the treatment of major depressive disorder. International Journal of Psychophysiology.
doi:10.1016/j.ijpsycho.2018.01.001
- Siepmann et al. (2008). A pilot study on the effects of heart rate variability biofeedback in patients with
depression and in healthy subjects. Applied Psychophysiology and Biofeedback.
doi:10.1007/s10484-008-9064-z
- Karavidas et al. (2007). Preliminary results of an open label study of heart rate variability biofeedback for the
treatment of major depression. Applied Psychophysiology and Biofeedback. doi:10.1007/s10484-006-9029-z
HRV-BF for cognitive function
- Jester et al. (2018). Heart rate variability biofeedback: implications for cognitive and psychiatric effects in
older adults. Aging & Mental Health. doi:10.1080/13607863.2018.1432031
- Prinsloo et al. (2013). The effect of a single session of short duration biofeedback-induced deep breathing
on measures of heart rate variability during laboratory-induced cognitive stress: A pilot study. Applied
Psychophysiology and Biofeedback. doi:10.1007/s10484-013-9210-0
