In part 1 of this article [April issue], I explored slow, lower abdominal breathing from the perspective of Chinese medicine. By descending the breath to the dantian, we can lower heart fire into the cooling embrace of kidney water, nourish our deepest energies, and calm and stabilize the shen.

Now let's discuss some of the science of slow breathing, looking at nasal breathing, carbon dioxide and the autonomic nervous system.

Nasal Breathing

Nitric oxide (1992's "molecule of the year"!) is found in some foods (for example, dark, leafy vegetables, beetroot and walnuts). Its production in the body is stimulated by exercise and sunlight, and it is produced in the paranasal sinuses and absorbed when we inhale through the nose (but not the mouth).¹

Nitric oxide opens the airways and blood vessels (bronchodilation and vasodilation), thus increasing oxygenation, lowering blood pressure and enhancing blood flow to the brain, muscles and genitals. Both nitroglycerin (angina) and Viagra-type drugs act via the NO₂ pathway.

Interestingly the production of NO₂ is increased 15-fold when we hum (vibrating the sinuses) vs. when we inhale through the nose.²

Carbon Dioxide

If we ask people to breathe deeply, they usually take big and/or rapid upper-chest breaths. Paradoxically, this doesn't increase oxygenation, but rather reduces carbon dioxide (CO₂). The effect can be an increase in levels of anxiety, stress and chest tightness.

Blood vessels constrict, blood pressure rises and blood flow to the brain is reduced (affecting judgment and concentration). When extreme, it can lead to or worsen panic attacks, for which the folk remedy is to breathe in and out of a paper bag to restore CO₂ levels.

However, when we practice breathing deeply and slowly into the lower abdomen, we can train ourselves to resist the chemoreflex response to low levels of CO₂ (which normally triggers inhalation), thus increasing levels in the blood significantly.³ The effect of this increase in CO₂ is to open the airways of the lungs and dilate blood vessels throughout the body (including in the lungs), resulting in increased oxygenation, lower blood pressure and increased blood flow to the brain.

The Autonomic Nervous System

The autonomic nervous system (ANS) is an almost-too-perfect example of yinyang. The yang sympathetic ("fight or flight") branch (SNS) is part of our ancient defense mechanism. It is activated in times of threat and triggers a host of physiological responses. Most blood vessels contract, our pupils dilate, blood pressure, breathing and heart rate increase, and we become hyperalert.

We can also enter SNS dominance at will, seeking excitement and stimulation by engaging in dangerous sports or high-intensity physical training, watching scary movies or thrilling football matches, and so on.

Vital (or enjoyable) as these responses may be, we need to be able to switch off sympathetic dominance when the danger or stimulation has passed. SNS activation burns energy in cells, and if prolonged can give rise to long-term cellular inflammation, which we now understand to underlie many chronic diseases. And if it becomes our default state, it can lead to ingrained feelings of stress, tension, fear, worry, defensiveness, inability to be emotionally close, PTSD, and poor judgment and reasoning.

By contrast, when we are in a yin parasympathetic (PNS) "rest, relax, digest" state, our blood vessels dilate and relax, heart rate and blood pressure drop, our immune system is enhanced, our energy reserves are restored and anti-inflammatory pathways are activated to counter the inflammatory effects of SNS activation. Our mind and body are calmed and we spontaneously enjoy feelings of safety, trust, intimacy and enhanced "flow states."

Enhancing PNS (Yin) States: The Power of Proper Breathing

While we know that practices such as meditation and relaxation enhance PNS states, it now appears that the swiftest, most reliable and most accessible way is slow, deep, lower abdominal breathing, which strongly descends the diaphragm and stimulates the vagus nerve.⁴

American psychiatrist Stephen Porges, in his (not uncontroversial) polyvagal theory, proposes that the higher mammals, especially humans, have evolved a third and more sophisticated defense mechanism (after the oldest reptilian "freeze" and the later "fight or flight" responses), which is the ability to transmit and read messages of safety and trustability, enabling us to work and cooperate in small and large groups.

He proposes that branches of the vagus nerve travel to the facial muscles, larynx and ears, and our degree of trustability is reflected in our facial expression, the volume and cadence of our voice, and our ability and willingness to listen. Whether or not the polyvagal theory is correct, this seems to match our everyday human experience.⁵

Significance for Your Patients and Practice

The significance for practitioners is that if we are in a genuine (not "fake"), open and friendly PNS state, we are transmitting strong messages of safety and trustability to our patients, many of whom may be locked in SNS dominance and have no other relationship in their life that offers this gift.

So, how do we practice the kind of breathing that offers such healing benefits to ourselves and those with whom we come in contact? The answer, according to an ever-growing body of research, is what has been termed coherent breathing, i.e., breathing at a rate of around six breaths (= six inhalations and exhalations) a minute. This shifts us into a deep PNS state with all the benefits that brings, including lowering blood pressure, easing pain and maximizing beneficial heart rate variability and respiratory sinus arrhythmia (both indications of healthy physiology).⁶

I practice and teach qigong, in which slow movements naturally integrate with slow breathing at a coherent rate. But whether in the context of qigong, yoga or simply standing, seated or lying-down slow breathing practice, we have a tool that can make a profound difference to our own mental, emotional and physical state. It can also radiate to our patients and – if we have sincerely practiced ourselves – is something we can teach them and thus spread the benefit ever outward into the world.

References

1. Lundberg JO, et al. High nitric oxide production in human paranasal sinuses. Nat Med, 1995 Apr; 1(4):370-3.
2. Weitzberg E, Lundberg J. Humming greatly increases nasal nitric oxide. Am J Respir Crit Care Med, 2002;166(2):144-5.
3. Bernardi L, et al. Slow breathing reduces chemoreflex response to hypoxia and hypercapnia, and increases baroreflex sensitivity. J Hypertens, 2001;(12):2221-9.
4. Pal GK, Velkumary S et al. Effect of short-term practice of breathing exercises on autonomic functions in normal human volunteers. Ind J Med Res, 2004;120(2):115-21.
5. Porges S. The polyvagal theory: new insights into adaptive reactions of the autonomic nervous system. Cleve Clin J Med, 2009;76(Suppl 2):S86–S90.
6. Brown R, Gerbarg P. The Healing Power of the Breath: Simple Techniques to Reduce Stress and Anxiety, Enhance Concentration, and Balance Your Emotions. Trumpeter Books, 2012.

Peter Deadman has worked with Chinese medicine and health promotion for more than 45 years. He is the founder of the Journal of Chinese Medicine, co-author of A Manual of Acupuncture and author of Live Well Live Long: Teachings From the Chinese Nourishment of Life Tradition. He is also an international qigong lecturer and teacher. He can be contacted at: .