The Neurophysiology of Pranayama and Its Effects
*this was originally published in 2016, then again in 2019 for Tap In Meditation. A version of this essay was published in The Book of Handstands, by Holly Fiske.
In today’s culture, some of the hottest topics are meditation, yoga and neuroscience. How these topics overlap is my life’s work. It is not uncommon for one to hear mention of the brain and the nervous system in a given meditation. In meditation & yoga, we are asked to feel, notice or regulate our breath. We are often told that these are the practices of modulating the nervous system. But what does that really mean? Here is the nutshell answer, in 1000 words or less.
Our autonomic nervous system is the component of our nervous system that regulates all bodily functions, typically without our conscious awareness. However, the practice of yoga consciously cultivates this awareness with the incredible tool of the breath. The breath is the most consciously accessible autonomic function. Just as the nervous system dictates the breath, when we dictate the breath, we dictate the nervous system. Everything is a two-way street. Within our autonomic nervous systems, there are two branches, which too are growing rapidly as discussions within our culture. The sympathetic nervous system is commonly referred to as the “fight or flight” response. The parasympathetic is the “rest and digest” response. We were once afraid of saber-tooth tigers and are now fearful of deadlines and speeding taxis. This is when we need our sympathetic nervous system: to survive in the face of danger or perceived threat. Thus, psychological stress is processed in the exact same way by the nervous system as the stress of running for your life. However, this is truly the main function of the sympathetic nervous system. It shuts off function to all the major visceral organs: immune, endocrine, digestive, reproductive systems are all shut off. Therefore, living in the sympathetic nervous system is not only unsustainable but detrimental to health in the long run. The parasympathetic nervous system is responsible for your growth, development, and general functioning as an organism. Thus, it is imperative to live in parasympathetic dominance more frequently than sympathetic. The two systems are inverse functions but existence is rarely purely one or the other, rather one is simply dominant. Yoga is essentially a practice in establishing and maintaining parasympathetic dominance, and it all comes down to the breath.
The major nerve responsible for virtually all visceral organ function is the vagus nerve, the tenth cranial nerve that travels all the way down into the abdomen. The vagus nerve is a parasympathetic nerve and the tone of the nerve is directly associated with parasympathetic dominance. The vagus nerve controls the parasympathetic activity of the heart, lungs, diaphragm, and digestive organs. Thus, interfacing with the breath means interfacing with the vagus nerve and therefore the parasympathetic nervous system. Ujjayi breathing is the most understood pranayama in the neuroscientific literature. Ujjayi means victorious, which seems fitting for its powerful nature. Ujjayi breathing is created by a slight constriction of laryngeal muscles with partial closure of the glottis, creating an oceanic-like sound. This creates airway resistance during the intake and expiration of breath. The inspiratory loading task activates the somatosensory vagal afferents in the glottis, pharynx, abdominal viscera, and baroreceptors, or the stretch receptors of the lungs and chest wall. This resistive loading task results in strong vagal tone and reduces heart rate. Ujjayi breathing alone has been documented numerous times to produce this parasympathetic dominance. What’s even more fascinating is that in studies comparing the efficacy of pranayam (breath practices) versus asana (physical postures), the yoga practice without ujjayi was significantly less effective than when the breathing practice was added. In studies of veterans with PTSD, they performed asana for depression and anxiety as prescribed by Iyengar in Light on Yoga. This practice did indeed reduce their subjective levels of depression and anxiety, but did not decrease their physiological symptoms of hyperarousal. Only once the pranayama was added did the studies observe significant reductions in markers of stress.
So what can you do to modulate your nervous system on a moment-to-moment basis? Breathe! Studies have also found that regulating the rate of inhale and exhale was equally as effective as ujjayi exhales.
So what can you do to modulate your nervous system on a moment-to-moment basis? Breathe! Studies have also found that regulating the rate of inhale and exhale was equally as effective as ujjayi exhales. So, if you’re having trouble getting ujjayi down, no worries, just try to make the rate and depth of your inhales and exhales match up to the best of your ability.
If you want to practice ujjayi breath, bring your hand up to your mouth and exhale into your hand like you were trying to fog up a mirror, trying to make it very steamy. Try that a few times, breathing in through the nose, then remove your hand, close your lips, and try again. Now it’s as if the mirror you were trying to fog up were right behind your nose. Try that a few times, then try to slow it down. Once you’ve gotten the ujjayi exhale down, try to inhale through the same path of resistance. Once that feels comfortable, you now have some choice. Breathe in through the nose, but for the exhale, tune into how you are feeling. If you feel any pressure build up behind the exhale, then let it out the mouth, as roaring as need be. If you feel no pressure around the exhale and you feel like you have some space, then regulate the exhale out the nose. Either way, use your new skill of ujjayi’s resistive loading.
Every moment of your day is an opportunity to breathe consciously and modulate your nervous system, so you can live in the calm yet alert state of parasympathetic dominance.
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References:
Brown, Richard P. and Gerbarg, Patricia L. “Sudarshan Kriya Yogic Breathing in the Treatment of Stress, Anxiety, and Depression: Part I — Neurophsysiologic Model.” The Journal of Alternative and Complementary Medicine, 11(1): 189–201. 2005.
Gard, Tim, et al. “Potential self-regulatory mechanisms of yoga for psychological health.” Frontiers in Human Neuroscience, 8. 2014 Sep.
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