Often in yoga we refer to something called “fight or flight” to account for the mundane worries of the world that may steal our presence during practice.
Fight or flight refers to our sympathetic and parasympathetic nervous systems, which are the “autonomic” nerves to our organs that are believed to be out of our control. It is generally understood that the sympathetic nervous system (SNS) revs us up or excites us, and the parasympathetic nervous system (PNS) revs us down or relaxes us, but there is so much more to it than that.
I would like to talk about the entire nervous system, including the peripheral or “somatic” part that we do control and how it also ties in. My ultimate goal is to (1) explain how yoga and asana integrate with all parts of the nervous system, (2) help you understand why some poses stimulate certain pathways either consciously or subconsciously, and (3) show how to pair the PNS an SNS into a yoga class for those perfect sensations whether you’re shooting for peak asana or something more subtle.
Part 1: Nervous System Integration
The PNS (parasympathetic nervous system) does not inhibit the SNS (sympathetic nervous system), they are both excitatory systems. Ideally, these systems are in balance with each other, one waxing while the other one wanes. The SNS excites us when it is time to fight or flee (heart races, eyes widen and dilate to look out, lungs open up, sphincters close, digestion stops, adrenals release epinephrin, liver calls for energy stores to become sugar) while the PNS excites us to rest and digest (eyes constrict, heart slows, sphincters relax, digestion begins, liver calls to make energy stores). Notice that with each, the organs are being stimulated for a purpose but not two purposes at once. IBS is a problem where a confused gut becomes dually excited, so stress causes a painfully mixed reaction of both PNS and SNS activity.
We can say energetically the SNS is a plus and the PNS is a minus however the minuses don’t turn off pluses and the key to sustainability is balance without extremes. This way we can experience healthful levels of excitation to lift us up while also providing our body with energizing rest that restores us. Unbalanced SNS may drive anxiety or anger and too much PNS may make one lazy or depressed. The demands of the modern world frequently drive us into too much SNS and subsequently we get adrenal fatigue.
There is also the “somatic” nervous system which controls our skeletal muscles and sensations like pain or comfort. It is a bottom up model where our somatics work in concert with our emotions and intelligence to change and modulate the outputs of the autonomics. When properly aligned, or at least comfortable in asana, we lose the over-excitation that comes from the protective need of the PNS or SNS, and this is when we feel yoga relax us into a state of presence where our thoughts and control of wellbeing is not influenced by our external altercations or stimuli. Here we may hypothesize why yoga “miraculously” healed Iyengar and Paramahansa Yogananda. It is also part of the scientific basis for osteopathy whereas other forms of modern medicine try to only adjust outputs to organs and therefore cannot create true natural healing from within.
Part 2: Stimulatory Effects of Poses
Nerves pass up and down through ganglia or “switchboards”. SNS switchboards are located along the thoracic and lumbar spines and is why dancer pose is so exhilarating. PNS switchboards are located at the neck and sacrum and is why child’s pose is so relaxing.
That perfect experience in poses like camel balances both PNS and SNS switchboards by evenly distributing the curve to make us feel proud, strong and energized through the mid-spine while at the same time making us feel relaxed but poised and protected through the neck and pelvic regions. When poses are properly embodied, somatics to the brain speak comfort and we perceive a safe place, the SNS or PNS are balanced and naturally go back and forth between excitatory states without extremes. Extremes overly heighten the system and drive one towards the opposite excitatory state, ie. crunching of the lumbar spine in camel that suddenly drives us into child’s pose, or a pigeon pose that just doesn’t feel accomplished without having to be a mermaid.
Part 3: Pairing of Asana and Flow
As yoga teachers, we must be experts in neuroplasticity and ask ourselves what we want to achieve, and then strategize a practice that uses somatics to balance the body and mind without extremes or drastic autonomic cycling. Yoga thus provides a way for teachers and students to actively remodel how the body handles stress and disease.
All yoga poses have their perfection, but we want to teach to the needs of the students. Compliment sustained flow of poses affect both SNS and PNS equally in turn, but don’t push one system too hard. This creates an enjoyable and sustainable practice. From an anatomical model, movement and engagement in the thoracic and lumbar spines stimulate the SNS more. The PNS is stimulated more through the neck and pelvic regions. Asanas that intensify awareness in these parts of the spine or add rapid cyclic motion to them will heighten the effect, as do focused assists and touch.
Thoughtfully creating your yoga class can involve more than just warming up and stretching the muscles and joints and also include fully balancing the needs of the automatics. Classes that build to those climactic poses do so best though the gradual crescendo of SNS excitation of the thoracic and lumbars without overstimulating a premature collapse into the PNS. Restorative flows can calm us down greatly by stimulating areas of the neck and pelvis. Asanas that go back and forth without pushing one too far gives us something enjoyably and sustainably in between.
In a standard yoga teacher training, you learn how to build heat or create cooling in various intensities, and think ahead as to where and why this is important for the rest of the class. A deeper art is understanding why some poses stimulate certain autonomic pathways either consciously or subconsciously, and how to build flow to pair the pathway for those perfect sensations whether you’re shooting for peak asana or something more subtle. Embodiment that allows the somatics to deliver sensations of safety and wellbeing avoids triggering the protective need of the SNS or PNS. Doing so balances the the SNS and PNS into naturally healthy oscillations of excitation without extremes and is fundamental to helping students truly feel yoga liberated from the instinct of fight or flight.
By Dr. Jonathan Bloch, Blissology 300-hr YTT graduate
Check out Jonathan’s teacher profile to learn more.