Category Archives: Yoga Gem

To say that yoga simply relaxes the nervous system is an oversimplification. Many yogic practices, like backbends and strong pranayama techniques, actively stimulate the SNS, so yoga’s benefits can’t be reduced to just relaxation. What you want is an ANS that’s finely tuned to respond to whatever stresses life brings, shifting the relative activation of the PNS and SNS as needed. My guess is that yoga, by a combination of stimulating and relaxing practices, tones the nervous system to give it this flexibility. Researchers analyze the function of the ANS by looking at such factors as how well the body senses and adjusts to changes in body position (baroreceptor sensitivity) and whether the heart maintains a healthy though subtle variation in its rhythm (heart rate variability). Yoga appears to improve both of these measures. (source: Timothy McCall, M.D.)

When people talk about stress reduction, they often mean changing the balance between the two branches of the autonomic nervous system (ANS), switching it from a hyper-vigilant state, mediated by the sympathetic nervous system (SNS), to relaxation, mediated by the parasympathetic nervous system (PNS). The ANS regulates the function of internal organs such as the heart, lungs, and intestines; it is sometimes dominated by the SNS and sometimes by the PNS, depending on the circumstances. The SNS, the “fight or flight” response, becomes more dominant in emergencies. When there is now perceived emergency, the PNS dominates. The PNS is calming and restorative; it lowers the breathing and heart rates, decreases blood pressure, and increases blood flow to internal organs such as the intestines and reproductive organs, allowing you to “rest and digest.” These effects, which are the opposite of fight-or-flight, constitute what Dr. Herbert Benson has dubbed “the relaxation response.” The system he popularized to elicit it, which involves closing the eyes, following the breath, and repeating a word or phrase, is directly modeled on Transcendental Meditation (TM), a type of yogic mantra meditation, though other yogic tools including asana and pranayama can similarly shift stress in a wide variety of medical problems – not just the obvious ones like migraines and insomnia. (source: Timothy McCall, M.D.)