WITH YOU, I BREATHE: A forty day yoga column
#16: More about the Nervous System
The autonomic nervous system is part of our nervous system that controls a lot unconscious activity in the body, as well as internal organs. The autonomic nervous system takes part in: sexual arousal, heart rate, digestion, salivation, contraction and dilation of the pupils, urination, defecation. The sympathetic nervous system and parasympathetic nervous are part of the autonomic system and tend to work in opposite ways. Oftentimes people describe the sympathetic nervous system as our “fight or flight” response, whereas our parasympathetic nervous system is our “rest and digest” response.
Depending on our circumstances and state of mind, one is active and the other, for the most part, remains inactive. In highly stressed situations, our sympathetic nervous system activates, and the pupils will dilate, the heart rate increases, and saliva decreases. In relaxed situations, the parasympathetic nervous system activates, and the pupils constrict, the heart rate decreases, and saliva increases.
Most of this activity is unconscious because most of the autonomic nervous system functions at an unconscious level. However, you can activate the parasympathetic nervous system with the breath, specifically with a deep breath.
During yoga classes, many teachers guide the class to length the inhale and the exhale and encourage students to remain conscious of the breath during poses, especially during challenging poses. When the yoga student focuses on the breath, he will activate the parasympathetic nervous, which is a large part of the reason he will feel relaxed during and after class.