How Yoga, Pranayama, and Meditation Cause relaxation and impact blood pressure and anxiety?
Yoga, pranayama, and meditation induce a state of "energized relaxation" by affecting the nervous system. Two of the main branches of the nervous system are known as the sympathetic nervous system and the parasympathetic nervous system.
The sympathetic nervous system controls activities beyond the repertoire of our conscious control; concerned most with the mechanisms of assisting the body to adapt to any stressor. It causes vasodilation of blood vessels and dilation of smooth muscles such as airways and bronchioles.
The parasympathetic nervous system controls activities of the organs themselves, also beyond our conscious control: such as peristalsis, activities of liver, gastric secretions, etc.
Scientific study of the effects of breathing techniques and meditation has demonstrated that the mind can indeed exert control over those processes thus far deemed only under the rulership of the nervous system.
The effects of breathing demonstrate how the autonomic nervous system, that which is ordinarily beyond our influence, can actually brought under conscious control. For example, when we choose to implement breathing techniques, that in turn can affect the sympathetic system by decreasing heart rate and vice versa. If we breathe erratically or labored it can overstimulate the sympathetic nervous system and cause heart rate to increase.
When we exercise, this causes an increase in the demand for oxygen; this causes the sympathetic part to increase heart rate, dilate airways, etc. When we relax, the sympathetic control subsides and the parasympathetic part is more in control so that heart rate is decreased and blood pressure is lowered.
