Breathwork modulates autonomic arousal
Breathing can be used as a conscious control for influencing the body stress level. By performing deep breathing, one is maximizing the blood oxygen saturation while eliminating most of the carbon dioxide. The body reacts to this highly favorable situation by relaxing on a biochemical level. Conversely, one can hold their breath, and in doing so cause temporary hypoxia, a situation in which cells can’t eliminate carbon dioxide and can’t replenish their oxygen supply. This leads to an increase in stress on a biochemical level, and by extension to a state of high autonomic arousal.