Deep breathing can do more than just stimulate the parasympathetic nervous system in the midst of a stressful moment; it can prevent your stress response from overacting in the first place.
https://www.thecut.com/2018/12/what-dee ... -body.html
For those of you who do not want to invest hours in obscure systems of Chinese arm waving, but would like to benefit from the possibilities of breath mastery.
Deep Breathing, Vagus Stimulation, and Parasympathetic Nervous System
Deep Breathing, Vagus Stimulation, and Parasympathetic Nervous System

"Prepare your hearts as a fortress, for there will be no other." -Francisco Pizarro González