There are two branches of the body’s peripheral nervous system — the sympathetic branch and the parasympathetic branch. The sympathetic branch controls the body’s fight-flight response. This is the response that occurs when we are stressed. The parasympathetic branch, in contrast, is like the braking system on the stress response. It brings the body back to a normal state after the danger has passed. The good news is that we can control the activation of the parasympathetic nervous system and thus control our stress response.
How do we do this? The answer is diaphragmatic breathing. Diaphragmatic breathing is breathing with the abdomen, rather than the chest. This abdomen breathing puts pressure on the body’s longest cranial nerve, called the vagus nerve. Activating the vagus nerve in turn activates the parasympathetic nervous system, and helps to quiet the stress response.