Deep breathing has become increasingly important in my recovery from depression and anxiety because I recognize that shallow breath contributes to my panic. In fact, at my worst hours, I would use a paper bag to keep from hyperventilating.
The practice of deep breathing stimulates our parasympathetic nervous system (PNS), responsible for activities that occur when our body is at rest. It functions in opposite to the sympathetic nervous system, which stimulates activities associated with the flight-or-fight response. I like to the think of the PNS as the calm sister and the sympathetic nervous system as the non-sympathetic crazy sister on the verge of a nervous breakdown. You know that woman in the movie “Airplane” that’s wigging out (watch this clip), and there is a line behind her of people with weapons saying “Get a hold of yourself.” The woman represents the sympathetic nervous system, and the long line of folks with bats, ropes, purses, etc. are members of the parasympathetic nervous system trying to calm the panicked passenger.