Diaphragm activates parasympathetic system

Two thirds of breathing takes place by the movement of the diaphragm and only one third by the expansion of the rib cage. Under stressful situations, most people breathe from the chest and do not use their diaphragm. Both laughter and yogic breathing exercises are intended to stimulate the movement of the diaphragm and the abdominal muscles.

The diaphragm is connected to a special branch of the autonomic nervous system called the parasympathetic system or the calming branch responsible for relaxation. The opposite of this is the sympathetic system, also known as the stress arousal system. One can turn off the stress arousal system simply by learning to move the diaphragm. In Laughter Yoga we are training our diaphragm and abdominal muscles to stimulate the parasympathetic system.