The diaphragm is a large, fan-shaped muscle that separates the thoracic cavity (above the diaphragm) from the abdominal cavity (below the diaphragm). Most people breath superficially, using only the thoracic cavity.
Diaphragmatic (or abdominal) breathing uses the full capacity of the lungs, allowing for about seven times more oxygen. This produces several benefits on a physical and psychological level - namely, it stimulates the relaxation response, decreasing the anxiety level.
In diaphragmatic breathing:
- when the person inhales, the diaphragm moves downwards, becoming almost flat (decreasing air pressure in the lungs and pulling air inward) and the abdomen moves outwards;
- When the person exhales, the diaphragm moves upward, resembling a cone (increasing the air pressure in the lungs and pushing the air out), and the abdomen moves inward.