At one time or another we have likely all experienced a stitch in our side, that sharp pain or spasm in the upper part of the belly that occurs during exercise. But even with the frequency of this problem, its cause is poorly understood. A number of theories have been proposed to explain why people get stitches in their side, but the most widely accepted theory involves inadequate blood flow to the muscles between the ribs and the diaphragm below the lungs. During exercise, a greater percentage of blood flows to the large muscles of the legs and arms, resulting in these respiratory muscles having to do more work at breathing with less oxygen supply from blood. This may cause the painful stitches that we experience, usually just under our ribs. So, just like a lack of blood supply to the heart causes a heart attack, a lack of blood supply to the diaphragm and the rib muscles may cause a stitch in our side, or might we now call it a rib muscle attack.
