Side stitch

Side stitch (also called a side ache, a side cramp, a side crampie, a side sticker or simply a stitch) is an intense stabbing pain under the lower edge of the ribcage that occurs while exercising. It is also referred to as exercise related transient abdominal pain (ETAP). Some people think that this abdominal pain may be caused by the internal organs (like the liver and stomach) pulling downwards on the diaphragm, but that theory is inconsistent with its frequent occurrence during swimming, which involves almost no downward force on these organs. If the pain is present only when exercising and is completely absent at rest, in an otherwise healthy person, it is benign and does not require investigation. There are a variety of published ways of alleviating the symptoms including adjusting at what point in your stride you inhale.

Causes
There are other theories regarding side stitches than simple stretching of the visceral ligaments due to repeated vertical translation and jolting. Such theories include:


 * 1) The pain may be caused by contracting  the liver or spleen, which squeeze extra oxygen-carrying red blood cells into the circulation. Although there does not appear to be much muscle in the capsule of the spleen, there is direct and indirect evidence that its size does change with exercise.  (see ref** below)  This autotransfusion, (which is much larger in some animals) increases exercise capacity but the associated pain may be severe, relieved only by rest. A plausible mechanism for the pain is that high internal pressure in the liver or spleen restricts blood flow, causing hypoxia.
 * 2) Diaphragmatic Ischemia
 * 3) Imbalances of the thoracic spine
 * 4) Irritation of the parietal peritoneum
 * 5) Strain on visceral ligaments by a fluid-engorged gut.
 * 6) Shallow breathing

The reasons for the variety of theories include, in particular, the prevalence of ETAP during swimming.

Most of the time, side stitches occur on the right side of the body. This may be because the largest organ in the abdominal cavity, the liver, is on that side. Certain athletes also report a pain in the tip of their shoulder blade. This is believed to be because this is a referred site of pain for the diaphragm via the phrenic nerve. When the side stitch is on the right side, published advice is to try to exhale when your left foot lands.

There is also a belief that an imbalance of electrolytes (such as calcium, potassium, and sodium) in the blood could also contribute to the side stitch.

Prevention

 * Drink water or fluids before hand. Dehydration is a common cause of side stitches.
 * Start off slow then gradually get faster as you jog/run
 * Improve fitness
 * Strengthen the diaphragm by using exercises such as those that aid respiratory rehabilitation
 * Strengthen core muscles (abdominals, lower back, obliques)
 * Limit consumption of food and drink, two to three hours before exercising (in particular, drinks of high carbohydrate content and osmolarity (reconstituted fruit juices))
 * Warm up properly
 * Gradually increase exercise intensity when running
 * Run on soft surfaces
 * Breathe with full exhalation
 * Slow the pace of the exercise.

Treatment
Pain induced by the stretching of the visceral ligaments is relieved by removing or minimizing the applied force, by slowing or stopping the exercise and lying down until the pain subsides.


 * Stretching may relieve the pain of a stitch.
 * Slow down your pace until pain lessens.
 * Massage or press on the area with pain. Bend forward to stretch the diaphragm and ease the pain.
 * Raise both hands above your head and inhale fully, expanding your abdominal and thoracic cavities, then exhale fully, tightening your core muscles to do so until pain subsides.

Additional sources

 * 1) Sports Medicine 32(6): 2002. 261-269. The human spleen during physiological stress, Stewart & McKenzie
 * 2) Clin Nucl Med. 2010 Oct;20(10):884-7. The effect of exercise on normal splenic volume measured with SPECT. Otto et al.
 * 3) J Appl Physiol 74: 1024-1026,1993; Spleen emptying and venous hematocrit in humans during exercise. Laub et al.