What is the stitch?

Athlete with a stitch
Author:  Michelle Minehan, Dietitian, Sports Nutrition, Australian Institute of Sport
Issue: Volume 3 Number 2

Stitch is a localised pain usually felt on the side, just below the ribs.  It is sometimes accompanied by a stabbing pain in the shoulder joint.  The pain can range from sharp or stabbing to mild cramping, aching or pulling.  Sometimes people can exercise through the pain however, but usually the sufferer is forced to slow down or cease exercise. 

The pain usually eases within a few minutes after exercise has stopped, however some people experience some residual soreness for a few days, especially after severe pain.  Stitch seems to be more prevalent in activities that involve vigorous upright, repetitive movement of the torso.  Activities such as running (particularly when going down hill) and horse riding may be more prone to causing stitch however it can occur in any type of activity.

What causes stitch?

Scientists are unsure of the exact cause of stitch.  For some time, stitch was thought to be caused by a reduction in blood supply to the diaphragm, a large muscle involved in breathing.  It was thought that during exercise, blood was shunted away from the diaphragm and redirected to exercising muscles in the limbs.  This theory has now lost favour with scientists.  Both the diaphragm and the limb muscles have to work harder during exercise so it is unlikely that an inadequate blood flow would be directed to them.

Another popular theory is that stitch is caused by organs pulling on the ligaments that connect the gut to the diaphragm.  Ligaments that support organs such as the stomach, spleen and liver are also attached to the diaphragm.  Jolting during exercise may cause these organs to pull on the ligaments and create stress on the diaphragm.

A more recent idea is that stitch is caused by irritation of the parietal peritoneum.   Two layers of membrane (peritoneum) line the inside wall of the abdominal cavity.  One layer covers the abdominal organs.  The other layer (parietal peritoneum) attaches to the abdominal wall.  The two layers are separated by lubricating fluid, which allows the two surfaces to move against each other without pain. 

The parietal peritoneum is attached to a number of nerves.  It is thought that the stitch occurs when there is friction between the abdominal contents and the parietal peritoneum.  This friction may be caused by a distended (full) stomach or a reduction in the lubricating fluid.

Eating and drinking inappropriately prior to exercise may exacerbate stitch by causing a full stomach or dehydration.  Poor fitness, an inadequate warm-up and exercising at high intensity may also be factors.  A sudden change in biomechanics such as increased stride length or frequency may increase the risk of stitch by affecting the way that the torso moves.

How can I avoid stitch?

Eating just before exercise or consuming inappropriate foods and fluids seem to exacerbate the stitch.  High-fat foods, and foods and fluids with a high sugar concentration are more likely to cause problems.  The likelihood of stitch occurring may be reduced by allowing two to four hours before exercising after a large meal and choosing high-carbohydrate, low-fat and moderate to low-protein options in the pre-exercise meal. 

During exercise, it is possible that a full stomach contributes to stitch.  Concentrated fluids such as soft drink and cordial empty slowly from the stomach, therefore are likely to lead to a fuller stomach.  Water and sports drink empty more quickly and are a better option.  It is also preferable to adopt a pattern of consuming small amounts of fluid at frequent intervals during exercise rather then trying to drink large volumes all at once.
 
Stitch may also be minimised by following a training schedule that progressively increases in intensity and duration.  Sudden increases in intensity are more likely to cause stitch.  It is much better to start at an easy level and slowly build up.

How should stitch be treated?

Sometimes the stitch eases if you slow down and drop your intensity for a period.  However, the most common way to alleviate stitch is to bend forward while pushing on the affected area and breathing deeply.  Sometimes this can be done while exercising, but usually the pain eases more quickly when exercise stops.  Another option is to lie down while elevating the hips.

Does stitch indicate a more serious problem?

The stitch is rarely a sign of more serious problems.  However any pain that is persistent and does not ease when exercise ceases should be investigated by a doctor.

For more information or this or related topics, visit the AIS Nutrition website.


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