A stitch in medical terms is known as “exercise-related transient abdominal pain”. People often describe it as a sharp or stabbing pain, or sometimes cramping, aching or pulling in the side, just below the ribs. Some people can overcome the pain and continue to exercise, but most will need to slow down or stop for relief.
The pain will usually subside within a few minutes of stopping exercise, although some people may be sore for a few days afterwards if the initial pain was quite severe.
Why do we get a stitch?
We don’t know what causes a stitch. However, for a long time it was thought during high-intensity or lengthy exercise, there was a reduction in blood flow to the diaphragm, the large muscle involved in breathing, in favour of supplying blood and oxygen to the working limb muscles.
This idea is now not well regarded because both the leg muscles and the diaphragm work harder during running so it is unlikely blood would be shunted away from a muscle that is working hard. A study assessed the health of the diaphragm muscle of participants while they were and were not experiencing a stitch and found no difference. This suggests the amount of activity of the muscle was the same in both conditions therefore not likely to be the origin of the pain.
A stitch can occur during any kind of mid- to high-intensity exercise, however it is mostly associated with running. A current explanation is that during running, the stitch is caused by the weight of organs such as the stomach, spleen and liver pulling on ligaments that connect them to the diaphragm. Perhaps the jolting of the organs while running puts strain on these ligaments resulting in the stitch. But, since stitches can occur in other forms of exercise like cycling, rowing and swimming, perhaps this is not the answer either.
Some have suggested level of fitness is the key, however there are plenty of very fit runners who have a stitch during training.
The author of a literature review on exercise-related transient abdominal pain suggested during exercise the lining of the inside wall of the abdominal cavity, called the peritoneum, gets irritated which results in the stitch. This would depend largely on the type and amount of food eaten just before exercising.
How do you resolve and prevent a stitch?
A pre-run meal to boost energy stores is not necessarily a bad idea, but choosing the right type and amount of food and leaving enough time between eating and exercising are all important factors.
Prevention is better than cure and the idea that pre-exercise food intake may be the cause of the stitch is reasonable; so limit the amount of food you eat before your run.
Foods higher in fibre and fat take longer to digest so give yourself plenty of time for that process to run its course before you run yours. You should allow at least one and a half hours after eating before you begin exercising.
Don’t eat a large meal in the two hours prior to the exercise and in particular avoid sugary drinks like soft drinks and juice, and sugary foods like lollies. Since the most likely explanation for the stitch currently, is the irritation of the lining of the peritoneum, limiting your food and drink intake before running will be most important.
Ensuring you are well hydrated before beginning your training session will also help. This requires drinking lots of water in the 12 hours before exercise. Then in the two hours before, just drink small amounts to make sure you do not bloat or need to go to the toilet during training, or worse, a race or match.
Going from relaxed, straight into a fairly high intensity run may also result in a severe stitch in a matter of minutes. So, begin with a warm up and build the intensity gradually. This will optimise your workout and reduce the chance of a stitch.
If you breathe regularly and efficiently you can synchronise the breathing rate with your strides. So breathe in for two or three strides and out for two or three strides. If your stride rate changes, your breathing rate should change with it.
If a stitch does occur, usually it will ease if you stop or reduce the intensity of the activity. So, be careful about what you eat prior to exercise and, if you do get a stitch, take a short break before resuming exercise.
Andrew Lavender does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.
Authors: Andrew Lavender, Lecturer, School of Physiotherapy and Exercise Science, Curtin University