Not much is known about why you get a stitch, but scientists agree that the stitch can be described as an area of pain just below the ribs, which can hit both right and left sides of the body. It is a pain that occurs and disappears suddenly.
There are several theories as to why you get stitch.
One theory is that it’s due to fatigue in the diaphragm. The diaphragm is an important respiratory muscle, which is used for breathing and stabilizing the breath. When the abdominal muscles are tightened, it can cause fatigue and in turn, a stitch.
Another theory is that a full stomach could be the cause, because the lamina surrounding the stomach can become irritated.
Recent scientific studies made by, among others, Darren P. Morton (from Avondale centre of exercise in New South Wales, Australia) show that if you run, you get a stitch more frequently than if you are doing other physical activities. This is especially the case when running downhill. Cyclists, for example. rarely get a stitch, and perhaps that is because when you run, the organs pulls in the diaphragm due to the tremors that occur when running. Cyclists do not experience the same shaking and twisting of the organs.
Darren P. Morton’s studies also showed that if you have a tendency to curving of the spine, there is a greater probability of getting a stitch.
If you consume carbohydrates in the form of fluids before and during exercise, it increases the risk of getting a stitch – possibly because fluids with a high content of carbohydrates pass more slowly through the system.