Experts don’t know exactly what causes those sharp, fleeting pains called side stitches, but many believe they’re due to diaphragm spasms triggered by rapid breathing, says Tom Holland, exercise physiologist and author of Beat the Gym. Eating too close to your workout may play a role. And side stitches occur more frequently in novice exercisers.
What to try: To stop a stitch, slow your pace and take deep breaths while contracting your abdominal muscles. Stretch your arms overhead or to the side. To prevent a stitch: Eat light pre-exercise meals, and wait at least 30 minutes after eating before you work out. Always warm up for five to ten minutes; gradually increase workout intensity.