What Causes a Side Stitch During Exercise
A side stitch during exercise is that sharp, cramp-like pain under your ribs, usually on the right side, that shows up during running, swimming, or other rhythmic cardio. The most consistent explanation is irritation of the ligaments and diaphragm that support your organs, made worse by a full stomach, shallow breathing, or a sudden increase in pace.
What causes a side stitch during exercise
The ligaments that anchor your liver, stomach, and other organs to your diaphragm get pulled with each stride, especially as your torso moves up and down. Add a stomach that’s still digesting food, breathing that’s too shallow to fully expand the diaphragm, or a pace that ramped up faster than your body adjusted to, and that repetitive pulling can turn into the sharp jab under the ribs most people know as a stitch.
What tends to bring it on
- Eating or drinking a large amount shortly before exercising
- Shallow, chest-only breathing instead of breathing into the belly
- Starting a run or swim faster than your warm-up pace
- Poor posture that compresses the torso, like running hunched forward
Easing it mid-session
Slowing your pace and taking slower, deeper breaths is usually the fastest way through it. Some people find pressing a hand into the affected side or exhaling forcefully when the opposite foot strikes the ground helps break the pattern. If it doesn’t ease within a few minutes, walking until it passes is a reasonable choice — pushing through sharp pain to protect a pace target isn’t worth it.
Making it less likely next time
Leaving more time between eating and exercising, warming up gradually rather than starting at race pace, and practicing deeper breathing during easier sessions all seem to reduce how often stitches show up. None of this is guaranteed — some people are simply more prone to stitches than others, and that’s not a sign of poor fitness.
Younger and less experienced runners tend to report stitches more often, and they tend to fade somewhat as the body adapts to a consistent training routine. That doesn’t mean an experienced athlete is immune — a new activity, a faster-than-usual pace, or exercising soon after a bigger meal than normal can bring one on regardless of fitness level.
A stitch is uncomfortable but not dangerous in the way that chest pain, pressure, or pain radiating down an arm would be. Those symptoms are different and warrant stopping and seeking medical attention rather than working through them. If sharp abdominal pain during exercise is frequent, severe, or lingers well after you stop, it’s worth mentioning to a doctor rather than assuming it’s just a stitch.
The NHS’s running tips for beginners cover pacing and breathing habits that also tend to lower stitch frequency. Muscle discomfort during and after exercise isn’t always a problem to solve — the same is true of DOMS, which is uncomfortable but expected rather than a sign something is wrong.
Most stitches resolve on their own within a session and don’t point to anything serious.
