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.
What a Side Stitch Actually Is
A side stitch is the sharp, cramping pain that strikes under the ribs, most often on the right side, during running, swimming, or other rhythmic exercise. Its technical name is exercise-related transient abdominal pain, usually shortened to ETAP. They are common, temporary, and not a sign of anything serious in otherwise healthy people.
They show up most often in activities with repetitive up-and-down motion, which is why runners and swimmers report them so frequently, but anyone doing vigorous cardio can get one. Beginners get them more often than experienced exercisers, partly because their core muscles and breathing patterns are not yet conditioned for the demands of the activity.
Why It Happens: The Leading Explanations
Researchers have not settled on one definitive cause, but a few explanations have the most support. Understanding them helps because each one points to a different prevention strategy.
The friction theory
The most widely discussed explanation involves the layers of tissue lining the abdominal wall. During repetitive vertical movement, these layers can rub against each other, and the nerves supplying them may become irritated, producing that sharp localized pain.
Food, drink, and breathing patterns
Eating a large meal or drinking a lot of fluid, especially sugary or carbonated drinks, shortly before exercise is one of the most consistent triggers. A full stomach increases pressure in the abdominal cavity and adds to the mechanical bouncing. Shallow, rapid breathing also contributes: when you breathe quickly and shallowly, the diaphragm does not fully relax between breaths, which can lead to cramping sensations. Poor posture while running, such as slouching with the rib cage collapsed, may add to the problem by restricting the diaphragm’s movement.
How to Get Rid of a Stitch Mid-Workout
When one hits, slow down first. Dropping your pace or briefly stopping gives the irritated tissue a chance to settle. While you slow down, switch to deep, slow belly breaths instead of shallow chest breathing. Some runners find it helps to time their exhale with the foot strike on the opposite side of the stitch: if the pain is on the right, exhale as the left foot lands.
Pressing your fingers firmly into the sore spot while you breathe deeply can ease the cramp for many people. A gentle side stretch, raising your arm overhead and leaning away from the painful side, stretches the abdominal wall and may help. If the pain does not ease after a few minutes of these measures, stop and walk until it passes completely before resuming.
One important note: pain that is severe, does not fade with rest, or comes with symptoms like chest pain, dizziness, or difficulty breathing is not a normal side stitch. Treat those as reasons to stop and seek medical advice, not to keep running. This matches the Mayo Clinic’s general exercise guidance, which advises checking with a health professional when something feels wrong rather than pushing through it.
Preventing Stitches With Warm-Ups and a Stronger Core
The best treatment is not getting one in the first place. Start your sessions gradually rather than launching straight into hard effort: a proper warm-up before your workout raises blood flow, loosens the torso, and lets your breathing settle into a rhythm before intensity climbs. Avoid large meals for at least one to two hours before vigorous exercise, keep pre-workout snacks light, and stay reasonably hydrated without gulping large volumes right before you start.
Core conditioning helps over time. A stronger, more stable trunk bounces less internally during running, which reduces the mechanical irritation behind the stitch. You do not need endless crunches to get there: our guide on building core strength without endless crunches covers more effective approaches. Deep, diaphragmatic breathing practice also trains the breathing pattern that stitches seem to dislike.
Finally, fitness itself is protective. Stitches that plague your first month of running often fade on their own by month three. More beginner-friendly guidance on building that base is waiting at All Day Health & Fitness.
Frequently Asked Questions
Should I keep running with a side stitch?
Slow down first and try deep breathing, pressure on the spot, and a gentle stretch. If the pain eases, you can gradually resume. If it does not ease within a few minutes, stop and walk until it passes. Pushing through rarely works and usually makes it worse.
Why do I always get a stitch on my right side?
The right side is the most common location, and one theory is that it relates to the liver sitting under the right rib cage, adding weight and movement to that area during bouncing exercise. That said, stitches can occur on either side, and the side does not indicate anything wrong.
Does drinking water during exercise cause stitches?
Small, steady sips are fine and good for hydration. Gulping large volumes at once, especially right before or during intense running, can increase abdominal pressure and trigger a stitch. Sip steadily rather than drinking a lot at once.
Can breathing technique really prevent side stitches?
It can help. Deep, rhythmic belly breathing keeps the diaphragm moving fully instead of locking into shallow, rapid patterns. Many runners use a breath-to-stride rhythm, and deliberately exhaling on the foot strike opposite the stitch can ease one that has started.
When should I worry about abdominal pain during exercise?
A typical side stitch is sharp, localized under the ribs, and fades with rest. Pain that is severe, spreads, does not fade after stopping, or comes with chest pain, dizziness, nausea, or trouble breathing deserves prompt medical attention rather than self-treatment.
Conclusion
Side stitches are one of exercise’s most annoying small mysteries: common, painful in the moment, and almost always harmless. Slow down when one hits, breathe deeply, and give it a few minutes. Then work on prevention with gradual warm-ups, lighter pre-workout eating, steadier breathing, and a stronger core. Most of the time, better conditioning makes them disappear on their own.
