A side stitch is a sharp, stabbing pain just below your ribs that hits during physical activity. It’s harmless, and you can usually make it stop within seconds by changing your breathing pattern, pressing into the painful spot, or stretching. If you keep getting stitches, a few simple habits before and during exercise can prevent them from coming back.
What Causes a Stitch
The exact cause is still debated, but the leading theory points to irritation of the parietal peritoneum, a thin membrane that lines the inside of your abdominal cavity. When this membrane gets jostled or stressed during repetitive motion, the nerves running through it fire pain signals to the sides of your torso. That’s why the pain almost always shows up in the left or right flank, right where the intercostal nerves that serve this lining pass between your ribs.
Other contributing factors include cramping of the abdominal muscles themselves, reduced blood flow to the diaphragm, and tugging on the ligaments that connect your organs to the underside of the diaphragm. Running and other high-impact activities are the most common triggers because of the constant up-and-down jarring, but swimming, cycling, and even horseback riding can bring one on. Eating or drinking too much beforehand makes it worse because a full stomach adds weight and friction against that sensitive lining.
How to Stop a Stitch Mid-Exercise
You don’t necessarily need to stop moving entirely. Try these techniques in order, starting with the one most people find effective first.
Switch to deep belly breathing. Most people breathe shallowly when exercising hard, which keeps the diaphragm tense. Inhale slowly and deeply through your nose, letting your belly push outward rather than your chest rising. Then exhale slowly through pursed lips. This relaxes the diaphragm and reduces the pulling on surrounding tissues. Three or four full breath cycles like this often resolve a mild stitch without breaking stride.
Press into the painful area. Use two or three fingers to push firmly but gently into the spot where the pain is sharpest. While pressing, lean your torso forward slightly. The combination of direct pressure and bending forward seems to relieve tension on the peritoneal lining. Hold for 10 to 15 seconds.
Stretch away from the pain. Raise the arm on the same side as your stitch above your head. Then bend your torso gently in the opposite direction, keeping that arm extended. This lengthens the muscles and tissues along the painful side. Hold the stretch for 15 to 30 seconds while continuing to breathe deeply.
Slow down or walk. If breathing and stretching aren’t enough, reduce your pace to a walk. The stitch will typically fade within a minute or two once the repetitive impact lessens. You can pick up speed again once the pain is completely gone.
Why Your Breathing Pattern Matters
Shallow, rapid chest breathing is one of the biggest contributors to stitches. When you breathe only into the top of your lungs, your diaphragm stays partially contracted and never fully relaxes between breaths. Over time during a run, this creates a kind of sustained cramp in the diaphragm and increases friction against the tissues attached to it.
Diaphragmatic breathing, where you consciously direct air into the lower lungs by expanding your belly, gives the diaphragm a full range of motion. Practicing this at rest makes it easier to default to it during exercise. A simple drill: lie on your back with one hand on your chest and one on your stomach. Breathe so that only the stomach hand rises. Once this feels natural lying down, practice while walking, then while jogging.
How to Prevent Stitches Before They Start
Prevention is more reliable than any mid-run fix. Most stitches trace back to what you ate or drank, how you warmed up, or how fit your core is.
Time Your Meals
A full stomach is the single most controllable risk factor. Allow at least two hours between a large meal and intense exercise. If you need a small snack closer to your workout, keep it low in fat and fiber, since both slow digestion and leave more volume sitting in your stomach. A banana or a piece of toast 30 to 45 minutes before a run is generally fine; a bowl of pasta is not.
Choose the Right Drinks
High-sugar, high-concentration beverages are strongly linked to stitch frequency. Drinks that are hypertonic (more concentrated than your blood) seem to disrupt the fluid balance inside the abdominal cavity, aggravating the peritoneal lining. Fruit juice, full-sugar sports drinks, and sodas are common culprits. Stick to water or a hypotonic sports drink (one with a lower sugar concentration) in the hour before and during exercise.
Warm Up Gradually
Jumping straight into a hard pace forces your diaphragm and abdominal muscles to work at full capacity before they’ve had a chance to loosen up. Start with five minutes of easy jogging or brisk walking. This gives your breathing rhythm time to settle and your core muscles time to engage properly.
Strengthen Your Core
Research has explored whether activating the deep abdominal muscles, particularly the transversus abdominis (the deepest layer of your core), can reduce stitch occurrence. A stronger core provides better support for the organs and tissues inside your abdomen, reducing the jostling that irritates the peritoneal lining. Planks, dead bugs, and Pilates-style exercises that emphasize deep core activation are good options.
When Pain Isn’t Just a Stitch
A true side stitch is localized, predictable, and fades quickly once you slow down or stop. Certain symptoms during exercise signal something more serious. Chest pressure or pain on the left side of your body, pain that radiates to your neck, jaw, shoulder, or arm, nausea combined with sweating, or shortness of breath that seems out of proportion to your effort level can indicate a cardiac problem. These warrant stopping immediately. If the pain doesn’t go away within a few minutes of rest, or if it comes with any of those additional symptoms, seek emergency medical help.
Persistent abdominal pain that shows up whether or not you’re exercising, or pain that gets worse over days rather than resolving in minutes, is also not a stitch. Conditions involving the liver, spleen, or intestines can mimic the location of a stitch but behave very differently over time.