Why Do I Get a Side Stitch When Running? | Beat Stitch Pain

Running can feel smooth, loose, and rhythmic right up to the second a side stitch cuts in. Then the whole run changes. Your breath gets choppy. Your body folds a little. You press your fingers into your side and start bargaining with the next lamppost.

That pain is common, and it has a medical name: exercise-related transient abdominal pain. Most runners know it as a side stitch. It often shows up under the ribs, more often on the right, and it can feel like a cramp, a tug, or a sharp jab that lands with each step.

The reason it happens is not one clean, settled answer. A side stitch seems to show up when a few things line up at once: hard breathing, repeated torso motion, food or fluid sitting badly, and a body that went from calm to hard effort too fast. Once you start treating it like a pattern instead of bad luck, it gets easier to tame.

What a side stitch usually feels like

A side stitch does not feel like general stomach upset. It tends to stay in one spot. Many runners feel it along the lower edge of the rib cage or the mid-abdomen. Mild pain can feel like a nagging pull. Stronger pain can feel sharp enough to wreck your rhythm in a few strides.

The pain also has a habit of changing with effort. Jog easy and it may settle into a dull ache. Surge up a hill or try to hold race pace and it can turn into a stabbing pain that makes full breaths feel hard.

• It often sits in one small area instead of spreading across the whole belly.
• It may flare with each inhale or each foot strike.
• It often eases when you slow down, bend forward a bit, or stop.
• Some runners also feel an odd ache near the shoulder tip at the same time.

That last one throws people off, yet it can happen with a stitch. So if your side pain and a brief shoulder-tip ache show up together during a hard run, that pairing is not unheard of.

Side stitch when running: What tends to set it off

No single trigger explains every stitch. Still, a few patterns show up again and again. One AMSSM side stitch fact sheet notes that the pain is common in sports with repeated jarring, shaking, or twisting, and that many athletes report it after eating or drinking.

Breathing load and torso motion

A hard start can light the fuse. When you jump from standing still to a fast pace, your breathing rate spikes, your upper body gets tense, and each landing sends more force through the ribs and abdomen. Running is full of repeated motion, so even a small mechanical problem can keep getting tapped over and over.

Shallow breathing can make that worse. If your chest lifts while your rib cage stays stiff, your breathing can feel rushed and clipped. A side stitch is not just a “bad lungs” problem, though. Fit runners get them too. The difference is that they often learn their own warning signs sooner.

Meals and drinks too close to the run

Food timing is one of the biggest clues. A large meal, a sweet drink, or a lot of fluid right before a run can leave your gut feeling heavy and unsettled. MedlinePlus nutrition and athletic performance notes that pre-workout food timing and amount vary by person, and it also advises limiting fat in the hour before an athletic event.

That does not mean you should bolt out the door on an empty stomach every time. Plenty of runners feel flat when they do that. The sweet spot is often a small, familiar snack with enough time to settle, then a calm start instead of an all-out first mile.

Posture, pacing, and trunk fatigue

Side stitches also show up more often when form gets sloppy. A slumped posture can make breathing feel cramped. Tight shoulders can pull tension upward. Overstriding can add more jolt to each landing. Then tired trunk muscles stop helping you stay tall and steady, so the whole system feels rougher.

That is why some runners only get stitches late in a run. Their early form is fine. Then fatigue creeps in, the rib cage stiffens, the stride gets louder, and the pain shows up.

What to do when the pain starts

You usually do not need a grand fix in the moment. You need a reset. Most stitches calm down once you lower the strain that set them off.

1. Back off the pace. Slow to an easy jog or a walk for a minute.
2. Press the sore spot. Firm pressure can dull the jab enough to break the cycle.
3. Exhale fully. Blow the air out on purpose, then take a calmer breath in.
4. Bend slightly forward. Many runners find this takes the edge off.
5. Relax your shoulders and jaw. Tension up top often travels down into the rest of your stride.

If the pain fades, do not jump straight back to race effort. Give it a few minutes at a calmer pace. Most runners who rush right back into the red just bring the pain with them.

Common setup	Why it may spark a stitch	Better move
Fast start with no easing in	Breathing load and torso tension climb too fast	Use 10 to 15 easy minutes before harder running
Big meal close to the run	Full stomach can feel heavy and unsettled	Leave a wider gap before hard sessions
Sweet drink or large fluid intake	Extra volume can slosh and feel rough	Take smaller sips and test what sits well
Shallow chest breathing	Rib cage stays tight under effort	Practice slower, fuller breaths on easy runs
Slumped posture	Breathing feels cramped and stride gets choppy	Run tall with loose shoulders
Overstriding	Each landing adds more jolt through the trunk	Shorten the stride and lift cadence a touch
Tired abdomen and back muscles	Less control over torso motion late in the run	Add steady trunk work two or three days a week
Unfamiliar race fuel	Gut and pace both get stressed at once	Practice race fueling on training runs

Habits that lower the odds on your next run

The best stitch fix is often boring. It lives in your routine. A few low-drama habits can cut the odds of the pain showing up at all.

Warm into pace

Most side stitches love a rushed start. Easy minutes at the front end give your breathing and stride time to settle. This matters even more before intervals, hills, or races.

Match breathing to effort

On easy runs, try fuller belly breathing instead of quick chest breaths. You do not need a rigid pattern. You just want smoother air flow and less panic. If your breath starts getting ragged, your body is often telling you the pace is ahead of your form.

Get your food timing straight

Stick with foods you already know sit well. Keep pre-run meals plain on hard days. If you use a snack, keep it light and give it time. On longer runs, practice drinking in small amounts instead of dumping a bottle down at once.

Train posture when you are fresh

Good form is easier to hold if you practice it before fatigue rolls in. A tall chest, loose arms, and a compact stride can make the whole run feel smoother. Then add simple trunk work on non-hard days: planks, dead bugs, bird dogs, and side planks all help you stay steadier when the pace climbs.

If this is your run	Try this next time	What to watch
Easy 30-minute jog	Run easy from the first minute and breathe through the belly	Whether the pain waits until pace picks up
Tempo or interval day	Add a longer warm-up and skip the heavy snack	Whether the stitch starts during the first hard rep
Long run	Practice small sips and steady fueling	Whether one drink or gel keeps setting it off
Race morning	Use only foods and drinks you already know	Whether nerves push you to start too hard
Late-run stitch every time	Add trunk work and shorten stride when tired	Whether posture breaks down before the pain hits

When it may be more than a stitch

Most side stitches are harmless and short-lived. Still, not every pain during a run should be brushed off. If the pain is sudden and sharp, sticks around long after you stop, or shows up when you are not running, it deserves a closer check.

MedlinePlus abdominal pain advises getting medical help right away for belly pain that is sudden and sharp, comes with chest, neck, or shoulder pain, or comes with a stiff and tender abdomen. Trouble breathing, vomiting blood, blood in the stool, or pain that does not settle are also not “just a stitch” signs.

• Pain that keeps coming back in the same spot no matter how easy the run is
• Pain that lasts for hours after the run ends
• Fever, vomiting, faintness, or chest pain with the side pain
• Pain that feels deeper, wider, or nothing like your old side stitch pattern

If any of that sounds familiar, get checked by a clinician instead of trying to run through it.

A side stitch is annoying, but it is often manageable once you spot your own pattern. Start a touch slower. Breathe deeper. Clean up meal timing. Stay tall late in the run. Those small fixes can turn a pain that used to hijack your miles into a brief blip that barely gets a say.