This is Part 2 in our series on common running issues that don’t get enough attention, the uncomfortable stuff runners deal with but rarely discuss. These aren’t injuries that’ll sideline you for months, but they’re annoying enough to ruin runs and make you question what you’re doing wrong. Read Part 1: Why Do I Keep Getting UTIs after Long Runs?
You’re five kilometers into your run and that familiar sharp pain starts on your right side. You slow down, press your hand into your ribs, try to breathe differently. Sometimes it goes away. Sometimes you have to stop completely. A stitch when running isn’t dangerous, but it’s annoying as hell when you’re trying to hit pace or finish a long run. Here’s what’s actually happening and what works to prevent it.
What’s Actually Happening
A side stitch is sharp pain in your abdomen while running, usually on the right side just below your ribs. The medical term is exercise-related transient abdominal pain.
Nobody knows exactly what causes it. The leading theory: your diaphragm muscle gets irritated. Your diaphragm sits under your ribs and controls breathing. When you run, your organs bounce and pull on the ligaments connected to it. Add shallow breathing from pushing pace, and you get that stabbing pain.
You get them more on the right because your liver sits there and weighs more than the organs on your left side.
When It’s Not Just a Stitch
Most of the time, if the pain goes away when you stop running, it’s a stitch. But sometimes what feels like a side stitch is actually something else.
See a doctor if:
- Pain doesn’t go away after you stop running
- You have pain when you’re not exercising
- The pain is severe or gets worse over time
- You have other symptoms like nausea, vomiting, or fever
- The pain is in your lower right abdomen (could be appendicitis)
If you’re worried it might be something serious, get it checked out. You won’t regret catching something early.
Why It Keeps Happening
I’ve worked with runners who dealt with chronic stitches for months. Here’s what usually causes them:
- Eating too close to running. Your stomach needs blood to digest. Your muscles need blood to run. Ask your body to do both and your diaphragm doesn’t get enough oxygen. Most runners need 2-3 hours after a meal before running hard. Light snacks might only need 30-60 minutes, but it depends.
- Breathing wrong. Shallow chest breathing doesn’t fully engage your diaphragm. When you only use the top part of your lungs, your diaphragm stays tight and cramped instead of moving through its full range.
- Going out too fast. If you start a run at a pace your aerobic system can’t support yet, you’ll default to shallow breathing. Your body panics for oxygen and your diaphragm locks up.
- Weak core. Your core stabilizes your torso while you run. If it’s weak, you compensate by tensing your diaphragm and intercostal muscles (the ones between your ribs). Run like that for 30 minutes and something’s going to cramp.
- Hydration issues. Both dehydration and drinking too much water right before running can trigger stitches. Dehydration affects how well your muscles function. Overhydration sloshes around in your stomach and pulls on those diaphragm ligaments.
What Actually Works
These are strategies I use with clients who kept getting stitches on long runs or tempo workouts.
Dial in your pre-run timing. Track what you eat and when, then note if you get a stitch during that run. Most people find their window after a few weeks of paying attention. Mine is 2.5 hours after a normal meal, 90 minutes after something light like a banana.
Learn to breathe with your belly. Put one hand on your chest and one on your stomach. When you breathe in, your stomach hand should move more than your chest hand. This engages your diaphragm fully instead of just using your upper chest.
Practice this lying down first, then sitting, then standing, then while walking. Eventually you can do it while running, but it takes time to override years of chest breathing.
Warm up properly. Start every run slow enough that you can hold a conversation. Your breathing should feel easy for at least the first 10 minutes. This gives your aerobic system time to kick in before you ask it to work hard.
Strengthen your core. Planks, dead bugs, bird dogs, pallof presses. You don’t need an elaborate routine. Two or three core exercises, three times a week, done consistently for a few months will make a difference.
The goal isn’t visible abs. The goal is a core that can stabilize your torso without your diaphragm having to help.
Stay hydrated throughout the day, not right before. Drink water consistently in the hours leading up to your run. Stop drinking 30-60 minutes before you start. If you’re thirsty right before a run, take small sips instead of chugging a full glass.
If You Get a Stitch Mid-Run
When a stitch hits in the middle of a run, here’s what actually helps:
- Slow down or walk. Pushing through it doesn’t make it go away faster. Drop your pace until you can breathe comfortably again.
- Press into the pain. Use your fingers to push into the spot where it hurts while you take slow, deep breaths. This can help release the cramped muscle.
- Breathe out when your opposite foot hits the ground. If the stitch is on your right side, exhale when your left foot strikes. This changes the pressure pattern on your diaphragm.
- Raise the arm on the painful side. Lift your right arm straight up over your head if the pain is on your right side. This stretches the area and can help release the cramp. You’ll look weird but it works.
- Bend forward at the waist. Stop running and lean forward with your hands on your knees. Take slow, deep belly breaths. This stretches your diaphragm and can stop the spasm.
Most stitches go away within a few minutes if you back off the intensity and focus on breathing. Once it’s gone, you can gradually build back up to your target pace.
FAQ
Usually the right side because your liver is heavier than anything on the left. Extra weight means more pull on the diaphragm. Some people get them on the left. Some get both.
Mostly yes. Better fitness helps. Better pacing helps more. Core strength and breathing technique make a difference. New runners get them constantly. Experienced runners get them occasionally.
Not really. They happen at all fitness levels. More common when you’re new or pushing harder than your fitness supports. But even fast runners get them if they screw up their pre-run meal.
No. Static stretching before running doesn’t do anything for stitches. A real warm-up (starting slow) works better. Core work done consistently over weeks helps more than any pre-run routine.
Nothing reliable. The evidence is weak for anything you can take. Better strategies: timing your food, breathing properly, building core strength.
Yes. More impact, more organ bounce, more diaphragm pull. Long downhill sections trigger stitches even at easy pace if you’re prone to them.
Usually the right side because your liver is heavier than anything on the left. Extra weight means more pull on the diaphragm. Some people get them on the left. Some get both.
Mostly yes. Better fitness helps. Better pacing helps more. Core strength and breathing technique make a difference. New runners get them constantly. Experienced runners get them occasionally.
Not really. They happen at all fitness levels. More common when you’re new or pushing harder than your fitness supports. But even fast runners get them if they screw up their pre-run meal.
No. Static stretching before running doesn’t do anything for stitches. A real warm-up (starting slow) works better. Core work done consistently over weeks helps more than any pre-run routine.
Nothing reliable. The evidence is weak for anything you can take. Better strategies: timing your food, breathing properly, building core strength.
Yes. More impact, more organ bounce, more diaphragm pull. Long downhill sections trigger stitches even at easy pace if you’re prone to them.
Bottom Line
A stitch when running means something isn’t working right. Usually you ate too soon, started too fast, or you’re breathing shallow. Sometimes it’s weak core. The fix isn’t complicated, but you have to pay attention and be willing to slow down.
Track when you eat before runs. Work on breathing with your belly. Don’t skip warm-ups. Do some core work. If the pain doesn’t stop when you stop running, or it happens when you’re not exercising, see a doctor. Otherwise it’s just your body telling you to adjust something.
If you need help building a training plan that prevents these issues, check out Flex, our running and endurance coaching program, or book a free discovery call to talk through your training.
