Why Do Runners Get Side Stitches? (And How to Stop Them)

We’ve all been there: cruising through a run when suddenly a sharp pain hits just below your ribs. The dreaded side stitch. It’s one of the most common — and frustrating — problems runners face.

But side stitches don’t just appear randomly. They’re usually triggered by a few specific factors, including breathing patterns, posture, and even what you ate before your run.

The good news? Once you understand what causes them, there are simple ways to reduce your chances of getting one. Here’s what’s actually going on — and how to stop a side stitch when it strikes.

What Is a Stitch, Exactly?

A stitch — technically called exercise-related transient abdominal pain (ETAP) — is a cramp or sharp pain usually felt on the side of the abdomen, just under the rib cage. It can come on quickly, often early in a run or during higher-intensity efforts, and can range from mild discomfort to a stabbing pain that forces you to slow down or stop.

What Causes a Stitch While Running?

Despite how common they are, what exactly causes a side stitch while running isn’t 100% settled. But there are several leading theories:

1. Diaphragm irritation or cramping

Your diaphragm — the muscle that helps you breathe — may spasm or cramp from shallow or irregular breathing, especially during hard efforts or after eating.

2. Ligament strain

Some research suggests that the ligaments connecting your internal organs to your diaphragm get tugged during running (especially when there’s food in your stomach), causing pain.

3. Poor core stability

Weak or underused core muscles can contribute to poor posture and excessive movement in the torso, which may increase the likelihood of a stitch.

4. Eating or drinking too close to your run

A full stomach — especially one filled with high-fat or high-sugar foods — can increase pressure on your diaphragm and digestive system, triggering discomfort.

One study even found that sugary drinks made stitch pain worse — so stick to water or well-balanced sports drinks, especially before and during harder efforts.

How to Stop a Stitch Mid-Run

If a stitch hits, try these strategies to relieve it:

• Slow down your pace. Ease off until the pain subsides.
• Change your breathing. Take deep belly breaths to relax your diaphragm. Try exhaling forcefully as your foot on the opposite side of the stitch hits the ground.
• Apply pressure. Gently press into the painful area with your fingers as you exhale.
• Stretch it out. Raise your arms overhead and lean away from the side where it hurts.

For most runners, the stitch fades after a few minutes — but prevention is where the real power lies.

How to Prevent Side Stitches

These tips can help you avoid stitches altogether:

1. Watch your pre-run nutrition

Avoid eating large meals within 2–3 hours of running. Steer clear of greasy, sugary, or very fibrous foods pre-run.

👉 If you’re planning a long race, check out this guide to what to eat during an ultramarathon

2. Warm up properly

Start your run with a gradual warm-up to ease your body into movement and regulate your breathing.

3. Focus on your breathing

Shallow chest breathing (or holding your breath when you’re pushing hard) can make stitches worse. Instead, focus on deep belly breathing — also called diaphragmatic breathing — to engage your core and reduce cramping.

4. Strengthen your core

Add planks, bridges, and rotational core exercises to your weekly routine. A stronger core can reduce jostling and improve posture on the run.

5. Practice pacing

Going out too hard increases the likelihood of a stitch. Build gradually into your runs, especially if you’re doing speed work.

👉 Pacing too aggressively is also a common marathon mistake — here are a few others to avoid

Final Thoughts

Side stitches are annoying — but they’re not a sign of anything serious. With a few tweaks to your fuelling, breathing, and form, most runners can keep them at bay.

Next time a stitch hits, don’t panic. Slow down, breathe deep, and remember: it’ll pass.