Why does my lower right abdomen hurt when I run?

If you've ever felt a sharp, stabbing pain in your lower right abdomen while running, you're not alone. This is a very common experience among runners of all levels. The good news is that it's usually not a serious medical issue but rather a temporary discomfort known in sports medicine as Exercise-Related Transient Abdominal Pain (ETAP)—or more commonly, a “side stitch.”

Let's take a closer look at why this happens, what you can do about it in the moment, and how to prevent it in the future.

What Causes This Pain?

Several factors can contribute to pain in the lower right abdomen during running. Here are the most common explanations:

The diaphragm is the muscle that separates your chest and abdomen and plays a key role in breathing. When you run, your breathing becomes faster and shallower to meet increased oxygen demands. This can cause the diaphragm to contract more frequently, become fatigued, and even spasm.
Why the right side? Your liver is located in the upper right abdomen. It’s relatively large and heavy. The up-and-down motion of running can jostle the liver, pulling on ligaments connected to the diaphragm—most notably the falciform ligament. This added stress makes right-side diaphragm spasms more common.

Shallow, rapid chest breathing prevents the diaphragm from fully descending. This reduces oxygen exchange in the lungs and can lead to diaphragm fatigue and spasm.

After a meal, blood flow increases to your digestive system to aid digestion. If you start running too soon, blood is diverted to your leg muscles, leaving your intestines oxygen-deprived. This can cause cramping, gas pain, or general discomfort. The bouncing motion during running can also pull on stomach tissues.

Jumping straight into intense physical activity doesn’t give your respiratory muscles and internal organs enough time to adjust. A sudden workload can lead to dysfunction and pain.

Your core muscles act as a natural corset, stabilizing your trunk and supporting your internal organs. If these muscles are weak, there’s excessive movement of organs during running, which may irritate tissues and cause pain.

Sweating during running leads to fluid and electrolyte loss. This can make muscles—including the diaphragm and intestinal muscles—more prone to cramping.

How to Relieve the Pain Quickly

If you get a side stitch while running, try these methods:

• Slow down or stop: Reduce your pace or walk until the pain subsides.

• Adjust your breathing:

  • Practice deep belly breathing: Inhale slowly and deeply through your nose, letting your abdomen expand. Exhale fully through your mouth.

  • Use a rhythmic breathing pattern such as inhaling for three steps and exhaling for two.

• Press on the painful area: Gently press your fingers into the spot that hurts and lean forward slightly.

• Stretch: Raise your right arm overhead and bend gently toward your left side. This stretches the right torso and may help relax the diaphragm.

How to Prevent It

Prevention is always better than cure. Incorporate these habits into your routine:

• Time your meals: Avoid large meals 1.5–2 hours before running. If you need a snack, have something light like a banana about an hour beforehand. Stay away from high-sugar or gas-producing foods (e.g., beans, carbonated drinks).

• Warm up properly: Spend 5–10 minutes doing dynamic stretches or light cardio (e.g., walking, high knees, jumping jacks) to prepare your body.

• Practice diaphragmatic breathing: Train yourself to breathe deeply and rhythmically both at rest and during runs.

• Build intensity gradually: Avoid sudden increases in running distance, speed, or intensity.

• Strengthen your core: Include planks, bridges, and abdominal exercises in your regular workout routine.

• Stay hydrated: Drink water throughout the day and consider an electrolyte-replenishing drink during longer runs.

When Should You See a Doctor?

While side stitches are usually harmless, you should consult a healthcare professional if you experience any of the following:

• Severe or persistent pain that doesn’t improve with rest

• Dull, constant ache rather than a sharp cramp

• Fever, nausea, vomiting, diarrhea, or blood in stool

• Pain that is tender to the touch or occurs even at rest

These could be signs of more serious conditions such as appendicitis, a hernia, ovarian issues (e.g., cysts or torsion), or kidney stones. A proper medical evaluation is essential in such cases.

Stay safe and listen to your body. Happy running!