Lower Rib Cage Stitch After Running: Diaphragmatic Ischemia vs. Intercostal Muscle Cramp

If the bottom of your ribs aches when breathing deeply after a run, the most likely explanation is a common exercise-related stitch rather than a dangerous loss of blood flow to the diaphragm. Still, the location of the pain can be confusing because several muscles and organs sit beneath the lower ribs.

A “stitch” is often called exercise-related transient abdominal pain (ETAP). It usually causes a sharp, cramping, or aching feeling along one side of the abdomen or under the ribs during or shortly after exercise. It can affect both trained and untrained runners.

Is it diaphragmatic ischemia?

Diaphragmatic ischemia means that the diaphragm is not receiving enough blood and oxygen. This is not the usual explanation for a typical running stitch. The diaphragm is the main breathing muscle, but it is supplied by several blood vessels and generally tolerates exercise well.

A more important concern is heart-related ischemia, in which the heart muscle does not receive enough oxygen. Heart pain can sometimes be felt in the upper abdomen, lower chest, back, shoulder, arm, or jaw rather than directly over the heart. However, this is much less common in a healthy younger runner, especially when the discomfort is brief, clearly linked to exertion, and resolves with rest.

A typical stitch is more likely when the pain:

• Begins during running or shortly afterward
• Is located under the ribs or along the side of the abdomen
• Improves when you slow down, stop, or change your breathing
• Does not spread to the arm, jaw, shoulder, or back
• Is not accompanied by fainting, severe breathlessness, cold sweating, or nausea

The cause of ETAP is not completely settled. Research has considered irritation of the lining around the abdominal organs, strain on supporting tissues, movement of the internal organs, and changes in breathing mechanics. It is not accurate to assume that every stitch is caused by the diaphragm becoming starved of oxygen.

Could it be an intercostal muscle cramp?

The intercostal muscles are small muscles between the ribs. They help expand and contract the chest during breathing. Running increases breathing rate and depth, so these muscles work harder than usual. A sudden increase in training, poor warm-up, dehydration, fatigue, or an awkward twist can contribute to a muscle spasm or strain.

An intercostal cramp or strain may feel like:

• A localized sharp, tight, or pulling pain between two ribs
• Pain that worsens when taking a deep breath, coughing, sneezing, or twisting
• Tenderness when you press the area
• Discomfort that continues after the run and may last for several days
• A feeling of muscle tightness rather than internal pressure

Pain that is clearly reproduced by pressing on the sore spot or moving your torso is more suggestive of a chest-wall muscle problem. However, this does not completely rule out other causes. A doctor may need to assess persistent or unexplained chest or upper-abdominal pain.

How to tell a stitch from a muscle problem

The two conditions can overlap. A stitch is usually felt under the lower ribs or on the side of the abdomen and often settles fairly quickly after stopping. An intercostal injury is more likely to remain sore afterward and to hurt with specific movements or deep breathing.

Feature	Exercise-related stitch	Intercostal muscle cramp or strain
Typical timing	During running or soon afterward	During or after exercise; may persist
Location	Under the ribs or side of the abdomen	Between or along the ribs
Effect of deep breathing	May hurt briefly	Commonly worsens the pain
Tender to touch	Sometimes, but not always	Often
Effect of twisting	May have little effect	Often increases pain
Recovery	Usually minutes after slowing or stopping	Hours to days, depending on severity

Other causes are possible. Reflux, trapped gas, gallbladder problems, inflammation of the lung lining, infection, and rib injury can all cause pain near the lower chest or upper abdomen. A recent viral illness, forceful coughing, or a fall may point toward a different diagnosis.

What to do during a run

If the pain is mild and feels like a familiar stitch, reduce your pace or walk. Do not try to “run through” severe pain.

You can try:

• Taking slower, controlled breaths, with a longer exhale
• Applying gentle pressure with your fingers to the painful area
• Bending slightly forward while walking
• Relaxing your shoulders and avoiding shallow, rapid breathing
• Stopping if the pain does not improve promptly

For future runs, allow time for a gradual warm-up. Avoid a large meal shortly before running, and notice whether particular foods, drinks, or high-volume fluid intake appear to trigger symptoms. Adequate hydration matters, but rapidly drinking a large amount immediately before exercise may contribute to discomfort.

There is no single proven technique that prevents every stitch. Training progression, good posture, steady breathing, and avoiding hard exercise soon after eating may reduce the chance of recurrence.

When to speak to a doctor

You should speak to a doctor if the pain:

• Keeps returning or is becoming more intense
• Lasts after you stop exercising
• Continues for more than a few days
• Is associated with fever, vomiting, a persistent cough, or unexplained weight loss
• Occurs after an injury or forceful impact
• Makes normal breathing difficult
• Happens during light activity or at rest
• Is new and unexplained, particularly if you have heart or lung disease

A clinician can examine the ribs, chest muscles, lungs, heart, and abdomen. Depending on the symptoms and medical history, they may consider tests such as an electrocardiogram, chest imaging, or blood tests. Most exercise-related stitches do not require extensive testing, but persistent or unusual pain should not be self-diagnosed indefinitely.

For an initial, general guide to possible causes, you might consider a free, online symptom check, using the doctor approved Ubie Symptom Checker. It cannot diagnose a condition or replace an in-person medical assessment, especially when symptoms are severe.

Seek urgent medical help for red-flag symptoms

Call emergency services if lower-rib or chest pain occurs with:

• Severe or worsening shortness of breath
• Fainting, collapse, confusion, or extreme weakness
• Pressure, squeezing, or heaviness in the chest
• Pain spreading to the arm, shoulder, jaw, neck, or back
• Cold sweating, marked nausea, or a racing or irregular heartbeat
• Coughing up blood
• Blue or gray lips
• Sudden sharp pain with significant breathing difficulty
• A known history of heart disease, blood clots, or a recent major operation, long journey, or prolonged immobility

These symptoms can signal a serious heart, lung, or circulation problem and need urgent assessment. Do not assume that pain is “just a stitch” if your overall condition feels seriously wrong.

Bottom line

Pain under the ribs after running is most often an exercise-related stitch or chest-wall muscle cramp, not diaphragmatic ischemia. Pain that is brief, improves with rest, and has no warning symptoms is usually less concerning. Pain that is tender to touch and worsens with twisting or deep breathing may involve the intercostal muscles.

Because chest and upper-abdominal symptoms can occasionally reflect serious heart or lung conditions, speak to a doctor about persistent, recurrent, severe, or unexplained pain—and seek emergency care for any potentially life-threatening symptoms.