That sharp stab under your ribs during a run has a name. Doctors call it exercise-related transient abdominal pain. You call it annoying.

About 70 percent of runners experience side stitches in a given year. In a single running event, one in five participants suffers the condition. The pain stops workouts but rarely signals danger. Younger athletes under 20 report stitches 77 percent of the time versus 40 percent for those over 40.

What Causes Side Stitches

Scientists have debated the cause for decades, but recent research points to one main culprit.
The most commonly accepted theory focuses on irritation of the parietal peritoneum, the nerve-rich lining inside your abdomen. Friction and movement within the torso during repetitive jarring motions irritate this sensitive membrane. When you run, your core muscles engage, causing pressure on nerves and the peritoneum, which triggers stitch pain.

Older theories blamed diaphragm spasms or a lack of oxygen to the breathing muscles. These explanations lost support when studies showed that lung function remained normal during stitch episodes and muscle activity readings remained flat at the pain sites.

What To Do

Before you run:

Eat earlier. Avoid large meals or drinking lots of liquids one to three hours before exercising. Hypertonic beverages are particularly provocative. Finish big meals at least two to three hours before your session.

Fix your posture. Poor posture constricts rib cage expansion and puts excess strain on core muscles. Run tall with shoulders back and chest open.

Strengthen your core. People with a history of stitches show less core stability than those without. Focus on transverse abdominis and obliques twice weekly with side planks, dead bugs, and bird dogs.

Warm up slowly. Walk or jog at an easy pace for 5 to 10 minutes. Let your breathing settle before picking up the pace.

Stay hydrated but skip gulping fluids right before workouts. Find your fluid timing and stick with it.

During a stitch:

Slow down or walk. Most people report relief from deep breathing (40%), pushing on the affected area (31%), stretching the site (22%), and bending forward (18%).

Press the tender spot with your fingers while leaning slightly forward. This supports organs and reduces tension on the peritoneum.

Try side bends with one arm reaching overhead to stretch the affected area.
Focus on complete exhales rather than forced inhales. Take deep belly breaths with your hand on your stomach to guide the movement.

Experiment with exhaling when the opposite foot strikes the ground. Evidence is limited, but many runners find relief.

Safety and Exceptions

Side stitches usually resolve within minutes of stopping exercise. Seek medical care if pain lasts hours after exercise or comes with fever, nausea, vomiting, or chest pressure. Right-sided pain that returns after meals needs medical evaluation.

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Reference Links:

Exercise-related transient abdominal pain (ETAP)

Darren P. Morton; Robin Callister
Sports Medicine, Published January 2015 - Cite this as: Sports Med 2015;45(1):23-35

Click Here for the Study: https://pmc.ncbi.nlm.nih.gov/articles/PMC4281377/7

 

Effect of ingested fluid composition on exercise-related transient abdominal pain

Darren Peter Morton, Luis Fernando Aragón-Vargas, Robin Callister
International Journal of Sport Nutrition and Exercise Metabolism, Published 2004 Apr;14 (2):197-208. doi: 10.1123/ijsnem.14.2.197.

Click Here for the Study: https://pubmed.ncbi.nlm.nih.gov/15118193/

 

Investigation of the side pain "stitch" induced by running after fluid ingestion

B. T. Plunkett; W. G. Hopkins
Medicine & Science in Sports & Exercise, Published 1999 Aug;31(8):1169-75. doi: 10.1097/00005768-199908000-00014.

Click Here for the Study: https://pubmed.ncbi.nlm.nih.gov/10449020/

 

EMG activity is not elevated during exercise-related transient abdominal pain

Darren P. Morton; Robin Callister
Journal of Science and Medicine in Sport, Published 2008 Nov;11(6):569-74. doi: 10.1016/j.jsams.2007.06.006. Epub 2007 Aug 20.

Click Here for the Study: https://pubmed.ncbi.nlm.nih.gov/17703996/

 

Spirometry measurements during an episode of exercise-related transient abdominal pain

Darren P Morton, Robin Callister
International Journal of Sports Physiology and Performance, Published 2006 Dec;1 (4):336-46. doi: 10.1123/ijspp.1.4.336.

Click Here for the Study: https://pubmed.ncbi.nlm.nih.gov/19124891/

 

Influence of posture and body type on the experience of exercise-related transient abdominal pain

Darren P. Mortona, Robin Callisterb
Journal of Science and Medicine in Sport, Published Volume 13, Issue 5p485-488 September 2010

Click Here for the Study: https://www.jsams.org/article/S1440-2440(09)00712-9/fulltext

 

Epidemiology of exercise-related transient abdominal pain at the Sydney city to Surf community run

DP Morton, D Richards, R Callister
Journal of Science and Medicine in Sport, Published June 2005 - Cite this as: J Sci Med Sport 2005;8(2):152-162

Click Here for the Study: https://www.jsams.org/article/S1440-2440(05)80006-4/abstract

 

The effect of transversus abdominis activation on exercise-related transient abdominal pain

Jason L. Mole; Marie-Louise Bird; James W. Fell
Journal of Science and Medicine in Sport, Published 10 July 2013 (Epub) / May 2014 (Print)

Click Here for the Study: https://www.jsams.org/article/S1440-2440(13)00144-8/abstract

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6/24/2005
Updated 9/18/2025