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Reduce Your Risk of Runners' Diarrhea


Updated August 09, 2012

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Runners' diarrhea is the term for the group of diarrhea-related symptoms brought on by intense or prolonged exercise. This decidedly unpleasant phenomenon may manifest itself through intestinal cramping, loose and frequent stools, fecal incontinence, and (on rare occasions) rectal bleeding. These symptoms may appear during or after exercising and are most common when the exercise type is that of long-distance running.

Avoid Known Triggers

There are several identifiable factors that affect your gut’s motility, thereby increasing the frequency of intestinal contractions and resulting in diarrhea symptoms. Thus the basic recommendations for reducing the risk of runners' diarrhea have to do with avoiding these factors:

  • Don’t eat two hours before exercise.
  • Avoid caffeine and hot drinks on the day of exercise.
  • Avoid fatty and gas-producing foods starting the day before.

Avoid Other Contributing Factors

Research performed on marathon runners has pinpointed other potential contributing factors for runners' diarrhea. The following appear to result in changes within the gastrointestinal system, changes that increase the risk of diarrhea symptoms:

  • Don't take aspirin or ibuprofen. If possible, avoid these products prior to or during exercise.
  • Stay hydrated. Adequate fluid intake is important for many aspects of health and performance while exercising, including reducing your risk of GI symptoms.

Nervous Diarrhea

Nervous diarrhea is the term for diarrhea symptoms that are experienced prior to intense exercise. You may be more at risk for nervous diarrhea if you suffer from irritable bowel syndrome (IBS), are lactose intolerant, or suffer from irregular bowel habits. Here are tips for avoiding nervous diarrhea:

  • Avoid dairy products if you think you may be lactose intolerant.
  • Learn relaxation exercises to keep your system calm prior to exercising.
  • Schedule your workouts during times when you know that your digestive system is quieter.


Lambert, G., Boylan, M., Laventure, J., Bull, A. & Lanspa, S. “Effect of aspirin and ibuprofen on GI permeability during exercise.International Journal of Sports Medicine 2007 722-726.

Lambert, G. et.al. “Fluid restriction during running increases GI permeability.International Journal of Sports Medicine 2007 29:194-198.

Smetanka, R., Lambert, G., Murray, R., Eddy, D., Horn, M. & Gisolfi, C. “Intestinal Permeability in Runners in the 1996 Chicago Marathon” International Journal of Sport Nutrition and Exercise Metabolism 1999 9:426-433.

Sullivan, S. & Wong, C. “Runners’ diarrhea: Different patterns and associated factors” Journal of Clinical Gastroenterology 1992 14:101-104.

DISCLAIMER: The information contained on this site is for educational purposes only and should not be used as a substitute for diagnosis or treatment rendered by a licensed physician. It is essential that you discuss with your doctor any symptoms or medical problems that you may be experiencing.

  1. About.com
  2. Health
  3. Irritable Bowel Syndrome (IBS)
  4. Diarrhea Tips
  5. Exercise
  6. How to Prevent Runners' Diarrhea

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