How can I prevent runner’s diarrhea?

Written by Dana Sparks and Mayo Clinic Staff of the Mayo Clinic News Network on July 8, 2021

September 1, 2021

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Runner’s diarrhea is characterized by frequent, loose bowel movements during or immediately after a run. Runner’s diarrhea is most common in long-distance runners.

The cause of runner’s diarrhea isn’t clear. Contributing factors likely include the physical jostling of the organs, decreased blood flow to the intestines, changes in intestinal hormone secretion, increased amount or introduction of new food, and pre-race anxiety and stress. What is clear is that food moves more quickly through the bowels of athletes in training.

Often, simple dietary changes can help prevent runner’s diarrhea:

In addition, wear comfortable, loose-fitting clothing when you run. Clothing that’s too tight around the waist may aggravate diarrhea. You might also consider reducing the intensity or distance of your runs until the diarrhea improves. Then gradually increase your activity as your signs and symptoms allow. If these tips don’t seem to help, consult your health care provider for additional suggestions.

Originally posted on the Mayo Clinic News Network.

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