Physical exercise can be both beneficial and harmful for the digestive tract, and this is proportional to the intensity involved. While mild and moderate physical exercise has a protective effect against colon cancer, diverticulitis, gallstones and constipation, more intensive exercise can induce harmful effects, including heartburn, nausea, vomiting, abdominal pain, diarrhea and even rectal bleeding.

Between one quarter and one half of high performance athletes are afflicted by digestive symptoms that can hinder or disturb their training and competition.

Digestive symptoms associated with such intense practices most often involve problems of gut motility, mechanical factors or modifications in neuro-immuno-endocrine secretions.

Adapted training, a change in lifestyle, a balanced diet, adequate intake of fluids and avoidance of excessive consumption of medication are all strongly advised.

In 70% of athletes, digestive symptoms are linked to practicing intense exercise associated with dehydration. Intestinal ischemia appears to be the primary cause of nausea, vomiting, abdominal pain and diarrhea. The frequency of these problems is nearly two times higher for running than for other endurance sports such as cycling or swimming, and 1.5 to 3 times higher in professional athletes than in amateurs.

So we urge you to use caution!

References
Curr Opin Clin Nutr Metab Care.2009 Sep;12(5):533-8. The impact of physical exercise on the gastrointestinal tract. de Oliveira EP, Burini RC.
Source : Centre for Physical Exercise and Nutrition Metabolism, UNESP School of Medicine, Public Health Department, Botucatu City, São Paulo State, Brazil.