How fast must you trot? Vigorous exercise and diarrhoea

Roy J. Shephard


Objective. To define the prevalence of exercise-induced diarrhoea, to consider its possible causes, and to suggest appropriate management by the coach and the sports physician.

Methods. Information on exercise-induced diarrhoea in the endurance athlete has been garnered by a detailed search of Ovid/Medline, Pub-Med and Google Scholar data-bases.

Results. The prevalence of exercise-induced diarrhoea is greater in the young than the elderly, and in women rather than men; the risk increases with the intensity of effort, but is diminished by training. Endurance running is the activity most commonly implicated, with as many as a half of participants in running events passing a stool during competition at least once during their career. The problem can also occur, although less frequently, during or following bouts of long-distance cycling and skiing. Exercise-related diarrhoea can also occur in patients with inflammatory bowel disease, irritable bowel disorder and following abdominal irradiation for prostate cancer, although the problems in such individuals are usually precipitated by a much smaller volume of physical activity. Factors contributing to exercise-induced diarrhoea may include an inappropriate diet, mechanical stimulation of the colon, visceral ischaemia, exercise-induced hormonal changes, and pre-race stress and anxiety. After excluding more serious underlying pathologies, the management of exercise-induced diarrhoea stresses an optimization of diet, enhancement of physical condition by cross-training, emptying of the colon before competition, and provision of adequate toilet facilities along the race route. Moderate doses of loperamide may be considered for individuals with persistent problems.

Conclusions. Exercise-induced diarrhoea is a potential problem for many active individuals. The resulting social embarassment can have a negative impact upon motivation to engage in regular endurance activity, However, with appropriate management, difficulties can be minimized and most athletes can reach desired levels of physical activity.


Irradiation; Inflammatory bowel disease; Irritable bowel disorder; Marathon; Prostate cancer; Running; Triathlon; Ultramarathon

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ISSN: 19206216