Gastrointestinal Problems

Motility Disorders

Gastrointestinal motility disturbances affect a significant number of recreational and competitive athletes. Runners report symptoms more frequently than other endurance sports athletes; hence, the term runner's trots is used to describe the stool changes that have been associated with running. Motility disturbances manifest through a variety of gastrointestinal symptoms, including nausea, vomiting, bloating, cramping, urge to defecate, or change in frequency of bowel movements. Lower gastrointestinal symptoms are noted more frequently than upper gastrointestinal symptoms, especially in female athletes, likely due to hormonal changes of the menstrual cycle. Deconditioning in the untrained athlete also seems to lead to increased symptoms.

The precise etiology of gastrointestinal motility disturbances with exercise is unclear. Some theories suggest that muscle enlargement during exercise causes compression of the colon, while others point to decreased blood flow to the colon during exercise resulting from the greater blood flow to the muscles. Other theories identify mechanical and hormonal changes as causing altered transit time of material through the gastrointestinal system. Most likely, the etiology involves multiple factors that may be influenced by the intensity of exercise and hydration status.

Symptoms typically occur during or immediately following exercise and may involve a range of symptoms from abdominal cramping to severe diarrhea with incontinence. A complete history should review any recent travel or unusual food consumption to evaluate for an infectious cause. Symptoms that are not related to exercise activity should raise suspicion for an underlying disorder such as inflammatory bowel disease or irritable bowel syndrome. Evaluation and testing should be directed based on the history and exam findings as well as on the concern for etiology other than exercise. Treatment should emphasize rest until symptoms resolve, as well as proper hydration. Gradual return to exercise is recommended when the symptoms resolve. Antidiarrheal agents should be used with caution as they may increase the risk of heat injury. Avoidance of substances that may worsen symptoms is recommended. Foods high in fiber and fat as well as milk and fruits should be avoided for a few hours before exercise. Protein and herb supplements have also been associated with increased symptoms. Symptoms may be alleviated with bowel and bladder emptying before exercise.

Gastroesophageal Reflux Disease (GERD)

Gastroesophageal reflux disease (GERD) is a condition where the stomach (gastric) contents move up into the esophagus (the muscular tube [Page 578]from the throat to the stomach). The characteristic symptoms include heartburn and acid indigestion, but patients frequently complain of nausea, belching, bloating, cough, or wheezing. Many factors have been identified that contribute to worsening of GERD symptoms, including increasing age, exercise after eating, smoking, a high-fat diet, and weight gain or obesity. Up to 50% of athletes complain of GERD symptoms during exercise, especially if they have had a previous history of GERD. Treatment of GERD begins with dietary and lifestyle modifications. It is recommended to avoid eating within 3 hours of lying down and to avoid large meals. Foods to avoid include caffeine, chocolate, mint, fatty foods, spicy foods, citrus fruits, and tomatoes. Other behavioral changes that may improve symptoms include discontinuing smoking, reduction of weight, and avoiding exercise for 3 hours after eating. Patients who fail to respond to these changes may require additional treatment with medications. Symptoms that persist despite treatment, especially in older adults, require additional evaluation and testing.

...