'Tis the season for indigestion, thanks to the surplus of rich foods and drinks available at this time of year, to which most of us are unaccustomed. For some, this gastrointestinal (GI) discomfort comes but once a year, for others it is an ongoing problem. The type of exercise in which you engage can either alleviate or exacerbate gastrointestinal conditions.

According to a review of the literature, published in the September 2009 issue of Current Opinion in Clinical Nutrition and Metabolic Care, moderate-intensity exercise protects against:

• diverticular disease
• cholelithiasis (stones in the gallbladder or bile ducts)
• constipation
• colon cancer
• inflammatory bowel disease

While on the contrary, bouts of vigorous-intensity physical activity have been associated with a greater incidence of:

• heartburn
• gastroesophageal reflux disease (GERD)
• belching
• abdominal discomfort
• bloating
• nausea
• vomiting
• diarrhea
• constipation
• gastrointestinal bleeding

How does moderate-intensity exercise promote digestive health?

• Facilitates the elimination of waste.
• Helps to maintain a healthy body weight. Overweight and obese individuals are at a greater risk for gastroesophageal reflux disease (GERD) and colon cancer.

Factors related to vigorous-intensity exercise-induced gastrointestinal distress:

• Blood-shunting - blood flow to your GI tract can be decreased by as much as 80% during intense exercise. The reduced blood flow can lead to cell injury and death and inflammation of the mucosal lining of your GI tract. This can result in diarrhea and/or GI bleeding.
• Increased intra-abdominal pressure, especially in football players, weightlifters, and cyclists. This can cause GERD.
• "Bouncing" of internal organs, especially in runners. Vibration from intense exercise can trigger diarrhea and irritable bowel syndrome.
• Altered levels of hormones (neuroendocrine and gastrointestinal peptides) that regulate gastrointestinal homeostasis.
• Dehydration

Tips to improve digestive health and alleviate GI symptoms:

• Engage in regular exercise - routine training provides protection against vigorous-intensity exercise-induced gastrointestinal disorders.
• Maintain adequate hydration to prevent the effects of dehydration.
• Avoid sleeping or laying down within 4 hours after eating. Consider sleeping on two pillows to alleviate symptoms of GERD.
• Avoid intense exercise immediately after a large meal.
• Avoid consuming large quantities of high-fat foods, onions, peppermint, chocolate, coffee, alcohol, and citrus-based foods.

Resource:

Current Opinion in Clinical Nutrition and Metabolic Care, 2009, 12:533-538, "The Impact of Physical Exercise on the Gastrointestinal Tract," de Oliveira, E.P. and Burini, R.C.