In 2001, Gut – An International Journal of Gastroenterology and Hepatology, published a review article from the Netherlands titled “Potential benefits and hazards of physical activity and exercise on the gastrointestinal tract.”
It is an interesting review. It says that acute strenuous exercise may provoke gastrointestinal symptoms such as nausea, heartburn, diarrhea and gastrointestinal bleeding. This happens especially during vigorous sports such as long distance running and triathlons. About 20 – 50 per cent of endurance athletes are hampered by these symptoms. This may deter them from participation in training and competitive events. But it has no long term effect on their health.
In contrast, the article says, repetitive exercise periods at a relatively low intensity may have protective effects on the gastrointestinal tract.
There is strong evidence that physical activity reduces the risk of colon cancer by up to 50 per cent. The primary postulated mechanism, according to the article, is that physical activity reduces intestinal transit time which would limit the time of contact between the colon mucosa and cancer promoting contents.
Several studies have been published on the relationship between physical activity and gall stones. Still more work needs to be done. Regular exercise may reduce the chance of developing gall stones.
A limited number of studies have investigated the preventive effect of physical activity on inflammatory bowel disease (Crohn’s disease and ulcerative colitis). The article says, “While the preventive effect of physical activity remains inconclusive, it has become clear that physical activity is not harmful for patients with inflammatory bowel disease….”
Physical activity in patients with inflammatory bowel disease should be encouraged as these patients have muscle weakness and are at risk of osteoporosis, especially if they are on steroids for the treatment of their disease. Exercise will improve physical health, general well being, perceived stress and quality of life.
A possible role of physical activity in reducing the risk of diverticular disease has been reported in the medical literature. It has been suggested that diverticular disease was more prevalent among people with sedentary occupations than in more active occupations. An increase in colonic motor activity via hormonal, vascular, and mechanical aspects, leading to a reduction in colonic transit time, was postulated as an underlying mechanism.
Regular physical activity and exercise has shown a positive effect on reducing constipation. The review article mentions two case control studies that showed the defecation pattern of runners was “better” (less firm stools, higher defecation frequency, higher stool weight) than in inactive controls. Further research is required to confirm these findings.
In conclusion, strenuous exercise may induce gastrointestinal symptoms such as heartburn or diarrhoea, which may deter people from participating in physical activity. These symptoms are usually transient.
Physical activity, mostly performed at a relatively low intensity, may also have protective effects on the gastrointestinal tract. There is strong evidence that physical activity reduces the risk of colon cancer. Less convincing evidence is found for gall stones and constipation.
Physical activity may reduce the risk of diverticulosis, gastrointestinal bleeding, and inflammatory bowel disease, although up to now there has been little research to substantiate this. Physical activity does not interfere with the healing process in inflammatory bowel disease and will probably not reduce the risk of rectal and gastric cancer, says the article.