Benefits and risks of exercise: From heart-healthy to heartburn

Physical activity is key to healthy living, but if you suspect that your exercise habits are responsible for your GI flare-ups, you may be on to something.

The overall benefits of exercise are astounding. Regular physical activity reduces your risks for obesity, osteoporosis, cancer, depression and cardiovascular and endocrine diseases, just to name a few. When it comes to your GI system, however, the effects of exercise can be more varied. The same morning run that protects you against obesity and fatty liver disease could also be causing your morning heartburn flare-ups. Research on this often mysterious relationship between physical activity and GI function has uncovered as many questions as it has answers, but one thing is very clear: To make the most of your workout and avoid unpleasant GI symptoms, you may need to rethink your exercising habits and tailor your physical activities to your body’s individual needs.

GERD. With symptoms of heartburn (chest pain, regurgitation and chronic sore throat), GERD can become debilitating, especially for athletes, for whom intense physical training is mandatory. But even average exercisers with GERD can find that heartburn intrudes on their workouts.

If you’re wondering what exactly GERD has to do with exercise, you’re not alone. While the scientific community has yet to offer any formal conclusions on the topic, numerous studies have shown that prolonged physical exertion tends to relax the lower esophageal sphincter, the muscle that, when functioning properly, prevents stomach acids from entering the esophagus. When it’s relaxed, however, acid is able to enter the esophagus, resulting in exercise-induced reflux.

Also, some forms of exercise tend to increase GERD symptoms more than others. A study published compared the reflux results from two forms of vigorous activity: stationary biking (representing aerobic activity with little body agitation) and weight training (representing a standard nonaerobic activity with moderate body agitation). Of these categories, the runners experienced the most reflux and the cyclists the least.

These results, and similar findings of other studies, suggest a direct correlation between body movement and acid reflux. In other words, the more movement involved in an activity, the higher the chances of heartburn, chest pain and nausea. These studies also reported a decrease in GERD symptom flare-up when the subjects skipped their pre-workout meal.

What does this mean for you? According to an AGA member, of the gastroenterology section, Veteran Affairs Palo Alto Health Care System and coauthor of Exercise and Gastrointestinal Function and Disease: An Evidence-Based Review of Risks and Benefits, medication may be your best bet. If people have problems with exercise and acid reflux, they should do something to prevent it, such as taking antacids directly before exercising." Regular antacids should be taken within 30 minutes of exercising, while long-lasting drugs and any prescription heartburn medications can be taken earlier.

Doctors also suggest that some GERD patients consider a different activity altogether. If you suffer from a serious case of GERD, vigorous activities such as running or jogging might not be the best choice for you. You may be better off cycling or weight training at the gym.

Last but not least, always keep in mind that eating directly before your workout is asking for trouble. Food stimulates the production of gastric acids and increases the chances of reflux, so be sure to wait at least two hours after a meal before heading for the gym.

Gastrointestinal bleeding. Gastrointestinal (GI) bleeding, like acid reflux, is a condition that frequently affects athletes, especially endurance athletes such as marathon runners. A study published, which examined stool samples from 32 runners before and after the Boston marathon, found that 22 percent of the runners experienced new occult bleeding (blood in the stool) after the race. Researchers also noted that the subject with occult bleeding were the younger, faster runners – the ones who pushed themselves harder during the race and trained more intensely beforehand. Occult bleeding can be a symptom of various GI conditions, but, in these instances, the bleeding was most closely associated with physical exertion. Other studies have shown similar results, demonstrating a strong connection between vigorous physical exertion and GI bleeding.

Chances are, the average exerciser will not be troubled with exercise-induced GI bleeding, but endurance athletes should be wary of unusual fatigue, lethargy or blood in the stool-signs of possible anemia as a result of long-term gradual blood loss. As explained by doctor, in the case of somebody who has bleeding that has been attributed to either a small bowel or colonic source, the bleeding may be exacerbated by the exercise, so they should avoid the exercise that causes bleeding.

Ulcers. Some researchers have hypothesized that high levels of physical activity can also increase the risk of ulcers (sores in the lining of the stomach or duodenum [the beginning section of the small intestine] caused by H. pylori infection or the use of nosteroidal anti-inflammatory drugs). However, research has yet to offer any solid evidence to this effect. In fact, apart from a handful of studies claiming an increased risk of duodenal ulcers in occupations involving manual labor, most studies have actually found that exercise can lower the risk of ulcers.

According to a 2000 study published that involves 10,000 men and women, physical activity significantly reduces the relative risk for duodenal ulcers in men. The researchers proposed that exercise protects the exerciser by strengthening the immune system against infection and decreasing overall acid secretion. However, no protective effect against duodenal ulcers was demonstrated in women, and the occurrence of stomach ulcers was not reduced for women or men.

Inflammatory bowel disease. As with ulcers, many scientists believe that exercise might be beneficial to patients with inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis. Multiple studies have demonstrated that when IBD patients add light-to-moderate exercise to their routines, their symptoms improve. To date, however, no study has proved this protective relationship. As explains, there’s not clear-cut evidence that you can improve IBD through exercise, it’s just the sense of well-being the you may gain.

This sense of well-being, also known as the exercise high, is the reason why so many early morning joggers are willing to hit the pavement while the rest of us are still sound asleep: it helps them face whatever the day might bring. While a heavy workout might leave you physically exhausted, your spirits are soaring, and you’re better able to deal with stress and the everyday pressures of life. For people who suffer from IBD, better stress-coping abilities mean less frequent symptom flare-ups – a blessing by any account, despite the fact that researchers have yet to uncover any scientific explanation for the phenomenon.

Colorectal cancer. Perhaps the most convincing argument for physical activity is its clearly documented protective effect against colorectal cancer, the third leading cause of cancer incidence and mortality for both men and women in the United States. The evidence that exercise has a protective effect against colon cancer is overwhelmingly consistent, and physically active men and women can experience less than half the risk of their sedentary counterparts.

However, as with so many other relationships involving exercise and GI function, researchers are unsure exactly why physical activity lowers the risk for colorectal cancer. Scientists used to believe that exercise reduced colorectal cancer risk by speeding up the movement of food and waste through the digestive system and decreasing the time the dietary carcinogens linger in the colon. More recent research has disproved this theory. Regardless of the reasons why exercise reduces cancer risk, the results are impressive and not to be ignored.

Make your workout work for you. From protection against colorectal cancer to possible prevention of ulcers and reduction of IBD symptoms, exercise has much to offer those of us with GI concerns. If heartburn or other GI issues have discouraged your form participating in physical activities, give exercise another chance. Talk to our doctor, and experiment with preventive medicine or less vigorous workouts. Also, be sure to wait at least two hours after eating to begin exercising, and drink plenty of water during your workout. After all, exercise is key to healthy living, and missing out on the benefits of physical fitness may mean the difference between sickness and health – or in some instances, between life and death.