Exercise-Related Diarrhea

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Do you have problems with loose stools or diarrhea after working out? This symptom is so common that it has a cute name: "runner's trots." But while exercise-related diarrhea is common in runners, it can happen with other types of exercise, too, especially with workouts that are vigorous or long-lasting.

Walking and running are good for maintaining regular bowel movements, which is one theory to explain why research shows a decreased incidence of colon cancer among those who regularly walk and run. However, it's also possible to have too much of a good thing. Learn why exercise-related diarrhea happens, what to do when it occurs, and how to prevent it.

Symptoms of Exercise-Related Diarrhea

You may experience cramping, nausea, flatulence, or diarrhea during or after your workout. Exercise can induce stomach pain and an extremely urgent need to defecate. Some people may also have other gastrointestinal symptoms, such as gas, reflux, or vomiting, instead of or in addition to diarrhea.

If you're experiencing diarrhea after working out, you're not alone. An estimated 30% to 90% of runners have reported experiencing runner's trots at some point. Walkers, especially those who walk briskly at a high heart rate, can have the same symptoms.

Causes of Diarrhea After Workout

No single cause of exercise-related diarrhea has been definitively identified. Runner's trots may be caused by different factors for different people. One theory is that the simple up and down jostling of the body during exercise—especially high-intensity exercise—can stir the bowels. Alternatively, blood flow could be to blame as blood flow to the intestines is diverted to your legs during walking and running and that may contribute to cramping and diarrhea.

Underlying irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) may be brought to light by the additional stress of exercise. Dehydration on long walks and runs can also cause diarrhea. Exercise may also exacerbate symptoms of lactose intolerance. The same goes for fructose intolerance. If this applies to you, it may be good to know that fructose is in some sports drinks, as well as juices and fruit.

Treatment and Coping

If and when symptoms of exercise-related diarrhea occur, it's important to address your symptoms and support your body's recovery. First, make sure you're hydrating well. Both exercise and diarrhea can be dehydrating, causing water and electrolyte loss, which can make symptoms worse. Stick to clear liquids, like water, broth, and electrolyte-rich sports drinks (preferably those free of fructose and artificial sweeteners).

You may also benefit from following a bland diet until symptoms subside, focusing on foods like bananas, rice, applesauce, and toast. Probiotics in the form of naturally probiotic foods or supplements may also be worth incorporating. Diarrhea can disrupt the balance of healthy bacteria in your gut; probiotics can help replace and rebalance. If, however, you find that your symptoms don't last a long time, patience and time may be the best option.

Exercise-related diarrhea can't always be prevented, so learning how to cope with runner's trots may help you in the long run. Design your walking and running routes to include a restroom stop at the time when diarrhea usually hits (say, half an hour into your run). Carry toilet paper and hand sanitizer with you during your walks and runs, and don't forget to pack your water bottle.

When to See a Doctor

While runner's trots are common, exercise-related diarrhea is a symptom to discuss with your doctor at your next checkup. If you encounter it frequently and you have other digestive symptoms, make an appointment to have these issues checked. It might be a sign of irritable bowel syndrome or other functional digestive disorders.

While the details might be embarrassing, you will only get a good diagnosis by giving a full and frank history. Keep notes on your episodes of runner's trots so you will have good data to give your doctor.

Prevention

There are also strategies that may help reduce your bouts of runner's trots and exercise-related loose stools. Experiment to see what works for you.

Some people find that temporarily avoiding high-fiber foods in the days before a long race can help prevent symptoms, so save the beans and roughage for future healthy meals. Consider following a low-residue diet the day before a race or long walk, which focuses on food that's low in fiber, such as white bread products and eggs.

Pay attention to what you're drinking. Avoid caffeine and warm fluids, as they can speed up the movement of waste through the intestines. Limit dairy products or use Lactaid when enjoying dairy products, especially if you know you're lactose-intolerant.

Though many people fare better with a healthy snack or light meal prior to exercise, if you regularly experience runner's trots, experiment with the timing of your pre-run snacks and meals. Try not to eat within two hours before your workout, as the presence of food in your stomach may make things worse or set off symptoms.

Don't eat any foods that you know produce flatulence or loose stools for you. There are some that are common culprits like beans, apples, peaches, carbonated drinks, and cruciferous vegetables (cabbage and Brussels sprouts, for example). But you may find that you tolerate some foods better than others.

Know your bowel habits and try to schedule your workouts for immediately after your usual bowel movement time. You may want to start keeping notes if you haven't previously paid attention to your body's natural rhythm.

Have a plan B in place. If all other precautions fail or you know toilets will not be readily available, use an OTC anti-diarrhea product such as Imodium (loperamide). Studies have shown the drug reduces exercise-induced diarrhea in triathletes prone to it. While some medications like Imodium (loperamide) may help, you may want to steer clear of others—like non-steroidal anti-inflammatory drugs (NSAIDs)—before your workout.

Everyone is different when it comes to which foods, drinks, medications, and even exercise routines may trigger symptoms. For this reason, it's important to know what works for you and what doesn't, and only avoid nutritious, high-fiber foods temporarily.

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