Some types of exercise are more likely to cause diarrhea after working out than others. People can help prevent diarrhea after exercising with some treatments, strategies, and diets.

Working out may cause people to have several gastrointestinal symptoms, including diarrhea.

People with diarrhea pass stools three or more times a day. Acute diarrhea may last for 1–2 days before going away. Other forms of diarrhea may last for weeks or become chronic.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, about 179 million cases of acute diarrhea happen in the United States each year.

Physical activity is when a person moves to work their muscles and uses more energy than while resting. People often work out to enhance their health. Certain forms of exercise may make people more likely to have diarrhea.

This article discusses the connection between diarrhea and physical activity and the causes of diarrhea after exercise. It also discusses management and prevention tips, plus when to speak with a doctor.

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As people exercise, their bodies respond in several complex ways. Some of these responses can affect their gastrointestinal system’s functions, including digestion and waste excretion. The bodily responses to exercise can include:

  • Redirected blood flow: When a person exercises, blood flows to their muscles, limbs, and circulatory system instead of their digestive system. This can cause diarrhea.
  • Hormonal activity: Chemicals called hormones regulate different bodily functions. During exercise, a person’s body releases some hormones that reduce the capacity of the gastrointestinal system.

Exercise can also affect the organs in a person’s abdomen through physical effects such as:

  • jarring, jolting, or sudden impacts
  • a person’s body position
  • friction

These effects may lead to a person having symptoms, including diarrhea. Scientists call these symptoms exercise-induced gastrointestinal distress (EIGD) or exercise-induced gastrointestinal syndrome (EIGS).

Types of exercise that cause EIGS

Diarrhea from EIGS often affects people during endurance exercises, such as long-distance cycling or running. Other types of exercise that put pressure on a person’s digestive organs may cause gastrointestinal symptoms, such as diarrhea. These types of exercise can include any that work out a person’s abdominal muscles.

Pregnant people often have diarrhea and other gastrointestinal conditions. Exercising may make diarrhea symptoms worse. Pregnant people with diarrhea should treat it as soon as possible to maintain fluid levels.

Dehydration

Exercise can cause people to lose water and fluid through sweating. They may have an electrolyte imbalance if they do not replace these fluids through hydration.

Electrolytes are salts and minerals in a person’s blood. There appears to be little recent scientific investigation into electrolyte imbalance and diarrhea. However, losing water and fluids through exercise can cause dehydration and diarrhea.

Learn more about dehydration and diarrhea.

Scheduling workouts after bowel movements may help a person manage diarrhea. People can also reduce the intensity or duration of their workouts. In a 2022 study of EIGS in runners, scientists found that running further distances increased how often a person had diarrhea.

Food

Easily digestible foods can help people manage diarrhea. Diets such as the bland diet include easily digestible foods. These foods are low in fiber and have a soft consistency. They do not irritate a person’s digestive system.

The bland diet does not have raw or uncooked foods. Instead, it includes:

Learn more about hydrating foods.

Medication

Some over-the-counter medications can aid people when they are managing diarrhea symptoms, including:

Only certain kinds of infectious diarrhea are treatable. However, people can avoid some foods that may make their diarrhea worse, such as:

  • beverages containing alcohol
  • foods or beverages containing caffeine
  • dairy products, such as:
    • milk
    • cheese
    • ice cream
  • fatty or greasy foods
  • high fiber foods
  • carbonated drinks
  • spicy foods
  • fruits, such as:
    • apples
    • peaches
    • pears
  • foods or drinks containing fructose
  • drinks or products that contain sweeteners, such as:
    • sorbitol
    • mannitol
    • xylitol

Some medications can irritate or injure a person’s gastrointestinal system. Taking nonsteroidal anti-inflammatory drugs (NSAIDs) before exercise can increase a person’s risk of diarrhea. Some common NSAIDs include:

Wearing loose-fitting clothing during exercise may help a person avoid diarrhea. Tight-fitting clothing may limit blood flow to a person’s digestive system, causing diarrhea.

However, there appears to be little recent research into clothing that can help prevent diarrhea after or during exercise. Some research from 2022 suggests that wearing compression socks may help promote abdominal blood flow and reduce EIGS.

Learn more about how to stop diarrhea fast.

If diarrhea causes a person severe dehydration, it can become dangerous. Diarrhea may also be a symptom of a more serious condition. Adults should seek professional medical attention immediately if they have:

  • diarrhea that lasts for more than 2 days
  • a fever of 102oF (39oC) or greater
  • frequent vomiting
  • six or more loose stools in a day
  • severe pain in both or either of their:
    • abdomen
    • rectum
  • stools that are black and tarry
  • stools that contain blood or pus
  • dehydration symptoms

Some forms of physical activity, such as endurance exercise, can make a person more likely to have diarrhea. People can prevent diarrhea after working out by avoiding certain types of food and clothing. They can also manage diarrhea with medications and workout scheduling strategies.

Diarrhea may cause dehydration. It can also be a symptom of a more serious condition. People should seek professional medical advice if they have certain diarrhea symptoms.