You’ve changed into your walking or running gear, laced up your shoes and head out the door fully charged for a good walk or run. After a couple of minutes, the feeling starts, but you ignore it and bravely soldier on for a bit.

Then you know what’s definitely going to happen if you don’t head for the nearest bathroom or go home – you need to take a poop!

Your mind is filled with questions. Is the need to poop midway during exercise considered normal? Am I the only one feeling like this? How can I stop this from happening?

Well, let’s go further into this interesting subject.

Does exercise affect bowel movements?

You may be somewhat relieved to know that according to Dr Rudolph Bedford, gastroenterologist at Providence Saint John’s Health Center in Santa Monica, “This is a common issue. We do see patients frequently in our office with it who exercise, especially runners and cyclists.”

Some people might get the urge to poop mid-workout and others may get it post-workout when the effects of exercise can still be felt by the body.

Sadly, not much research has been done on this topic, but an interesting study done by the University of Witwatersrand in South Africa, was published by the journal Gut in 1991. The study was done on 10 participants who did moderate exercise over three one-week periods consisting of cycling on a stationary bike, running on a treadmill, or not exercising at all. Bowel movements of the 10 participants were tracked with trace markers, poop collected, x-rayed and weighed.

It was found that the transit time, i.e., time taken for food to travel through the gastrointestinal tract, differed from 51.2 hours when sedentary, to 36.6 hours when on the exercise bike, and a much shorter 34 hours when running on the treadmill.

Dr Peter Chang, a gastroenterologist (GI) at East Side Gastroenterology affiliated with Mount Sinai Hospital in New York City, offered this explanation on the results: “The study was very objective. It made it clear that physical activity does increase bowel activity, but the physiology as to why is not quite clear.”

GI specialists have some interesting theories on why exercise increases bowel movements:

Fluctuation of hormone levels or a case of nerves:

When you train for a competition or a race, you will naturally experience elevated levels of nervousness or excitedness.

Dr Chang explained, “There have been studies done that show when you engage in physical activity, your hormones change,” A main hormone called the vasoactive intestinal peptide (VIP hormone), comes into play here as it is found to stimulate gut motility. Motility is the ability of the digestive tract muscles to contract, i.e., move food along.

“When you exercise, it can stimulate the release of VIP hormone and therefore increase bowel movement,” says Dr. Chang.

Studies have also shown increased levels of adrenaline and other neurotransmitters can affect gut motility, as they can also have an effect on a peptide hormone, gastrin, which stimulates the secretion of gastric acid and aids in gastric motility.

Dr Chang says “Think about it like this—if you have to escape from a tiger chasing you, you may poop your pants. That’s because of the increase in hormones and neural activity. The nerves that transmit to and from the GI tract are affected.”

Increase in blood circulation:

During exercise, blood normally flowing to the intestines is redirected to the muscles to provide them oxygen. Dr Bedford went on to explain further by saying, “The reaction of the bowel, in this case, is to contract, and a contraction itself pushes things through.”


It is important to remain hydrated before, during and after exercise. On the other hand, however, Dr Bedford has observed and treated long distance runners and cyclists for overhydration. He says, “It’s a mix of drinking too much fluid, especially ones that have electrolytes in them. This can create osmotic perfusion into the colon and small intestine, which can cause loose bowel movements to occur.”

Loose bowel movements normally equate to diarrhea happening at the most inappropriate time.

Simple solutions to avoid pooping during exercise:

First of all, it is important to understand that it is perfectly normal to have the urge to poop mid-way during exercise, though you wish it could be better timed.

Dr Chang’s suggestion is to stay away from drinks that have caffeine as it affects the nervous system and gut.

If you cannot do without your cup of coffee, Dr Bedford aptly offers this advice: “If you want to eat or have coffee before exercising, try to also have a bowel movement before. It will always be to your benefit”.

As usual, this article serves as a guideline on possible causes that make you feel like pooping during exercise. Do consult your doctor for proper advice, as there could also be other related issues that gone unchecked.

By Aaron
11th June 19:20

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