Why Does Running Make You Poop?

Changes in your stool can help identify problems in the digestive system. So, any pooping that’s out of the ordinary might cause you concern. If you’re a runner, you might wonder why being on the go, causes you to go. In other words, why does running make you poop? And, is that normal? Devin RH Smith, MD, UnityPoint Health, helps us understand why activity stimulates gastric motility and things you can try to keep running and bowel movements on course.

Why Does Running Make You Poop?

Dr. Smith assures runner's trot, or runner's diarrhea, is normal. 

“Walking and jogging tend to increase gastric motility and gastric emptying in everyone; this is a physiologic response,” Dr. Smith says. “Movement gets the digestive system moving a little more quickly than if you're sitting still. While it may be inconvenient, it’s never in and of itself a dangerous sign.”

Dr. Smith says there are no clear trends regarding age, gender or training level and needing to have a bowel movement. Moving means more activity in the digestive system, but there's no other specific cause.

“It likely results from a combination of different factors,  including blood distribution between intestines and muscles, hormonal changes, mechanical stimulation of the organs and possible stress or anxiety, especially on a race day,” Dr. Smith says.

Can You Avoid Bowel Movements While Running?

Dr. Smith says the longer you run, the more likely you’ll experience needing to have a bowel movement while running.  

“Prevention is much easier than a cure. Most people can manage their symptoms by scheduling runs after they’ve moved their bowels, avoiding ‘trigger foods’ for up to six hours before a run and ensuring they’re relaxed and well hydrated. If these modifications don’t help, talk with your doctor about other options, including medication,” Dr. Smith says.

Do Certain Foods Trigger Bowel Movements?

Different people have different so-called “food triggers” that might send them to the bathroom during a run. Dr. Smith identifies a few common culprits.

• Sweeteners (natural and artificial)
• Fat
• Grains
• Dairy
• Legumes (peas, beans, lentils, peanuts, etc.)
• Nonsteroidal, anti-inflammatory drugs (acetaminophen and ibuprofen)
• Caffeine

“The best way to determine your individual triggers is to keep a journal. Record the amount, kind and time of food eaten before a run, and note which items and combination are most problematic,” Dr. Smith says.

He also suggests staying properly hydrated and considering how eating during a run makes you feel. He says solids ingested on the race course might be causing you problems, too.

“Again, there's great variation in how people are affected. It’s best to simulate race day by eating what you plan to eat on that  day, to minimize risk of surprise on the course,” Dr. Smith says.

Dr. Smith says food eaten more than three days before the race shouldn’t have any influence on bowel movements.

What Happens When You Feel the Urge to Poop While Running?

Dr. Smith says once you feel the urge to defecate, the stool is already in the rectum. The rectum is part of the lower digestive tract.

“Whether you stop to use the bathroom or push through depends entirely on the confidence in your sphincter (the muscle that keeps stool from releasing). It's not harmful to continue to run with stool in the rectum, but you run the risk of losing control of the situation,” Dr. Smith says.

He also identifies that holding in stool becomes more difficult the more tired you get, experience additional abdominal pressure and/or have thinner consistency of bowel movement. If you happen to experience the inability to hold your stool while running, talk to your doctor.

Does the Consistency of the Poop Mean Anything?

“Bowel movements during a run are no more threatening than at any other time. The consistency isn't important, but color is something you should pay attention to at all times,” Dr. Smith says.

• Bright red stool. Might signal a lower gastrointestinal bleed.
• Sticky, black stool. Can indicate an upper gastrointestinal bleed.
• Yellow stool. Could mean a problem with absorbing fats.
• Light-colored stool. May signify biliary system (gallbladder, liver, etc.) blockage.

Talk to your doctor immediately if you notice any of these changes in your stool.