You are a few miles into a run when the urge hits, and the nearest bathroom is nowhere close.
Most runners have been there, even if few admit it out loud.
The urge to poop mid-run is one of the most common complaints in endurance sport, and it is usually fixable once you understand what triggers it.
Here is what you’ll learn:
- Why your gut suddenly wants to empty when you run
- Whether needing the bathroom on every run is normal
- Which foods set off runner’s trots and how to find your own triggers
- How to time your runs, hydrate, and prep for race day so you stay on the road
Why Do You Suddenly Need to Poop While Running?
The main reason you need to poop while running is that your body sends blood away from your gut to your working muscles.
Researchers have found that blood flow to the gut can drop by 80% or more during prolonged or hard running.
When that much blood is diverted away, the digestive tract gets irritated and speeds up its contents to clear them out.
That is why the urge often arrives during faster running or deep into a long run, when the blood-flow drop is largest.
The pounding of running adds to it, because every stride physically jostles your intestines and helps move stool toward the exit.
Stress hormones add to it too, which is why nervous energy before a race can send you looking for a bathroom before you have run a single step.
Is It Normal to Need the Bathroom on Every Run?
Needing the bathroom while running is common, and for most runners it is a nuisance rather than a medical problem.
In one study of a 67-kilometer mountain race, researchers reported that 43% of the runners dealt with gastrointestinal distress during the event.
So if this happens to you often, know that it is common and that it responds well to a few changes.
The urge usually eases as your digestive system gets used to regular running, and the fixes below reduce it further.
If you ever see blood in your stool or feel severe cramping that does not settle after the run, stop guessing and see a doctor.
What Foods Make You Need to Poop While Running?
Food is the trigger you have the most control over, and it is where most runners find their biggest wins.
High-fiber foods, fatty meals, and sugar alcohols are slower to clear your gut, and they are the most common triggers of runner’s trots.
Caffeine and high-sugar sports drinks can also speed things up, and they hit hardest on a sensitive stomach.
Research has shown that a temporary low-FODMAP diet, which cuts fermentable carbs found in foods like onions and wheat, reduces exercise-related gut symptoms, while cutting gluten alone does nothing.
Your own triggers are personal, and the reliable way to find them is to track what you eat against how your gut behaves on the next run.
That matters because a study of 221 endurance athletes found that gut symptoms during racing were most strongly predicted by a personal history of gut problems rather than by one universal trigger food.
Keep a simple food log for 2 weeks, noting your meals and any bathroom trouble on the run that follows, since food can take 24 to 48 hours to move through.
Once you spot a pattern, cut that food before key runs or move it to rest days.
What and When Should You Eat Before a Run?
What you eat in the hours before a run matters as much as the food itself, because timing decides how much is still sitting in your gut when you start.
Leave 2 to 3 hours after a normal-sized meal so most of it has cleared before you head out.
If you only have 30 to 60 minutes, keep the pre-run snack small and low in fiber and fat, such as a banana, white toast, or a plain bagel.
Save the high-fiber breakfast, the coffee-and-eggs combo, or the big smoothie for after your run rather than before it.
A long, hard session needs more care here than a short easy jog, since that is when gut blood flow drops the most.
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How Do You Time Your Runs to Avoid Bathroom Stops?
Timing your run around your body’s natural rhythm is one of the simplest ways to avoid a mid-run bathroom emergency.
Your colon is most active in the first hour or two after you wake, so giving your body a chance to empty before you head out clears the problem before it starts.
If you run in the morning, wake up 15 to 20 minutes earlier so your system has time to catch up.
A warm coffee or tea after waking triggers the gastrocolic reflex and often prompts a bowel movement before you lace up.
Running at the same time each day trains your gut to expect the same schedule, which makes your bathroom habits more predictable over a few weeks.
How Should You Hydrate to Prevent Runner’s Trots?
Staying properly hydrated protects the blood supply to your gut and lowers the odds of a mid-run urge.
When you run low on fluid, reviewers have noted that the gut loses even more of its blood supply, which makes gut symptoms more likely.
The fix is to arrive at your run already hydrated rather than trying to catch up once you are out the door.
Skip high-sugar or concentrated drinks right before running, because the extra sugar draws water into your intestines and can bring on diarrhea.
Plain water or a diluted electrolyte drink is the safer choice when your stomach is prone to trouble.
How Do You Avoid Needing the Bathroom on Race Day?
Race day is the hardest test, because pre-race nerves stack on top of everything else that irritates your gut.
Cut back on high-fiber foods for the 24 to 48 hours before the race so there is less residue in your system at the start.
Eat a familiar dinner the night before and a familiar breakfast on race morning, since race day is the worst possible time to try a new food.
Give yourself enough time before the gun to use the bathroom, ideally after your usual morning coffee.
The most durable fix is to train your gut in the weeks before by practicing your exact race-day food and fluid on your long runs.
Never try a new food or medication for the first time on race day.
Runner’s Trots: Triggers and Fixes at a Glance
The table below sums up the main triggers behind needing to poop while running and the fix for each.
| Trigger | What to do about it |
|---|---|
| Blood diverted from your gut during hard efforts | Ease your pace early and build your mileage gradually so your gut adapts |
| High-fiber, fatty, or sugary foods | Track your triggers and cut them before key runs and races |
| Eating too close to your run | Leave 2 to 3 hours after a meal, or 30 to 60 minutes after a small low-fiber snack |
| Morning runs before your body has emptied | Wake earlier and use coffee to trigger a bowel movement first |
| Dehydration and concentrated drinks | Arrive hydrated and skip high-sugar drinks right before running |
| Race-day nerves and unfamiliar fuel | Cut fiber 24 to 48 hours out and practice your race fuel on long runs |
14 Responses
Another huge part of this that kind of falls into the food category is supplements. If you suddenly decide to drink a cytomax and pop a couple gels before a race and your stomach isn’t used to that… lookout!
This article is very helpful. I sometimes find myself needing a restroom quite badly when running and of course there are no restrooms available when this happens. The two things I have done is first of all to try to bm before going out, although you can’t always force your body to get rid of it if its not ready to. The second thing is to plan the route so that you either have access to a restroom or privacy in nature. For myself my route consists of country fields and wooded areas so I usually don’t have a problem with privacy. I will hold it if I can, but I find it so annoying to have a hard and pushing bm wanting out. If it gets too uncomfortable, I will utilize a secluded area to relieve myself. And yes I always carry tissues with me. I agree, its a topic that is not much talked about but needing a bm when running probably happens to a lot of people and it is good to have these useful tips.
I was looking for tips as this has become a more regular issue. I think it’s a combination of longer runs (excuse the pun) and just the motion (again excuse the pun) of pacing that moves you to need to go. So not to be deterred I am including big stores on route (IKEA – super facilities) and there’s always Supermarkets too. Perhaps it will not always be a problem but despite going beforehand, it’s getting more regular (sorry) – the joys of eating healthy and keeping fit? ;0/
I usually run around my neighborhood, and half way through my run, my body was like, ” yeah , your having a nice run? Well I’m going to f**k it up”
You wrote: write down the foods you eat and then identify your bathroom situation on the preceding run.
Did you mean “following run”?
Very good article, very useful info. Personally i find it is the motion that seems to shake everything loose and we all know the result after that!
Good to hear others experience too, at least i am not the only one looking for a quiet area or the next gas station!!
I have found a product that works! It is called Prev, go to there website @ http://www.preventprevail.com, you will be glad you did!! It is a Natural Solution for Athlete’s G.I. Stress.
Thanks for your feedback Craig. Happy to hear you have found a solution!
Craig DeVitto, Prev sounds ideal, but not available in the UK…We have Immodium but that doesn’t seem to work…If anyone has any other preventative measures that are available in the UK similar to Prev…please let me know….other than that…Thanks for the tips, i shall be trying some of them out..especially the diet….
Hi Paul, thanks for reaching out. I am actually from the UK, and I had many situations where I had an upset stomach during runs. The best solutions I found were to make sure you get up with enough time for your body to get moving and go to the bathroom before you run. I also find having a tea first thing in the morning helps to regulate. Finally, look at what you are eating, try different foods in different times before you run, sticking to plain carbohydrates before the run (even up to 5 hours before). The biggest thing is to experiment yourself, and find out what foods work for you. Try to stay away from fruits and vegetables (or other high fiber foods) before running, and keep the foods as simple as possible. Hope this helps!
I am lucky (?) to run in the early morning in the dark. I have lots of bushes to duck into when the emergency strikes, and I know the location of every porta-potty and 24 hour store in the neighbourhood. Thankfully I don’t need this information every run. I like the suggestion of getting up a little earlier; sometimes that helps.
I’ve completed 57 marathons in 39 years and had to make pit-stops for a BM in at least a dozen of them. Usually the urge comes within the first hour and I can sometimes fight it for another :30 or so until I reach a port-a-potty or public restroom. I’ve varied my food intake and pre-race routine with some success, but now that I’m the course longer, the threat is always there. When you gotta go, you gotta go. I always carry a few baby wipes with lanolin in them rather than t/p. they don’t shred or stick, and the lanolin helps soothe the area. I also carry a small tube of Vaseline to reapply when my “business” is done.
Hi Alan, thanks for sharing what has helped you. Have you practiced your eating in the months before, eating the same foods over and over again (when you find ones that work?). We have some other suggestions that have worked with runners who struggled with this in the past if you would like us to share. We appreciate your suggestions for runners once they do have problems, those really will be very helpful!
I primarily have this problem during my harder efforts or workouts. I’m guessing it’s the added blood flow going away from my GI tract. Normally, coffee is usually able to help me get rid of this problem before regular runs and even long runs, but I haven’t found a solid solution yet for getting rid of this issue during my repeats, tempos, fartleks, etc. I’ve tried toughing it out a few times throughout the duration, but it normally leaves my stomach very upset for the rest of the day and I am in the bathroom every 20-30 min. The other option is to stop the workout and use the port o potty, but I don’t like interrupting the hard efforts. Still looking for a solution.