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Home / running coach

Runner’s Diarrhea (Trots): 15 Tips to Treat and Prevent It

Last Updated on March 9, 2023 by Amanda Brooks
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7 Comments

During my time running, I’ve dealt with IT band issues, aches, pains, debilitating calf cramps, even a dislocated rib…but luckily I’ve had the rare experience with the politely named “runners trots” (more accurately named runner’s diarrhea).

For those unfamiliar, this is a generic term to referring to the GI issues experienced by at least 35% of runners during either training or on race day.

Which makes locations of porta potties an important factor in race selection!

It’s no wonder that Bill Rodgers, marathon legend with four victories in both the Boston Marathon and the New York City marathon in the late 1970s said, “More marathons are won or lost in the porta-toilets than at the dinner table.”

I noticed a number of the runners we coach were suddenly on the struggle bus with this particular issue and feeling super embarrassed they kept it to themselves until it was making training a lot less fun.

After lots of research and many ideas, I thought hearing from a few other coaches/runners would help provide some solutions!

(If your issue is peeing while running <<– read this).

Potential Causes of Runner’s Diarrhea

Runner’s diarrhea is characterized by frequent, loose bowel movements during or immediately after a run.

While it’s something that many athletes experience, it is most common amongst long-distance runners (hence the name!).

It’s informally called runner’s trots in the running community and at least a third of all runners have experienced it at some point in time. And if you’re one of those, put the embarrassment to the side and know that your running friends are here to talk about bathroom habits!

The causes of runner’s diarrhea tend to vary from person to person. But we do have some general idea of the potential causes.

While we run, our GI tract experiences repetitive jostling from the movement which can contribute to an increase in farting, diarrhea, and urgency to go.

GI problems can also occur because blood flow to the intestines is reduced while you run since blood flow increases to your muscles instead.

Add dehydration to the mix and it exacerbates the problem even further.

How Long Does It Last?

Runner’s diarrhea doesn’t only mean experiencing loose motions. Symptoms can also include bloating, belly cramps, nausea, vomiting, the urge to go and chest pain.

These symptoms usually come on after you start running and may continue even after you’re done with your run. But keep in mind, it shouldn’t ever last for more than 24 hours.

If you’re experiencing diarrhea and the loose bowel movements won’t stop, it may be indicative of some other medical condition.

So watch out for the following issues:

  • You’re experiencing diarrhea quite often, even when you’re not running
  • There’s blood in your stool
  • You have pain in your abdomen or are experiencing a fever
  • The diarrhea has come on without any particular change in your running habits or diet
  • You feel dizzy, or have fainted or experienced loss of consciousness
  • Your diarrhea has lasted for 24 hours or more

If you’re experiencing any of these symptoms, I suggest it’s best to go seek professional medical advice and get yourself checked out.

Seriously…it can happen to anyone. I doubt that Shalane had “stop at toilet” in her race plan.

runners diarrhea causes
Shalane Flannagan stopping during the 2018 Boston. Image from NBC Sports

When Is It Time to Get a Doctor Involved?

Runner’s diarrhea shouldn’t last more than 24 hours to a couple of days at most and will likely resolve on its own if you follow the tips I mention below.

However, if you experience it very often it could be an indication that there’s some other underlying condition that is contributing to it.

This could be anything from stomach infection to conditions such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) which includes Crohn’s disease and ulcerative colitis.

Working with a doctor can help rule out or in those issues so that you can get it solved for good!

15 Tips to Resolve Runner’s Diarrhea

If you’re suffering from runner’s diarrhea (aka runner’s trots), don’t worry I have you covered.

I’ve done a ton of research and spoken to many fellow running coaches and runners to gather the top 15 tips to avoid runner’s trots or to resolve it once it starts.

Follow these tips and you should be good in no time! But like I mentioned in the previous section, know when to go to the doctor.

You’ll see tips and tricks from running coaches and runners dispersed throughout. I also have some special race day ideas for handling runner trots afterward!runner's diarrhea

Interestingly you will find that most of the dietary tips also help to prevent side stitches and nausea after running!

Tip 1: Limit High Fiber Foods

It’s generally suggested to limit high-fiber and gas-producing foods, such as bran, beans, fruit, and salad at least one day before racing and in any meal immediately prior to run. This is because fiber stimulates the digestive system even further and can increase the likelihood of you having runner’s diarrhea.

I personally believe in keeping an eye on fiber and generally dislike the idea of cutting way down on fiber entirely. I

Fiber has a lot of health benefits, but if this is a major issue for you – see the point below about maintaining a food journal.

“I usually suggest to start increasing the interval between when you consume something and your workout or race. If that does not help, sticking to more refined carb sources in advance of exercise can be beneficial.

While not as nutritious as whole grain sources they are easier for the body to digest…” – Matt Runner Academy

Tip 2: Avoid High Fat Foods

Avoiding high-fat foods is another thing to keep in mind. This is because it takes your body a long time to digest fats, especially when compared to protein and carbohydrates.

For this reason, if you have a high-fat dinner a day prior to running, the food might not have fully digested by then and might still be in your intestinal tract. So when you start running, that food could cause gastrointestinal problems and ultimately diarrhea.

Tip 3: Limit Sweeteners called Sugar Alcohols

You might want to consider limiting or entirely avoiding sweeteners called sugar alcohols before a run as well. These are artificial sweeteners such as isomalt, sorbitol etc are usually present in ice cream, sugar-free candies and gum.

They can sometimes cause a particularly unpleasant condition known as osmotic diarrhea.

This is mainly due to the way they move through your GI tract. Unlike other foods, sugar alcohols can’t be broken down and absorbed by the body and so pass through the GI tract mostly intact and pulling water with them.

By lingering around in your system for so long, they become an easy target for bacteria that go on to feast on them. This usually causes gases and bloating which may trigger your body to try to push it out as quickly as possible.

Now that’s a recipe for disaster, isn’t it? Best avoid them as much as possible.

NOTE: We generally do not see this with Stevia. So if you’re looking for that lower calorie option it doesn’t seem to have that impact.

– think about taking artificial sweeteners out of your diet…Sometimes they can mess with your gut!” – Jess A Pace of Me – as a coach she has found this super helpful to many runners.

runner stomach issues

Tip 4: Be Careful with Energy Bars and Gels

Often energy gels tend to cause gastrointestinal distress. This is because of the massive hit of sugar to the gut, which actually causes it to retain water giving that bloated feeling or that gotta go feeling.

They can be a GREAT tool to help keep you fueled on long runs, but you need to test out what works for you.

Don’t try anything new on race day. This is a very personal mistake to me…ouch.

If runner’s diarrhea is an issue you deal with then checkout these fueling options for sensitive stomachs.

Tip 5: Figure Out If Caffeine is a Friend or Foe

Many runners swear by coffee, then restroom, before their run. Science backs this up by showing that it can help to get your digestive system moving.

But that might not be the case for everyone. Be careful with caffeine though if you do have issues, check out some caffeine-free energy alternatives.

Tip 6: Stay Hydrated

That’s right when you stop sipping water during your run, that could be leading to your gut issues!

Many who report GI issues on the run are dehydrated, which prevents the body from easily moving food through the system, so then as you start running it moves things for you.

  • Drink liquids slowly before, during, and after running.
  • Avoid warm liquids where possible as they can speed food through the digestive tract!
  • And yes once again super sugary sports drinks can cause stomach issues, so beware.

Tip 7: Try Probiotics or Digestive Enzymes

Digestive enzymes!! Probiotics for runners! Two of my go to options when people are having issues.

We know that helping your digestive system work better is HUGE in preventing issues.

Additionally, many who have switched over to the high quality probiotic that I use noticed it helped them get consistent with going first thing in the morning and thus eliminating issues during the run.

Tip 8: Figure Out If You’re Lactose Intolerant

If you suspect you might be lactose intolerant, get yourself checked. If you are, switch to lactose-reduced or lactose-free products before running. The last thing you want is for this to further exacerbate the trots!

I  mention dairy, but honestly knowing if you have any food sensitivities is huge.

Taking out eggs and dairy made a massive difference in my energy levels to run!

It's an embarrassing topic for many, but it happens! Preventing runners trots #runchat Share on X

Tip 9: Maintain a Food Journal

What affects the GI tract for one runner might be different from another.

So keep a food journal to identify those food sensitivities and to see if you’re getting enough fiber to help you go consistently (which should be at least 1 time daily).

“Keep a food log, especially when it comes to seeing what you’re eating right before a run – this will help you figure out what are your best/worst ‘running foods.’ ” – Krissy Murphy

runner porta potty

Let’s move on to some lifestyle focused tips that could also help with your runner’s trots.

Tip 10: Avoid OTC Pain Killers

Avoid over-the-counter pain killers such as NSAIDs (nonsteroidal anti-inflammatory drugs) like Ibuprofen (Advil, Motrin) or Naproxen (Aleve).

A study of ultrarunners showed that those taking it during races started having far more issues with their intestines AND we know it’s harmful to your liver!

Tip 11: Allow More Time for Digestion

Your body needs time to digest food. So try to eat dinner at least 12 hours before heading out for a run. Movement from running will stimulate your bowels and increase the likelihood of you having runner’s diarrhea.

If you need some hard and fast rules about how much to eat and how long to wait after eating to exercise, I’ve detailed that.

Tip 12: Slow Down Your Pace

If you feel that the trots are coming on, slow down. It’ll give you more control over the urgency if you slow down or simply stop running instead of pushing through.

Sometimes that break could give your system time to calm down and you’ll be able to resume running.

It can also affect your running form and potentially hurt you if you’re running with your cheeks clenched.

“Ease your pace up…things calm down…drinking some easy to digest liquid!” – Erica Gorman

Tip 13: Be Patient with Your Body

If you’re experiencing runner’s trots, then I know it’s super frustrating and you want to put an end to. But this is going to be a processing of testing out all the things to see which one is causing you issues.

As a new runner, you may also just need to allow your body some time to adapt to this new activity.

“Be patient, often “the trots” go away, or get better after you’ve been running for a while, and eliminate fiber-rich foods the night before a big run.” – Lisa RunWiki

Tip 14: Use the Bathroom Before a Run

I meant it sounds obvious, but we’re talking about getting up earlier or pushing your run back if needed.

Give your body time to…eh hem go before you head out in the morning.

If you can find a way to create a routine, you’ll see your body soon goes every morning like clockwork. Try training at different times of day to see if that impacts your bathroom process.

hilarious porta potty

Tip 15: Calm the Nerves

Running causes the release of all kinds of hormones, one in particular is cortisol, which can indeed affect our digestive system. Cortisol can contribute to that urge of needing to go.

Anxiety and pressure on race day can add a whole new element to it as well.

So especially on race day, it’s really key to have a routine and a process that helps you to not completely eliminate nerves, but to manage them appropriately.

Read more on 9 tips to manage race day nerves >>

For those of you who prefer to watch your tips, I’ve talked more about my top 9 in this video!

 

Since I think race day deserves it’s own discussion, a few immediate tips!

Race Day Ideas for Handling Runner Trots

Some runners are fine in training and find that on race day they have GI issues, usually due to increased nerves.

Following are a few factors and solutions, plus check out these tips to reduce race day nerves.

Keep it Simple

Stick to gels you have tested during training. Try to train with the gel or drink they will have on the course or start using whole foods, anything that has helped your body know what to expect.

The sudden influx of a sugary gel when you haven’t used them previously is a great way to find yourself seeking a bush.

Get up Early

Give yourself and your body time to get things moving well before the start line. Same as above, eat the meals you’ve been eating throughout training not just on race morning, but the day before as well.

My worst race experience ever was when I got crazy and had fried catfish the day before…oye.

Reduce Stress

The added stress of race day can cause issues due to changes in digestive enzymes. So in the days before, try to spend a little extra time in restorative yoga, meditation, or anything quiet and calming.

Travel Planning

Many find they are backed up after traveling, so consider taking some green powder or drinking a detox-type tea (or my favorite Calm Magnesium drink) the first night you arrive to ensure you go. Then stick to known foods the days before the race.

What about Imodium for runners trots?

This over the counter medicine is used to help stop runners diarrhea by slowing the movement of food through your intestines. Many runners swear by taking a does prior to long runs or races and the side effects generally seem mild (like constipation), but it should be considered an option…not a solution.

It can also take up to 48 hours to work, so if you’re trying it for the first time on race day there are no guarantees.

Like any pain reliever, your best bet is to figure out the cause rather than trying to mask it.imodium for runners

I’ll add to all of this, don’t be embarrassed!

One of the things I’ve learned over the years is that runners have no problem with bathroom talk! Mostly because we’ve all experienced a time where we nearly became the mad pooper.

It’s not the same when you have to deal with it frequently, and I understand that, but know your running friends will be supportive and try to plan routes that will work best for you.

What helps you avoid bathroom issues while running?

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Amanda Brooks
I am a running coach with over a decade of experience helping thousands of runners to achieve their goals from running injury free to crossing that marathon finish line with a PR. I’ve run over 28,000 miles in my own running journey since 2002. Run To The Finish is my place to share that love and my deep dive in to researching all things running. I hold multiple run coaching certifications, as well as a personal training certification. But it’s my ongoing desire to learn and progress as a coach that has allowed me to help runners from their 20’s through their 70’s! More ways to connect with me:
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Reader Interactions

Comments

  1. Sandra Laflamme

    May 10, 2017 at 12:16 pm

    Runners trots are the worst! Thankully I have a mostly iron stomach although one time I drank Kombucha pre-run . . . not good! Great tips! Thanks Amanda!

    • amanda

      May 10, 2017 at 4:23 pm

      ohhh Kombucha, yup wouldn’t have thought about that but it could totally cause some issues!

  2. Sue

    May 11, 2017 at 10:37 am

    I would say that I have the ‘runner’s race’ versus the ‘trots’! Every.single.time I run (ok there are a few exceptions – but not many) I get this …..ABOUT 15% of the time its ‘normal’ diet issues…the other 85% of the time it’s ‘ischemic colitis’ (think nasty nasty and immediate porta potty requirement!). So I ‘own’ it – I locate washrooms ahead of time on my routes, I give my run buddies heads up – if they want to keep running – keep running – if they want to wait for me – wait for me – no harm no foul! By doing this they also know I might need a ‘cover’ if there’s no porta potty around …. (I also try not to push it too hard to invoke the issue) . It does happen to us all !

    • Jenna

      June 1, 2017 at 1:00 pm

      Sue,
      I completely understand! My first half is this weekend and my running partner has already been warned! I have had IBS all my life and find it so invigorating to own all of the glory that comes with it. ;)

      Amanda, this was a great article. and I LOVE your site Thank you for sharing!

    • Val

      September 25, 2017 at 7:21 pm

      The ONLY thing that works for me is UCan pre-workout mix. I’ve tried eating real food of all kinds, various different gels (including all natural ones) and I have GI issues just like you every time I run.

  3. Emily

    May 13, 2017 at 8:02 am

    I find that one of the biggest things that causes runner’s trots for me is probably nervousness on race morning. I used to have them a lot when I first started running; I love what Lisa of RunWiki said, because it’s true. I think they often go away the longer you’ve been running. The advice about fiber and eating a big meal far enough ahead of a race (while eating snacks later) is really good advice too.

  4. mark

    May 19, 2017 at 9:40 am

    Your article is amazing. There are countless theories on the Internet about why running can wreak havoc on the GI system. A lot have little basis in science, and some chat-room tips but all of them aren’t so wise like yours. I think Sometimes runners get diarrhea because their guts are in overdrive—usually before a race, when nerves play a major role. Keep it up

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