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8 Tips for Avoiding Runner’s Stomach
Because having an accident mid-race is never a fun experience. By Amy Reinink
Runner's stomach occurs when our digestive system experience a large amount of agitation from the act of running or high-endurance exercise. There are certain diet tips you can follow to avoid having an accident mid-run. Photograph courtesy of Shutterstock.
Comments () | Published October 24, 2012

Three years ago, I learned about the dreaded “runner’s stomach” the hard way.

I’ll spare you the gory details. Suffice it to say that no one’s race plan includes running backward on the Marine Corps Marathon course around mile 19 to get to the nearest Porta Potty, then tearfully explaining to the runners waiting in line to use it that if they “don’t let me go next, I will take a crap on the National Mall.”

Not my finest moment. And sadly, I’m hardly alone in suffering a wide range of symptoms of digestive distress mid-run, including vomiting, stomach cramps, and diarrhea. Even Olympian Paula Radcliffe needed a pit stop—and a quite public one, at that—on her way to winning the 2005 London Marathon.

Jared Rice, a registered dietitian, ACSM health and fitness specialist, and triathlete, says there are a couple of reasons runners may be so susceptible to digestive distress, with dehydration and a lack of blood flow to the gut due to exercise being the main culprits.

“The body diverts blood flow and energy focus away from digestion and toward the extremities to fuel the exercise being performed,” Rice says. “Running, being a demanding, full-body motion, may result in more significant diversion of blood and resources.” He also points out that running results in “a significant amount of jostling and agitation to the digestive system, which may further compromise digestive function and result in things moving along more quickly than usual.”

So what’s a runner to do?

Rice says a runner’s diet leading up to and during a race or workout plays a huge role in causing or preventing digestive distress. He’s careful to note that “no one thing will work for everyone, and different people will tolerate habits in different ways,” but says runners with sensitive tummies may want to try the following:

1) Avoid eating large meals within two to three hours of a long run or race.

2) Avoid eating within 30 minutes of starting a run. Instead, sip a sports drink for that final dose of fuel.

3) Avoid heavy, high-fat meals the day of a long run or race, and possibly the night before. Choose light, lower-fiber foods such as bananas, plain oatmeal, or whole-wheat toast.

4) Consider avoiding alcohol, dairy, cruciferous vegetables, and spicy and sugary foods the day of and evening before a run or race.

5) Consider avoiding caffeine the morning of a run or race, as it is a digestive stimulant/irritant.

6) Consider avoiding NSAIDs such as Advil prior to a run, as they can upset the stomach.

7) Be sure to drink plenty of water and optimize hydration for the entire 24 hours leading up to a run or race. Maintain hydration during a long race by drinking two to six ounces of sports drink every 15 minutes.

8) Avoid highly concentrated, sweet drinks such as fruit juice prior to and during a run. A carbohydrate content of more than 10 percent can irritate the stomach. Sport-specific drinks are formulated to be in the optimal range of 5 to 8 percent carbohydrate, and are usually safe for consumption leading up to and during a long run.

Rice says the most important step a runner can take to avoid digestive distress is to experiment with various pre-race meals, sports drinks, and other sports-nutrition strategies during training so they know what will work on race day. “Then on race day, go with your routine!” Rice says. “Don’t try anything new.”

For me, that meant several months of nutritional experimentation, and some surprising results. I found a new favorite pre-race meal: steel-cut oatmeal with a banana or blueberries and some almonds consumed at least two full hours before race time. I discovered a happy surprise: My cherished pre-race “mini latte,” or homemade espresso with a little nonfat milk, sat on my stomach just fine when consumed two hours pre-race. And I discovered that when I started watching my diet two days before a race or long run, not just the day or a few hours beforehand, I could exert a huge amount of control over how my stomach felt on race day.

Have you suffered from the dreaded “runner’s stomach?” What happened? How have you avoided continued problems? Let us know by posting a comment below.

Amy Reinink is a freelance writer whose work has appeared in the Washington Post, Backpacker magazine, Runner’s World, and Women’s Running. She’s also a marathon runner, open-water swimmer, and ski patroller who blogs about her training adventures at


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  • ME

    I just finished (barely) the ultra race Nobel Canyon 50k. Everything was going good, the first 11 miles consists of running up hill and I was doing a great time on my way to finish it in less than 7hrs. but at mile 11at the top of the mtn everything changed, started feeling nausea and my legs felt really heavy, and everytime I tried to run I would feel the need to go to the restroom. When I got to the next aid station (mile16) I was a complete mess, felt disoriented, confused, stomach completely upset. I spend the next hour feeling completely sick and everything was coming from my stomach, it wasn't until I vomited that I felt a little better and started hydrating again and was able to continue, of course my time was 8hrs. 15min.....this is my third straight time that I vomit or feel sick from stomach after a long run all of them were at the mnts.

  • Aishwariya

    It has never happened to me before, so when it happened during a recent half marathon I was shocked. My body betrayed me. All I did was run from one port-a-potty to another.Horrible. I need to figure out why it happened now. Must have been too much diary before the run.

  • AJ

    I feel like I have acidic build up and I'm going to throw up after 5 miles.

  • AM

    Identifying the port-a-potty stops used to me my biggest pre-race fear. I've had more than a few bad cases of "runners stomach." But as soon as I cut wheat/gluten from my diet, that all changed -- plus I soared past my old times and even placed in my first tri. Turns out, carbo-loading the night before a race was the worst thing for me to do. I miss pasta, but not the pain.

  • A comment/correction about Tip #7 - ACSM recommends 3-8oz sports drink every 15-20min. I suggested 2-6oz because I recognize how difficult it can be to consume that much fluid while running. That said, required intake will vary significantly with many factors, including size, gender, level of exertion, sweat rate, outdoor temperature/humidity etc.

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