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Upset Stomach While Running? You May Have Runner's Trots

In 2017, researchers found that 65% of marathon runners (and other endurance athletes) experience gastrointestinal symptoms during exercise. With races being the most common place of all. With numbers that high, it is quite likely that if you are a runner (and reading this article) you have experienced what we call "runner's trots."

By
Brock Armstrong,

Photo of runners waiting for the porta potties

I know, it's a gross topic, I also know that it is one which has affected more than just a few of us avid movers.

Many of us have been there. You are mid-run, not a public bathroom in sight, and suddenly the overwhelming need to find a toilet strikes. The word "urgent" is suddenly redefined for you. At that moment you wrestle with the choice of ducking into a bush (if you are lucky enough to see one), squatting on the side of the road, or just letting it all go, standing right there on the running trail (or race course) and hoping that you get home before the integrity of your running apparel fails you.

I know, it's a gross topic, I also know that it is one which has affected more than just a few of us avid movers. 

In the study called Irritable Bowel Syndrome and Gastrointestinal Issues in Endurance Athletes: Prevalence and Management Strategies, a questionnaire was distributed to athletes in the U.S. who were competing in a marathon, ultra-marathon, half-distance triathlon, or full-distance triathlon in 2016. When the questionnaire was collected and tallied, the results showed that the total prevalence of irritable bowel syndrome among 321 endurance athletes was between 9.0% to 22.1%.

The results went on to show that 10.9% of the athletes reported seeing a medical professional about their GI (Gastrointestinal) issues, and 17.1% had issues which "sometimes or often" interrupted or prevented a training session. Surprisingly, 65.7% experienced at least one lower GI symptom at a frequency of "sometimes or more" during training. Finally, almost half (46.7%) of the athletes had tried nutritional modifications to help ease their symptoms with 19% trying over-the-counter meds.

Why Does Runner's Trots Happen?

To make matters worse, while this is happening, your blood is also being shunted away from your intestines and toward working muscles to provide them with fuel and oxygen.

Running is a jarring sport, and although all of your organs get jostled, it especially jolts your stomach and colon. This repeated movement causes food (and waste) to move around in the GI tract more than it usually would. To make matters worse, while this is happening, your blood is also being shunted away from your intestines and toward working muscles to provide them with fuel and oxygen. This shunting reduces the function of your intestines and can eventually lead to lower GI problems.

Ok, this is all interesting to know, but it doesn't necessarily help us. But a 2018 study from Medicine and Science in Sports and Exercise does offer some potential help in the form of a low FODMAP diet. 

What is FODMAP?

According to my fellow Quick and Dirty Tip-er, the Nutrition Diva, a FODMAP is "an acronym for Fermentable Oligo-, Di-, and Mono-saccharides And Polyols." And the FODMAP diet limits your consumption of nutrients in the carbohydrate family. This includes sugars, sugar alcohols, and some are non-digestible fibers. All things that occur naturally in whole foods such as fruit, dairy, beans, and grains. 

Back to the study. Eleven recreationally competitive runners were enlisted for the trial and asked to complete two, six-day training periods while eating different diets. They were also asked to track and report their symptoms each day, including how they felt while completing intense workouts. At the end of the study, it was concluded that short-term FODMAP reduction may be a "beneficial intervention to minimize daily GI symptoms in runners with exercise-related GI distress."

These results pair well with a study from back in 2016 called Food avoidance in athletes: FODMAP foods on the list where they surveyed 910 athletes to assess behaviors towards self-selected food/ingredient avoidance to minimize gastrointestinal distress. In the athletes whose surveys indicated that high FODMAP foods did indeed trigger gastrointestinal symptoms, they found the main culprits to be:

  • Lactose (86.5%)
  • Galactooligosaccharides (23.9%)
  • Fructose (23.0%)
  • Fructans (6.2%)
  • Polyols (5.4%)

So, if you are someone who has found themselves in this unfortunate situation more than once, you may want to consider avoiding lactose (for sure) and perhaps to a lesser extent other high FODMAP foods to help you have a safe, enjoyable and emergency-free training session or race. 

For more info on FODMAP diets, check out the Nutrition Diva's article called What is the FODMAP Diet?

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