This Runner Finished Out a Marathon with Poop Running Down Her Leg

Experiencing GI symptoms during long-distance races is common, as Addi Zerrenner can attest.

runner pooping during marathon
Photo: Getty Images

Runners know that you can do just about everything to prepare for a race, but sometimes, your body has other plans on the big day. Whether you face an unexpected injury or you don't quite hit your target marks, sometimes, sh*t just happens. In the case of one marathon runner, her pre-race meal choice of mushroom pasta led to her running almost an entire marathon with poop running down her leg. And yes, she shared the photos on Instagram in all their graphic glory.

Addi Zerrenner, a 25-year-old running coach and personal trainer, had previously crushed her first marathon back in 2019, but her second try didn't go quite as smoothly, as she told Insider. The Santa Barbara native trained diligently to beat her previous personal record of 2:37:47 at the California International Marathon on December 5, but by the time she hit mile 7, she heard nature's call, explaining she decided to push past it and keep going, all in the name of breaking that PR. (On the topic of poop, here's how to poop the right way — and yes, there's a right way.)

In a scenario straight out of every athlete's worst nightmares, Zerrenner told the outlet that every runner who enjoyed the same mushroom pasta dish as their pre-race dinner fell ill during the run. She explained that she felt healthy and energized at first. When couldn't ignore the urge to go around mile 7, she simply kept running to avoid breaking her stride. Of the untimely situation, Zerrener told Insider that she'd never before experienced digestive issues on race day, adding she thought she was, "finally having the true marathon experience" — though she admitted she "didn't know it was going to be so much."

Zerrenner reveals in the interview that she managed to keep running with a sub-6-minute-mile pace for 21 miles — on pace to beat her personal record — all with soiled shorts and legs, ultimately pooping three times throughout the race. But by mile 21, she said her legs felt like they'd "gained 50 pounds each," though she'd come too far to give up by that point. "I'm not going to drop out with sh*t all over me," Zerrenner recalls in the interview. "I'm going to finish with sh*t all over me." (Psst: Your poop can actually tell you about your health. Who knew?!)

Finish she did, triumphantly coming in 30th place out of 3,133 female runners in just 2 hours, 42 minutes, and 49 seconds. And although she didn't beat her own PR, sharing her, ahem, sh*tty story may help others feel less alone in the gastrointestinal woes they've faced during runs. In fact, if you've ever faced any less-than-pleasant GI issues, such as nausea, cramping, diarrhea, a sudden urge to hit the bathroom, or even blood in your stool, you're far from alone. Multiple studies have found that the majority of long-distance runners have experienced GI symptoms during races, so you're in good company if you've ever needed to stop mid-run and relieve yourself. "In some studies, up to 80 percent of runners experienced GI disturbance, including abdominal pain and bowel dysfunction," California-based gastroenterologist James Lee, M.D. previously confirmed to Shape.

As for how and why it happens, Dr. Lee explained that running (or other exercises that have your stomach jostling around) can cause a few things to happen internally that trigger runner's diarrhea. A surge in cortisol (aka the stress hormone) in your stomach lining can signal that "gotta go" feeling, while stools can loosen due to a shift in mucosal permeability — how easily waste passes from inside your GI tract to the rest of your body — so you'll suddenly feel the urge to poop mid-stride. (Read more: Why Does Running Make You Poop?)

Another unavoidable factor: When you run, your blood flow naturally increases throughout your body to help oxygenate your muscles and keep your body cool, as Christopher P. Hogrefe, M.D., a sports medicine physician at Northwestern Memorial Hospital, previously told Shape. "But what people don't know is that it can decrease the amount of blood flow occurring to the intestines, causing abdominal cramping and potentially the urge to defecate," said Hogrefe.

While unpleasant, plenty of runners know that sometimes you just can't avoid the urge, and if you're competing, you might just find yourself with an unexpected scenario in your shorts. Zerrenner's post-race cleanup was less than pretty, with a teammate's wife wrapping her up in foil blankets, both stuffing toilet paper up their nostrils to block the smell as she ditched her shoes and shorts, according to Insider. But the moment was a testament to Zerrenner's success in letting go of what people think of her appearance as an eating disorder survivor, she says in the interview. She was "walking in the streets of Sacramento pants-less, shoe-less, and with crap all over my legs," she tells Insider, "I'm finally at a point in my life where the only thing I care about what people think of me is the internal." (Read more: Exactly Why You Get a Stomach Ache After a Workout)

After sharing photos of herself with poop running down her legs on Instagram, Zerrenner tells Insider, "the outreach of support and respect I've gotten from people has been overwhelming. I was brought to tears." Of course, she probably had little idea how inspiring her story would be, but it no doubt serves as a reminder that marathon runners are badass… even when sh*t hits the fan (or streets, as it were).

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