Dietitian Explains Why Athletes Poop At Events Like Hyrox

It’s probably not been the best few days for Joanna Wietrzyk, a Hyrox athlete who recently took first place in a Chinese competition.

The sportswoman, who soiled herself so extensively during the fitness contest that feces were seen running down her legs, has since decided “to retroactively withdraw from the race and forfeit the points I earned”.

Viewers expressed concern about the health risks this caused (much of the equipment used in Hyrox events, like rowing machines, is shared). Hyrox’s policy now states: “If a racer’s blood, vomit, urine, or faeces poses a welfare or contamination risk to the racer or to other racers, a Race Director may withdraw the racer from the race on medical grounds”.

But this is far from the only time an athlete has faced a digestive dilemma during an official event.

In 2005, Paula Radcliffe famously relieved herself during the London Marathon. Runners Mikael Ekvall and Davis Clarke didn’t break their stride after defecating midway through a half-marathon and a marathon, respectively.

And research has shown that gastrointestinal issues affect about 30-50% of athletes, with endurance athletes at extra risk.

Here’s what Kirsten Jackson, a consultant dietitian and founder of The IBS Dietitian, had to say about why this phenomenon seems to be so common.

“What happened at Hyrox may sound extreme, but gastrointestinal symptoms during intense endurance exercise are surprisingly common,” Jackson explained.

“When you’re exercising hard, blood flow is diverted away from the gut towards the working muscles. Combine that with the physical impact of running, dehydration and race-day nerves, and you can experience cramping, nausea, diarrhoea and very sudden bowel urgency.”

Those who push themselves too far for too long could face exercise-induced ischaemic colitis, the dietitian continued, which is different from “regular” runner’s diarrhoea.

In this case, “reduced blood flow to the colon can cause inflammation and symptoms such as significant abdominal pain and bloody diarrhoea, which need medical assessment.”

Jackson said that if she was dealing with an athlete who experienced bowel troubles during exercise, she’d advise them to try a low-FODMAP diet for about 48 hours prior to their race.

“FODMAPs are certain carbohydrates that aren’t always fully absorbed in the small intestine,” she explained.

“They can draw additional water into the bowel and are then fermented by gut bacteria, which can contribute to bloating, gas, loose stools and urgency in susceptible people.”

The NHS has a list of low-FODMAP foods and substitutes (Jackson pointed out that many running gels and sports nutrition products are high-FODMAP).

Still, the dietitian stressed this is not a long-term strategy: it’s just a short-term option for those with sensitive stomachs ahead of a specific event.

In the longer term, “we need to train the gut-brain axis as well as the muscles,” she ended.

“Practising your race-day routine during training – the same breakfast, timings, fluids and sports nutrition – helps train the digestive system, but it can also make the whole routine feel familiar and reduce some of that race-day stress response,” which can itself induce the runs.