Joanna Wietrzyk’s reported bowel accident at HYROX Beijing has put runner’s diarrhoea in the spotlight. Why does it happen, and when should an athlete stop?
Most people arrive at a fitness race expecting sweat, sore muscles and perhaps some questioning of their life choices. Losing control of their bowels is rarely on the list.
Yet reports of a bowel accident involving Australian athlete Joanna Wietrzyk at HYROX Beijing have pushed precisely that possibility into the spotlight. According to coverage, she continued competing after the incident, prompting debate about hygiene and whether the race should have been interrupted. The medical cause has not been established.
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It is an uncomfortable subject, made considerably more uncomfortable by an audience with smartphones.
But for anyone who has abruptly abandoned a run in search of a toilet, the underlying problem may feel familiar.
What Is Runner’s Diarrhoea?
Runner’s diarrhoea refers to frequent, loose bowel movements during or immediately after running. Sometimes called “runner’s trots”, it is most commonly associated with long-distance running. Several factors may contribute, including physical movement, reduced blood flow to the intestines, dietary choices and pre-race anxiety.
The urgency can turn a carefully planned session into a search for the nearest available cubicle. For someone racing in front of spectators, it also creates a distressing decision about stopping, seeking help and potentially withdrawing.
Understanding why it happens starts with what exercise asks of the body.
Why Does Exercise Upset the Gut?
During strenuous exercise, the body redirects blood towards working muscles, reducing the supply available to the gastrointestinal tract. At the same time, running repeatedly jostles the abdomen, while changes in nervous-system activity can alter digestive function.
Add dehydration, and the situation can worsen. Reduced circulating blood volume can further compromise blood flow to the gut, increasing the likelihood of nausea, abdominal discomfort and diarrhoea. Heat adds another challenge, particularly during prolonged exercise.
For runners training outdoors in Singapore or Malaysia, this makes fluid planning relevant to digestive comfort as well as performance.
Pre-race nerves may also contribute. Unfortunately, being mentally determined to finish does not give someone complete control over these physiological responses.
Your Race-Day Breakfast Deserves Some Attention
A familiar breakfast can feel very different when followed by strenuous exercise.
Meals high in fat, fibre or protein close to activity may increase gastrointestinal symptoms. Highly concentrated sugary drinks can also draw additional water into the bowel, aggravating diarrhoea in susceptible athletes. How much someone eats, and when, matters alongside the food itself.
That pre-race kopi is worth considering too. Caffeine, sugar alcohols in some sugar-free products, and energy gels or bars can contribute to bowel trouble. Introducing an unfamiliar gel on race day adds an avoidable unknown.
Painkillers deserve attention as well. It is cautioned that non-steroidal anti-inflammatory drugs, including ibuprofen and naproxen, can increase gastrointestinal complaints.
Can You Train Your Gut?
There is value in rehearsing the less glamorous parts of racing.
A 2025 joint position statement from Sports Dietitians Australia and the Ultra Sports Science Foundation identifies gut training, appropriate hydration and individual dietary adjustments among strategies that can help manage exercise-associated gastrointestinal symptoms.
Gut training involves practising food and fluid intake around exercise to improve tolerance. The study authors emphasise individual assessment, because similar symptoms can have different underlying drivers.
In practice, use training sessions to establish which meals, portions and fuelling routines you tolerate. Keep notes on symptoms and discuss recurring problems with a sports dietitian.
Your teammate may swear by a particular breakfast. Your digestive system gets a vote.
When Should You Stop Racing?
Months of preparation can make withdrawing feel disproportionately difficult. There may be travel expenses, a finishing time to chase, or friends waiting at the finish line.
Those pressures do not make worsening symptoms safer.
If diarrhoea develops, stop to access a toilet and assess how you feel. Seek the race medical team if it continues or you feel unwell.
Severe abdominal pain, blood in the stool, black tarry stools, confusion or signs of dehydration require prompt medical attention. Warning signs of dehydration include dizziness, extreme thirst, dark urine and passing less urine than usual. Adults should also seek medical advice for diarrhoea lasting more than two days, high fever or six or more loose stools daily.
Recovery includes replacing lost fluids and electrolytes; oral rehydration solutions are one option. Antidiarrhoeal medicines should not become an automatic strategy for finishing: they are generally unsuitable when diarrhoea comes with fever or bloody stools.
When a Personal Accident Affects Shared Equipment
An involuntary bowel accident deserves a humane response. In a shared sporting environment, it also requires a practical one.
A video cannot establish whether someone has an infection. However, faecal contamination needs attention regardless of how the athlete is placing.
The US Centers for Disease Control and Prevention recommends prompt cleaning and disinfection after diarrhoea or vomiting. Norovirus is one possible infectious cause, and hand sanitiser alone does not work well against it. Soap-and-water handwashing remains essential.
For organisers, a sensible response would include helping the athlete access medical support and washing facilities, restricting access to affected equipment, and arranging appropriate cleaning before reuse.
HYROX’s Response Leaves Health Questions Hanging
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In its statement following the Beijing incident, HYROX praised athletes’ “courage, resilience and refusal to give in”, before acknowledging that its protocols for elite competition and mass participation had become “blurred”.
That is an uncomfortable framing when the concern is whether someone should have stopped.
The statement confirmed that medical and biological contamination procedures existed. It did not identify which procedures applied in Beijing, explain why the athlete continued competing, or specify changes following the incident.
Separately, HYROX China said it had isolated and disinfected affected areas, removed equipment, and arranged carpet replacement and further cleaning. That account describes the response to contamination, but provides little detail about the decisions taken during the race.
The question remains: at what point should officials have intervened?
A commitment to athlete welfare should include the competitor who becomes unwell, the person using the equipment next, and the staff managing the aftermath. Protecting all of them requires clear decisions in the moment.
What would you need to hear from HYROX before feeling confident at your next race?
