Hyrox Now Has a Rule About Bodily Fluids. In Hard Training, Bowel Leaks Are Common, and Mostly Gas
Hyrox added a bodily-fluids clause to its rulebook two days after its Beijing race, and the internet made it a scandal. The research nobody printed says bowel-control symptoms are common in people who train hard, most of what gets counted is gas, and sports medicine already has a way of working through it.
Hyrox's 2026-27 rulebook now lets a Race Director withdraw a racer on medical grounds if their blood, vomit, urine or faeces poses a welfare or contamination risk, recorded as a DNF; it was added on September 14, 2026. Research on athletes shows bowel-control symptoms are common in hard training: in a French study of 393 women, 14.8% of those training more than eight hours a week reported anal incontinence versus 4.9% of others, and 84% of it was gas. Surveys put anal incontinence symptoms at 34.0% of women runners and 27.7% of women CrossFit athletes, and a Norwegian survey found it, mostly gas, in 61.8% of male powerlifters and weightlifters. Pelvic-floor physiotherapy and sports-dietitian strategies are the standard ways athletes work on it.
Hyrox’s rulebook for the 2026–27 season has a sentence it did not have at the start of September. Under section 12.3, “Did Not Finish,” it now reads: “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, in line with HYROX’s medical and hygiene SOPs. Any such withdrawal is recorded on the leaderboard as Did Not Finish [DNF].” The English singles rulebook that carries it was last updated on Monday, September 14, two days after a race in Beijing in which the winner of a women’s pro category had an episode of bowel incontinence on course and finished the race.
The internet treated it as a scandal. Almost nobody printed the research, which says something calmer: bowel-control symptoms are common in people who train hard, most of what gets counted is gas, and sports medicine has a way of working through it. This piece is about athletes as a group, not one person, and it does not guess at the cause of anything that happened in Beijing.
The ruleWhat changed, and what was said
Before the change, the rulebook penalized littering, spitting and clearing your nose onto the floor, and said nothing about bodily fluids, Sixth Tone and 1News reported. The new clause says “may,” not “must,” and frames a withdrawal as a medical decision, not a disqualification. Hyrox co-founder Moritz Fürste said in a statement carried by AFP: “I apologise to all that were directly or indirectly affected, as well as to everyone who felt like we did not handle the situation like we should have.” Hyrox also offered full refunds to athletes whose races ran between 2:40 and 8:40 p.m. that day, Sixth Tone reported.
On September 18 the winner posted a public apology. She said she “felt completely fit and healthy at the start of the race, with no reason to expect any illness,” and she retroactively withdrew and forfeited the points she had earned, 1News reported. Her coach, in a statement reported by Newsweek, drew the line much of the internet missed: “Discussion is legitimate. The hatred and personal attacks that have followed are not.” That is where this article stops talking about Beijing.
The numbersHow common this is in people who train hard
Start in France. In 2011, gastroenterologists in Marseille surveyed 393 healthy women aged 18 to 40. Among the 169 who did high-level sport, more than eight hours a week, 14.8 percent reported anal incontinence, against 4.9 percent of the other 224. After adjusting for age and births, intensive sport roughly tripled the odds (odds ratio 2.99), even though the athletes were younger and had had fewer children. And the detail that matters most: in the athletes, 84 percent of it was loss of gas.
Other surveys land in the same place. In Australia, a 2021 survey of 1,379 women found anal incontinence symptoms in 34.0 percent of runners and 27.7 percent of CrossFit athletes, so the lifting-and-jumping group reported fewer symptoms than the runners. At the Santiago Marathon in Chile, a 2026 on-site survey of 366 women (no conflicts declared) found fecal incontinence in 7.1 percent, and race distance made no difference.
For men, the research is thin. A 2026 scoping review from the University of Canberra (no competing interests declared) found just ten studies of pelvic-floor problems in male athletes, and only one asked about bowel control. That one, a 2022 Norwegian survey of national-level powerlifters and Olympic weightlifters, found anal incontinence in 61.8 percent of 204 men and 80.0 percent of 180 women; in the authors’ conference report, accidental loss of gas was the most commonly reported type. Only 38 percent of the men invited replied, so the figure probably leans toward those with something to report.
| Study | Who | How many | What they found |
|---|---|---|---|
| Vitton, France, 2011 | Women 18–40, high-level sport (8+ hours a week) vs everyone else | 393 | Anal incontinence 14.8% vs 4.9%; in the athletes, 84% of it was gas |
| Forner, Australia, 2021 | Women runners vs women doing CrossFit | 1,379 | Anal incontinence symptoms 34.0% of runners, 27.7% of CrossFit athletes |
| Nalda, Chile, 2026 | Women surveyed at the Santiago Marathon | 366 | Fecal incontinence 7.1%; race distance made no difference |
| Skaug, Norway, 2022 | National-level powerlifters and Olympic weightlifters | 180 women, 204 men | Anal incontinence 80.0% of women, 61.8% of men; accidental loss of gas the most common type |
Among women training more than eight hours a week, 84 percent of what the study counted as anal incontinence was gas.
That is the part the pile-on skipped. Gas is what most of these numbers are made of, and gas is a normal product of digestion, as our explainer on farting sets out; what a hard effort adds is pressure. The subject is quiet in the literature too: a 2021 review of how pelvic-floor symptoms affect women’s exercise found no quantitative studies of anal incontinence at all.
The raceWhy a hybrid race is its own kind of load
A Hyrox race, per the rulebook, is eight 1-kilometer runs, each followed by a station: SkiErg, sled push, sled pull, burpee broad jumps, rowing, a farmers carry, sandbag lunges and 100 wall balls. In the women’s pro division the push sled weighs 152 kilograms, sled included. What its authors called the first scientific study of the format, a 2025 simulation with 11 recreational athletes in Munich (no commercial ties declared), found a median finish of 86.5 minutes, a median 79.5 percent of it at 90 to 100 percent of maximum heart rate. Heart rate, blood lactate and perceived effort all peaked at the last station, the wall balls.
That is shorter than a marathon but harder; our marathon piece covers what sustained effort does to blood flow to the gut. What a hybrid race adds is abdominal pressure. In a 2018 Texas study, ten women wore a pressure sensor through 13 CrossFit exercises, burpees and wall balls among them. The highest pressures came in double-unders, push-ups, front squats and wall balls; in double-unders, every participant averaged above 200 centimeters of water, against a published median of 91 for a cough. In a 2026 Norwegian lab study of 11 people, a deliberate pelvic-floor squeeze did not outpace the rise in abdominal pressure during squats, deadlifts, leg presses or curl-ups (two authors hold shares in the sensor’s maker). The counterweight: after 47 strength-trained women did an hour of heavy squats and deadlifts, their pelvic-floor muscle measures changed no more than after an hour of sitting.
Then there is what goes in before the start. In a 2025 double-blind crossover of 30 men and women doing a high-intensity workout that included wall balls and burpees (no conflicts declared), the highest dose of sodium bicarbonate, a buffer some athletes take before hard efforts, caused more total gut upset than placebo and did nothing measurable for wall-ball or burpee performance. Caffeine gets the colon moving, as we have covered. And we found no published study of gut symptoms in Hyrox racers: a health study of Hyrox athletes published by the University of Bath in September (89 athletes, 12 weeks, no conflicts declared), found a health problem in 30 percent of athletes in any given week but did not break out the gut.
The playbookWhat sports medicine describes
Sports medicine treats this as a problem to assess, not a character flaw. A 2026 practitioner’s guide from Monash University lays out four phases: a clinical assessment, a gut assessment during exercise, targeted strategies, then monitoring in real training. (The lead author runs a Monash clinic that offers gut assessments to athletes and is an editor of the journal that published it.) The two strategies with controlled trials behind them, training the gut on race fuel and a low-FODMAP race week, are in our marathon piece with their numbers, alongside the pre-race fiber cuts that are standard practice without firm evidence.
For the pelvic floor, the tool is physiotherapy. In a 2024 randomized trial of 47 women who do functional fitness (no conflicts declared), 16 weeks of home pelvic-floor training left 64 percent reporting improved stress urinary incontinence, against 8 percent of controls; anal-incontinence symptoms did not change significantly, a reminder that the bowel side is less studied. For bowel control in general, the National Institute of Diabetes and Digestive and Kidney Diseases says simple treatments, pelvic-floor exercises among them, “can improve symptoms by about 60 percent,” and that biofeedback, a guided version, “can be more effective than learning pelvic floor exercises on your own.” A Cochrane review is more cautious, calling the trials too limited for firm conclusions. The bigger gap may be knowledge: 72.5 percent of the Norwegian men and 44.4 percent of the women said they did not know how to train the pelvic floor.
NextBoston, and what a rule cannot do
HWPO HYROX Boston runs October 8 to 11 at the Boston Convention and Exhibition Center, the next race on the US calendar, with Tampa to follow on October 22 to 25. The clause gives race directors a medical option. It cannot change what bodies do under maximal effort, and the research says that what they do is common, mostly gas, and routine work for physiotherapists and sports dietitians. If symptoms show up in training, that is worth raising with a clinician or a pelvic-floor physiotherapist. This article is educational, describes what the cited rulebook, reports and studies say, and is not medical advice.