UrbanUpdate

Chris Thornham had his training dialed in. He was working with a pro cycling coach and squeezing in 15 hours a week as he prepped for a 100-mile mountain bike race—nothing out of the ordinary for him. But mid-race, things started to go sideways. “I would reach for food and my bicep would cramp. My jaw, hands, my quads, basically every muscle in my body was cramping,” he says. As an endurance athlete, he was no stranger to pain, so he kept on pedaling. But after he crossed the finish line, he sat in the medical tent, shaking uncontrollably. Thornham suspected he might have rhabdomyolysis, a dangerous condition caused by muscle damage, but he wasn’t peeing brown (a tell-tale sign), so he went home. Two days later, still foggy and unable to think clearly, he told his wife, “I think you should take me to the hospital.” He was admitted for four days and pumped full of IV fluids to flush out his system.

What is Rhabdo?

Rhabdomyolysis, or rhabdo for short, is a medical condition that occurs when your muscles take too much damage, too fast. “This breakdown of muscle causes the intracellular contents of the muscles to leak into the bloodstream,” explains Tedd Girouard, director of the athletic training program at University of Nevada Las Vegas. These proteins and electrolytes, when released in large amounts, can overwhelm the kidneys, which “is made up of all these little tubes that filter blood and help us produce urine,” says Girouard, “If the tubes get blocked, the kidney can’t do its job anymore.” This can lead to swelling, increased body weight from water retention, and kidney failure.

The spectrum of rhabdo ranges from mild (think next-level soreness) to life-threatening. Girouard mentions that some athletes likely experience minor cases and recover with rest and hydration, while others develop flu-like symptoms or intense swelling post-working, indicating the condition is worsening. In extreme cases, rhabdo can be fatal. If you’re concerned, the only way to know for sure is to get a blood test for creatine kinase, a muscle protein. Girouard’s advice? if you're seeing concerning signs, don't take your chances—seek medical help immediately.

The Warning Signs

The first warning sign of rhabdo is pain that goes way beyond your normal workout soreness, says Alex Rothstein, program coordinator of exercise science at New York Institute of Technology. (In Thornham’s case, it was extreme cramping during his ride.) Another sign? A steep drop in performance. If a usually manageable workout suddenly feels impossible, it’s time to call it. Marathoners or endurance athletes, especially, should pay attention to this: “If you should be moving fast based on your training but now you’re walking and it’s very painful, that would be an early indicator,” says Girouard.

While urine is the hallmark symptom of rhabdo, it’s not always a good gauge. “By the time that you're starting to experience this with urine—whether you’re having little or very dark urine—it's a sign you've already gone too far,” says Rothstein. In Thornham’s case, he never experienced dark urine, which shows that rhabdo can present differently depending on the person.

Who’s at Risk?

While the condition is quite rare, rhabdo often makes headlines after grueling college sports practices or military training—like an incident at Tufts College that left 9 lacrosse players hospitalized. This is more likely when athletes jump into heavy training at the beginning of the season without enough preparation.

It is also commonly associated with high intensity interval training (HIIT) and group settings, like CrossFit, spin classes, or Navy SEAL training. “With the group mentality, there's a lot of peer pressure to exercise harder and harder,” says Girouard. So the very thing that makes group classes great—the motivation to push yourself—can also make them risky. This is something that both individuals and coaches should be mindful of: Just because the goal is to complete “as many reps as possible” (AMRAP, a popular CrossFit format) doesn’t mean you should push to the point of collapse.

But it can happen to anyone, in any type of activity, if they push beyond what they’re used to. Well-trained athletes also aren’t exempt. Environmental factors like heat or dehydration, as well as genetics, can make anyone more susceptible to rhabdo. The rise of ultra-endurance events, like Everesting, ultra-marathons, and multi-day adventure races, where the goal is to push your body to the absolute limit, only increases the danger, as these events are tough to properly train for. That doesn’t mean you should avoid these types of events or workouts, but it’s essential to stay aware of your limits and listen to your body.

Preventing Rhabdomyolysis

While rhabdo is dangerous, it’s rather preventable if you progressively overload both cardio activities and strength and conditioning. “If you’re training for a marathon, we don’t go from 5 miles to 26. You start out running a 5k, then 5 miles, then 7 miles, then 9, and so on,” says Girouard. “It’s the same thing with high-intensity interval training. You may start out doing 15 squats, 15 pull-ups, and 15 burpees. But tomorrow we don’t do 100 of each.” While our bodies may be physically capable of amazing feats of strength right off the couch, “the amount of damage and risk of injury that comes with it is quite significant,” he says.

The solution? Stress, rest, repeat. Give your body a workout, then give it time to recover before increasing the load. “The issue comes into play when somebody doesn’t prescribe to the progression. They’re a little too quick to jump in,” says Rothstein. “This isn’t the classic ‘hell week’ that every high school athlete did.”

And if you’re already well-trained, you should listen to your body and quit pushing too hard when something feels off. “If you get on a treadmill, you're warming up for your workout and you normally start to feel energized but today you feel worse, that’s a red flag,” says Rothstein. This type of fatigue—where you feel worse, not better with movement—is called central nervous system fatigue. It’s a pretty good day to dial it back or opt for active recovery.

Thornham learned the hard way by pushing through everything (so hopefully you don’t have to.) “Now if I have something on the schedule that is harder and I don’t feel good, I just go easy or go home,” he says. “Consistency is far more important than any individual effort.”

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Hannah Singleton is a freelance journalist who writes about fitness, health, wellness, and the environment. Her work has been featured in publications such as the New York Times, Wall Street Journal, GQ, Vox, Wired, National Geographic, Forbes, and Fast Company. She earned a master's degree in environmental studies from Prescott... Read moreRelated Stories for GQWorking OutHealth