What to Know About Rhabdomyolysis, the Condition Linked to a Marathon Runner's Death

On Nov. 1, a seemingly healthy 24-year-old woman from Pennsylvania, Rachel Apa, collapsed near the end of the New York City Marathon. She died later that day despite treatment, and her father told the New York Times that her death was linked to rhabdomyolysis, a condition in which damaged muscle tissue releases substances into the bloodstream that can injure the kidneys and sometimes the heart. Extreme exercise is one possible trigger. The city's medical examiner was still investigating the cause.

Rhabdomyolysis is a process where the muscle cells break down and die, says Dr. Douglas Farrell, a nephrologist at Mount Sinai Hospital in New York City. “By doing so, they release their contents, which can be quite toxic to the body and to the kidney.”

When exercise is the trigger, the condition is called exercise-induced rhabdomyolysis. Farrell's hospital is close to the finish line of the New York City Marathon, and he says he has seen a substantial number of cases over the years. In April, he and colleagues published a paper looking into a worrying trend: 24 people who ran in the 2022 New York City Marathon had rhabdomyolysis treated at nearby hospitals, while only 15 people in the previous five years combined sought help there for the condition after the race.

"I was a nephrologist on call during this time, and I saw a lot of patients. And I said, 'Man, this feels way more than what I remember,'" he says.

Temperature is a big one, says Farrell. When you exercise, your body needs to shed heat fast. When it's hot and humid, the body might not be able to cool down quickly enough to avoid the muscle damage that could lead to rhabdomyolysis.

Another factor is sudden temperature shifts. Slow temperature changes the body can handle: “If you are going to go somewhere that's hotter or more humid than what you're used to, your body needs about a week or two actually to acclimate,” he says. But big jumps are harder. He and his colleagues suspect this contributed to the large number of cases in 2022, which was the hottest and most humid year since the marathon moved to November in 1986. Among the years he studied, “2022 was also the only marathon in which it was much hotter the day of the marathon than the previous two weeks,” he says.

However, most people who run marathons, no matter the temperature, don't get this condition. “It is difficult to predict who will develop exercise-induced rhabdomyolysis before a race,” says Dr. Marie Vangstad of Oslo University Hospital in Norway, who has studied the condition. “The most important risk factor is unusually strenuous or unaccustomed exercise, particularly a sudden increase in training intensity or volume. Even well-trained athletes can develop rhabdomyolysis under extreme physical exertion. Some individuals also have underlying genetic conditions that increase their susceptibility, but many cases occur in people without any known predisposition.”

Deaths from exercise-induced rhabdomyolysis are exceedingly rare, Vangstad and Farrell agree. None of the patients from Farrell's paper on the 2022 marathon died. Treatment centers on fluids and monitoring kidney function and electrolytes. When heatstroke accompanies the condition, doctors try to rapidly cool the body down, often with ice baths. In more extreme cases, dialysis is used to manage kidney failure.