A marathon’s muscle damage can turn into a medical emergency
Rhabdomyolysis is rare, and death from it rarer still. But a runner’s death after the 2026 New York City Marathon shows why the condition deserves attention. Twenty-four-year-old Rachel Apa collapsed during the race and died in hospital after doctors spent six hours trying to save her, the New York Times reported. Her father told the newspaper that rhabdomyolysis, often shortened to rhabdo, caused her death.
The news has left runners asking how this could happen to a 24-year-old who reportedly played Division I field hockey at Bucknell and trained for months. Those details don’t tell us what happened in Apa’s case, and they shouldn’t be treated as an explanation. They do sharpen a broader question: what makes ordinary exercise related muscle damage dangerous enough to threaten the kidneys and heart? Doctors can help answer that, and explain what runners should watch for.
Rhabdo starts with muscle breakdown
About 26,000 rhabdomyolysis cases are reported in the U.S. each year. The reported death rate begins around 10 percent and can reach 50 percent in severe cases, though dying from rhabdo remains uncommon. The condition itself is muscle tissue breaking down; the danger comes when that breakdown overwhelms the body’s ability to handle what muscle cells release.
After a marathon, elevated creatine kinase (CK), a blood marker of muscle damage, would be common, says Derek M. Fine, a nephrologist at Johns Hopkins Medicine. Fine says “most” marathon runners would have elevated CK if tested after racing. That alone doesn’t establish rhabdo: the Centers for Disease Control and Prevention says repeated CK tests are needed for an accurate diagnosis. Typical levels run from 20 to 200 U/L; rhabdo is diagnosed at five times the upper limit.
Some muscle damage is part of strenuous exercise. Fine explains that during a marathon, muscles can use energy faster than their mitochondria can produce ATP, or adenosine triphosphate. The breakdown itself isn’t necessarily life threatening. The problem is what can follow when it becomes severe.
Why severe cases threaten the kidneys and heart
Damaged muscle can dump myoglobin and potassium into the bloodstream. Myoglobin may lodge in the kidneys and cause injury or failure, Fine says; that damage can take time to emerge. Potassium may pose a more immediate threat. A sudden surge can disrupt the heart’s electrical rhythm, and in extreme cases contribute to cardiac arrest.
Healthy kidneys usually remove excess potassium as it appears. With severe muscle breakdown, the release can outpace the body’s ability to clear it. Rhabdo can also produce complications that resemble sepsis or progress to multiple organ failure, Fine says.
Rhabdo isn’t a common underlying cause of cardiac arrest, says Lili Barouch, a sports cardiologist at Johns Hopkins Medicine and an endurance athlete. Still, severe electrolyte disturbances—especially high potassium—can trigger abnormal heart rhythms. Kidney or other organ failure can also create cardiac problems.
Hard efforts, heat and hydration all matter
Running isn’t the only exercise linked to exertional rhabdo. Any intense workout can damage muscle, Barouch says; Fine points to reported cases among CrossFit athletes. The risk can rise when someone pushes beyond what their training has prepared them for. Marathon race day often brings a much harder effort than routine training, Barouch says, and Fine identifies overexertion by an undertrained athlete as the most common setup. That’s a general risk factor, not an explanation of Apa’s death.
Dehydration can make it harder for the kidneys to clear muscle breakdown products, Barouch says. But simply drinking more isn’t a safe fix. During a marathon, the kidneys may be signaled to retain water; drinking too much can dilute blood sodium and cause hyponatremia. Fine’s practical guidance is to drink to thirst and take electrolytes during long or hot races. Adequate fluid intake may help clear myoglobin, but the balance matters.
Fuel may matter, too. Fine says inadequate carbohydrates can leave the body short of the energy it needs to make ATP, contributing to muscle breakdown. Heat is another concern: Fine calls a particularly hot race day a major risk factor. A study in Nephron Clinical Practice recorded 24 cases of exertional rhabdo at the 2022 New York City Marathon, likely linked to unusually high heat and humidity.
Fine says younger runners may face greater risk because they may be more likely to take chances, push harder and ignore warning signs. The fragment doesn’t establish how much age changes risk, but it does underline a practical point: toughness doesn’t protect a runner from the consequences of overexertion.
Personal history may be a clue
Rhabdo can have a genetic component, Fine says. Anyone who has had it before—or has a family member who has—may want to discuss their own risk with a clinician. Genetic tests can look for markers associated with susceptibility, but Fine doesn’t recommend routine prescreening before a marathon. Testing may make more sense for someone with a prior episode, such as rhabdo after CrossFit who now plans to take up distance racing.
