When a 24-year-old runner collapsed near the finish line of the New York City Marathon and died, the story spread fast. Rachel Apa's death shook the running community, partly because of her age, partly because marathons are supposed to be a celebration of human endurance. But the cause of death wasn't a heart attack. It was rhabdomyolysis, a condition most recreational runners have never heard of, let alone trained around.
The headlines that followed blurred the distinction. "Marathon death" implies cardiac arrest to most readers. The reality is more complicated, and understanding it matters if you're training for a 26.2 or thinking about your first.
What Rachel Apa's Death Actually Tells Us
Rhabdomyolysis, often called "rhabdo," occurs when muscle fibers break down rapidly and release proteins into the bloodstream. The kidneys can't filter the volume fast enough, leading to acute kidney injury and, in severe cases, organ failure and death. It's not exclusive to marathons. It can happen in CrossFit gyms, military training, and endurance cycling. But marathon conditions can create a perfect storm for it.
Heat, dehydration, and extreme physical exertion are the three primary triggers. When you combine a high ambient temperature race day, a runner who may have pushed beyond their current fitness level, and the psychological pull of a finish line, the risk compounds. Apa was 24 and apparently healthy. That's part of what makes rhabdo so unsettling: it doesn't require a pre-existing heart condition to kill.
What her death is not, according to medical experts who reviewed the case publicly, is evidence that marathons are becoming more dangerous overall. The data points in a different direction.
The Cardiac Risk Picture, By the Numbers
Studies tracking cardiac arrest rates at mass-participation marathons consistently put the risk of sudden cardiac death between 0.5 and 2 per 100,000 finishers. The most cited figure from large-scale US marathon data sits around 1 per 100,000. For context, that's lower than the risk of cardiac death during recreational jogging in the general population across a full year.
More importantly, that rate has been falling. Improved on-course defibrillation coverage, faster medical response protocols, and better pre-race cardiac screening have all contributed. At events like the NYC Marathon 2026, which broke finisher records with more than 60,000 finishers crossing the line, the medical infrastructure has scaled to match. Survival rates for cardiac arrest at major marathons now exceed 50% in many events, compared to under 10% for out-of-hospital cardiac arrest in the general population.
So if you're worried about your heart on race day, the evidence says the sport has gotten meaningfully safer, not more dangerous.
The Post-Pandemic Complication
Here's where the picture gets more nuanced. While cardiac death rates have held steady or improved, non-fatal cardiac events have shown a slight uptick since 2020. The likely explanation isn't medical. It's demographic.
The post-pandemic running boom brought a wave of first-time and undertrained participants to race start lines. Races like the Nice-Cannes Marathon 2026, which set a record with 25,000 runners, reflect a global surge in participation. More participants is good for the sport. But if a meaningful percentage of those participants are undertrained, the risk profile of the field changes.
Research published in sports cardiology journals has consistently shown that the cardiac risk in marathon running is concentrated in a few groups: men over 40, participants with undiagnosed structural heart abnormalities, and those who haven't properly built aerobic base. When participation spikes rapidly, those risk categories don't disappear. They multiply across a larger field.
The takeaway isn't that marathons are dangerous. It's that your preparation matters far more than the race itself.
Rhabdomyolysis: The Risk You're Not Training For
Cardiac events get the coverage. Rhabdo largely doesn't, which is part of why Apa's death was so disorienting for the running community. But the risk factors are well established, and most of them are addressable before you ever reach a start line.
- Heat and humidity. Rhabdo risk rises significantly in warm conditions. Race-day temperature above 72°F (22°C) is associated with higher rates of heat-related illness across marathon fields. If you're training in a cool climate and racing in a hot one, your body isn't adapted.
- Dehydration. Inadequate fluid intake concentrates the muscle proteins released during breakdown. Electrolyte imbalance compounds the problem. This isn't about drinking too little water on race day. It's about hydration strategy across your entire training block.
- Sudden mileage spikes. Rhabdo occurs when muscles are worked beyond their current capacity. If you've jumped from 20 miles per week to marathon training in a compressed window, your musculoskeletal system hasn't had time to adapt.
- Inadequate base training. Running 26.2 miles on a base better suited to a half marathon doesn't just slow you down. It stresses your muscles in ways that can tip into dangerous territory, particularly in hot conditions.
The article "How Hard Should You Actually Train at the Gym?" covers the broader principles of load management that apply directly here. The core concept is progressive overload with recovery built in, not just adding miles until something breaks.
What Smart Preparation Actually Looks Like
The gap between "finishing a marathon" and "finishing a marathon safely" is mostly filled by training time and honesty about your current fitness level. Here's what the evidence supports.
First, don't compress your base. Most sports medicine guidelines recommend at least 16 to 20 weeks of structured training before a marathon, starting from a base of 25 to 30 miles per week. If you're nowhere near that base when you sign up, consider a half marathon this cycle and build properly for the full.
Second, heat-acclimate intentionally if you're racing in warmer conditions than you train in. Research shows the cardiovascular and thermoregulatory adaptations from heat training take 10 to 14 days of consistent exposure to develop. That's time worth investing.
Third, treat fueling and hydration as skills, not afterthoughts. Rhabdo and heat illness are both worsened by going into a race underfueled and underhydrated. Practice your race-day nutrition strategy in long training runs. Know how much you sweat per hour. Dial in your electrolyte intake. If you're using caffeine as a performance tool, understand the dosing. The relationship between caffeine, exercise, and cardiac risk is worth understanding before you're four gels deep at mile 20.
Fourth, don't ignore warning signs during the race. Rhabdo doesn't always announce itself dramatically. Unusual muscle cramping, dark urine, extreme fatigue beyond expected effort, and nausea can all be early indicators. Slowing down or stopping is not failure. Getting to a medical tent when something feels wrong is the right call.
The Broader Risk Context
It's worth stepping back from marathon-specific data to understand where endurance racing sits in the larger landscape of exercise-related risk. Competitive endurance events, including triathlons, ultramarathons, and obstacle races, all carry some degree of risk that recreational exercise in a gym or on a bike trail does not. The intensities are higher, the durations are longer, and the environments are less controlled.
Events like HYROX, which carries its own joint stress risks, illustrate that the fitness community is increasingly drawn to high-output events that require specific preparation. The pattern across all of them is the same: the risk isn't the event. It's the mismatch between the demand of the event and the preparation of the participant.
Marathons are not uniquely dangerous. At roughly 1 cardiac death per 100,000 finishers, they're statistically safer than many activities people don't think twice about. But they do require honest preparation, and the sport's explosive growth post-pandemic has introduced a cohort of participants who may be crossing start lines before they're ready.
What You Should Take From This
Rachel Apa's death deserves to be understood accurately, not absorbed as a vague warning that marathons kill young, healthy people. Rhabdomyolysis at a marathon is rare. It is also largely preventable with the right training approach, heat preparation, and hydration habits. Cardiac death at marathons is rarer still, and declining.
The number that matters most isn't the death rate at race events. It's how well your training matches the demand you're about to place on your body. Build your base over time. Respect heat. Hydrate strategically. And be honest with yourself about whether you're ready for the distance you've signed up for.
That's not a reason to avoid marathons. It's a reason to take them seriously.