Although more people compete in marathons in the United States than ever before, the risk of dying from a heart attack during a run has dropped dramatically in recent years. This is an important conclusion from a new study by Jonathan Kim, associate professor at Emory Medical School. Kim’s study is a follow-up to a study he published in 2012, the first investigation into unexpected cardiac arrest in a long-distance running event.
New discoveries, published in Jama, show that although marathon runners suffering from cardiac arrest remained the same, their chances of survival were twice as fast as they did in the past. Now, fewer and fewer marathon athletes suffer from cardiac arrest.
“We continue to see media reports about unfortunate cardiac arrest cases in long-distance running events,” King said. “But did the incidence of these events change? Did the most common causes of cardiac arrest change? What are the factors related to death and survival? Asked 13 years after our first analysis, this is a new question, an important question, and an important question, as recreational running continues to increase popularity.”
The challenge of finding data
Between 2010 and 2023, more than 29 million people completed marathons in the United States, which was three times the number of Kim in his first study. There is no central registry for race-related cardiac events, so for both studies, his team had to find their data through a range of sources, starting with contacting individual race supervisors.
“We utilized some sources, including a comprehensive review of media reports,” King said. “We also provided contact information to all racial executives and were able to reach about 70% of them who helped us in this specific timetable and told us the number of activities, including individual deaths and the gender of the participants.”
Researchers used extensive public internet searches to identify and connect with runners of surviving cardiac arrest or close relatives to construct detailed profiles of as many cases as possible. “The vast majority of cases are determined by public search engines,” King said.
In analyzing this extensive database, Kim found that although the incidence of cardiac arrest is similar in both periods – now it is 0.60 per 100,000 participants, compared with 0.54 per 100,000 participants (per 100,000 participants) – the mortality rate for these cases is half but half: from every 100,000 billion to .19 to 0.19 per 100,000. Since 2000-2009, the mortality rate has dropped by about 50%. As before, cardiac arrest is more common in men than in women than in women, and more common in marathons than in half marathons.
The sport is increasingly aware of the risk of heart death
What causes a huge change in mortality? King believes that the sport has become increasingly aware of the risks of emergency services available to runners, which is the conclusion he came to after interviewing as many survivors as possible. “We found that each of these people had hands-on CPR, but the vast majority also had immediate access to automated external defibrillators,” he said. “That’s the difference.”
This survival rate is comparable to cardiac arrest survival in other public places that now make defibrillators routinely available, such as airports and casinos, where deaths decline similarly.
King said his findings provide additional evidence of how important it is to make CPR training available to race participants and strategically showcasers on race tracks. It is also important to better determine the most vulnerable people in the population to compete.
“These are often preventable events,” King said. Being able to identify people, more common older people with unidentified cardiovascular risk factors, does not mean they cannot compete. Instead, it provides opportunities for improving opportunities for major preventive cardiovascular care and potentially further reduces the risk of central arrest in these events. The incidence of long-term continuous competition has not changed over a period of 20 years. I think this is an important study.
Quote: “Cardous arrest in long-distance running competition.” Jama. March 30, 2025. doi:10.1001/jama.2025.3026.
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