Running the Risk, What We Need to Know About Cardiac Arrests During Marathons
- Mar 31
- 4 min read
Updated: Apr 1
A new study published in JAMA has shed light on a concern that lingers in the minds of many endurance runners: the risk of cardiac arrest during long-distance races. While the overall incidence of cardiac arrests during US marathons and half-marathons has remained largely stable since 2010, the chance of surviving such an event has dramatically improved - more than doubling over the last 15 years. Our home base of Singapore also has an incredibly popular annual marathon - the Standard Chartered Singapore Marathon - that has also dealt with cardiac arrests during the event.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies at bottom of page.
What the Numbers Reveal
Between 2010 and 2023, over 29 million people completed marathon or half-marathon races in the US. Among these runners, 176 cardiac arrests were recorded - roughly one for every 167,000 finishers. However, the rate of death from these events was halved compared to the previous decade. To put that into perspective, the fatality rate dropped from approximately 0.39 to 0.20 per 100,000 runners, a decline of nearly 50%.
Survival after cardiac arrest rose from 29% in the early 2000s to 66% in the 2010s and early 2020s. This improvement is largely attributed to better race-day emergency protocols - specifically, faster access to CPR and defibrillators.
Who’s Most at Risk?
Men remain more likely to suffer a cardiac arrest during these races than women, with male runners accounting for over 70% of all cases. The risk was also higher in marathon runners than in those running half-marathons. For men competing in marathons, the rate was about 1.8 cases per 100,000 participants - roughly double the overall average.
Age also matters. Interestingly, those who survived were on average older than those who did not - suggesting that younger runners experiencing cardiac arrest may be more likely to have undetected heart abnormalities or congenital conditions.
A Shift in Cause: From Genetic to Lifestyle-Linked
Earlier studies had pointed to hypertrophic cardiomyopathy (a genetic heart condition) as a leading cause of cardiac arrest in runners. However, this new analysis found that coronary artery disease - a condition tied to cholesterol build-up and often lifestyle-related - was now the most common culprit.
In fact, coronary artery disease accounted for 40% of cases where a cause was known, and nearly all of those affected survived, likely thanks to rapid emergency care. Only a small percentage of cases were attributed to hypertrophic cardiomyopathy or heat stroke.
One concerning detail: four of the fatalities showed traces of stimulants such as caffeine, amphetamines or pseudoephedrine in their systems. While the significance isn’t yet clear, it’s a reminder to be cautious about energy drinks or medications before racing.
Why Survival Has Improved
The biggest change in the past decade has been the quality and speed of medical response. All runners with complete clinical profiles received bystander CPR, and the vast majority had access to an automated external defibrillator (AED). In contrast, from 2000 to 2009, only about half received prompt CPR or defibrillation.
This level of emergency preparedness - now standard at many races - has brought race-day survival rates in line with those seen in airports and schools, where AEDs are readily available.
The COVID-19 Effect?
Cardiac arrests rose slightly between 2020 and 2023, and while the study didn’t find any direct links to COVID-related heart conditions like myocarditis, the authors speculate that reduced access to routine healthcare during the pandemic may have played a role. Undiagnosed or untreated heart disease could have made some runners more vulnerable.
Final Thoughts
For most runners, the takeaway from this study is reassuring: running marathons and half-marathons remains a low-risk activity when it comes to cardiac events. However, if you're a middle-aged man training for a marathon - or if you have a family history of heart disease - it’s worth having a heart health check before race day.
What’s equally clear is that lives are being saved thanks to better preparation. From on-site medical teams to strategically placed AEDs, the infrastructure around races has made long-distance running not just more popular but safer. And with continued emphasis on cardiac screening and emergency readiness, that trend is likely to continue. And let's not forget why many of us are running - to improve our health and get more enjoyment from life!
For most people, improving health is about finding motivation and prioritising self-care - with an ultimate goal of taking action. If you want to take effective and targeted steps that fit into your unique lifestyle, The Whole Health Practice is here to help. Whether your interest is healthspan and longevity, to beat chronic illness or to enhance your mental health and well-being, our consultations and programs deliver results that are tailored to your needs.
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Stay Healthy,
Alastair
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Related Studies
The study in review... Kim JH, Rim AJ, Miller JT, et al. Cardiac Arrest During Long-Distance Running Races. JAMA. Published online March 30, 2025. doi:10.1001/jama.2025.3026
Other
Waite O, Smith A, Madge L, Spring H, Noret N. Sudden cardiac death in marathons: a systematic review. Phys Sportsmed. 2016;44(1):79-84. doi: 10.1080/00913847.2016.1135036. Epub 2016 Jan 14. PMID: 26765272.
Manabe T, Kato J, Yamasawa F. Sudden cardiac arrest during marathons among young, middle-aged, and senior runners. Resuscitation. 2024 Nov;204:110415. doi: 10.1016/j.resuscitation.2024.110415. Epub 2024 Oct 20. PMID: 39437933.
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