Paris race data covering 1.2 million+ participations shows sudden cardiac arrests are rare but disproportionately concentrated in the final kilometer especially in the 20 km and half marathon highlighting the “finishing surge” as a potential trigger and the value of rapid on-course response.
A decade of race data from Paris suggests the most dangerous stretch of an endurance event may not be the opening climb or the long grind in the middle, but the final kilometer.
A new analysis drawing on more than 1.2 million race participations between 2011 and 2024 examined sudden cardiac arrest cases during the Paris 20 km, the Paris Half Marathon, and the Paris Marathon.
Researchers combined registry data from the Paris Sudden Death Expertise Centre with official race results to identify adult cardiac arrests occurring on race day within a defined time window.
Across those events, 17 sudden cardiac arrests were recorded. The absolute risk remains low.
Incidence was 16.9 per million participations in men and 5.7 per million in women, with 15 of the 17 cases occurring in male runners. The average age was 42.
The striking pattern was location. In the 20 km race, 6 of 7 arrests occurred in the final kilometer. In the half marathon, 3 of 5 clustered in the same stretch. The risk of arrest in the final kilometer of the shorter races was more than 15 times higher than elsewhere on the course.
Researchers point to the final surge, where runners often accelerate sharply, as a potential trigger. Most half marathon finishers sped up at the end, with men nearly twice as likely as women to surge.
Survival outcomes were strong, with 88 percent discharged with good neurological status, underscoring the importance of rapid on-site response.
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