Abstract Sun608: Sex Differences in Sudden Cardiac Arrest During Endurance Races: Could Acceleration Variability Account for the Disparity?

Background: Men account for over 85% of Sudden Cardiac Arrest (SCA) occurring during sport activities. This over-representation persists even after adjusting for sports participation and cannot be fully explained by biological or physiological factors. We hypothesized that male psychology and related behavioral responses might play a role in this over-representation. Method: We integrated data from two independent sources. The first was a cardiac arrest registry that prospectively and extensively collected data on 55,000 out-of-hospital cardiac arrest in individuals over 18 years old within a given area between October 2011 and April 2024. The second source contained race participation records for half-marathon (HM) and 20 km race from 2011 to 2024. Data were collected annually (excluding 2020 due to the pandemic) before being aggregated. This study focused exclusively on race finishers and SCA cases. Acceleration was calculated by comparing the speed over the last kilometer with the average speed over the previous five kilometers, with each runner serving as their own control. Acceleration was categorized into 0.2 km/h intervals, and we analyzed the distribution of male and female runners within these categories. To estimate the 95% confidence interval (CI) for the male-to-female ratio in each acceleration category, we used the log-ratio method. Results: Over the past 10 years, among 714,856 participants (68.2% of males), 12 cases of SCA were recorded. Of these, 83.3% (10/12) were men, with a mean age of 39.7 ± 10.7 years. Notably, 9 out of 12 SCAs occurred in the final kilometer of the race. An acceleration in speed was observed in 87% of finishers during this last kilometer. The proportion of men who accelerated within 0 and 1 km/h (mild) was lower than that of women (0.87 [95%CI 0.86-0.87], p<0.001). Conversely, the proportion of men who accelerated by more than 2 km/h (strong) was nearly twice that of women (1.96 [95%CI 1.86-2.06], p < 0.001) (Figure 1). Conclusion: While direct causality cannot be established, men’s competitive attitudes and behavioral responses may partially explain their over-representation in sport-related SCA.