剛查了一下，是有統計數字（主要因為Cardiac arrests）。不過鐵人三項死亡率更高（有一位親戚以前很愛好過）：

“Out of 10.9 million marathon runners, the death rate is 1 per 259,000 participants, compared to 1 death per 52,630 participants in triathlons.”

https://www.runsociety.com/health-injuries/fit-runners-suddenly-die-while-running-marathons/

 

https://www.dailymail.co.uk/health/article-14647645/Marathon-runners-risk-death-experts-warn-alert.html