How many people benefitting from more exercise are elite endurance athletes?
https://openheart.bmj.com/content/9/2/e002154
> Conclusion: Although older male endurance athletes experienced an increased risk of AF, the long-term risk of stroke was substantially reduced compared with non-athletes.
Higher probability with zero exercise, lowest probability at moderate exercise, but an increase in probability as you enter the extreme territory. In my case, 1000+ hours/year for 8 years led to this outcome