Comment by proee

I don't know if this is true, but my cardiologist said that everyone who trains hard for a marathon has some level of heart damage from the excessive training. This sounds extreme to me, but I was in to see him for some AFIB episodes that were triggered from pushing myself too hard. It's worth noting that endurance athletes are 2 to 10 times more likely to develop AFIB compared to non-athletes. So this is a bit of warning to apply some level of moderation to your training.