Originally Posted by
alexaschwanden
You can do as much as you want, i am doing 400-500 miles a week and feel great.
It all depends on the intensity. If you are doing 400 miles a week in Zone 5, you are a prime candidate for Afib.
If you are doing 400 miles a week with about 5-10% of time in Zone 4-5, and rest in Zone 3, you are probably fine.
As I age, I have shifted my exercise mostly to Zone 3 with occasional forays into Zone 4 & 5.