I'm really not sure if performance enhancing substances would have anything to do with it. I am the farthest from what anyone would call a doctor, but here in the United States, we see players who were found guilty of using performance enhancing substances severly affect them after their playing days are over, not so much while they are still in the midst of their playing careers
I'm not sure. I do know that a lot of footballers get enlarged hearts due to the amount of running they do. But clubs don't really monitor those things.
