Sometimes people in recovery actually replace their substance of choice with exercising to the dangerous extent you mention - a different way of getting a fix.

Now I know about it too. How sad. We create beauty but cause such damage.

Bollocks. 'Chav' does not automatically equal 'poor', and nor is the sneering limited to the middle class.

He says his name's William but I'm sure,
He's Bill or Billy or Mac or Buddy
And he's plain ugly to me
And I wonder if he's ever had a day of fun in his whole life