Well, considering Lemmy's lifestyle and habits he does pretty damn well. I certainly wouldn't do most of the things he does, but then I've never had the fun he's had. Good on ya, Uncle Lemmy.
Once I saw an interview in which Lemmy said he didn't like exercise or sport, so I rate he ain't much of a bodybuilder but I think he's just to hardcore to wind up unfit. Rock keeps ya young.