Seriously? We created a race modeled after a guy that DIED doing it???
Anyway, I've wondered about chronic cardio and marathon-type stress for years. I remember hearing that you should work muscles every other day (so something like upper body MonWedFri and lower body TueThuSat), but then they always said cardio should be every day. But isn't the heart muscle too?
Definitely not a scientist, but that always bothered me.