Sprinting/interval training or any HIIT is great for cardiovascular health and fat loss while maintaining muscle mass, in my experience. And this is when on or off the sauce. It is, however, not necessary to shed fat-- although it does accelerate the process. To each his own, I like nelson montana's thoughts/theories based on his posts, but I have to somewhat disagree on this issue. As for heart enlargement, I don't know.
I respect him for his knowledge and honesty, and I want to buy his book since his opinions seem unique compared to most bb'ing writers/philosophies, but I don't want to be duped into spending 40 bucks on a bunch of redundant material. Time to use the search engine to see if I can find out more about it.
Peace.