I believe you do have to take a break, and people make a good point of exercising. Mind and body is one in the same. I know the hardcore Starcraft players in Korea, who get treated like rockstars apparently, take good care of their bodies. As for me, I'm lazy. I don't take care of myself. I don't multi table a lot so a few games of play, and the day is already over for me. Poker is screwing me over until I develop a better lifestyle >.<