hopkins has the physical well being and health of a man who is 6/7 years his junior.
he looks after himself outside the ring and inside the ring. inside the ring he doesn't take alot of punches, he has a good chin but doesn't exploit it.
not only that but nazim richardson has always said that hopkins is a gym rat and loves being in the gym, this means that hes always in somewhat decent shape. add to that the high level of discipline he has with his diet (i.e. no alcohol, or junk food, no meat or swine) and its hardly a surprise that hes in such great condition.