After college, after Trump mostly gave up his personal athletic interests, he came to view time spent playing sports as time wasted. Trump believed the human body was like a battery, with a finite amount of energy, which exercise only depleted. So he didn’t work out. When he learned that John O’Donnell, one of his top casino executives, was training for an Ironman triathlon, he admonished him, “You are going to die young because of this.”