Being elected president forces a man to take inventory of his life, so Barack Obama has trimmed his schedule to the bare essentials. He's not in the White House yet, but gone are the hours he once spent reading novels, watching television and obsessing over the daily transactions of Chicago's sports teams. He eats out only once every few weeks. He visits friends rarely, if at all. But one habit endures: Obama has gone to the gym, for about 90 minutes a day, for at least 48 days in a row. He always has treated exercise less as recreation than requirement, but his devotion has intensified during the past few months. Between workouts during his Hawaii vacation this week, he was photographed looking like the paradigm of a new kind of presidential fitness, one geared less toward preventing heart attacks than winning swimsuit competitions. The sun glinted off chiseled pectorals sculpted during four weightlifting sessions each week, and a body toned by regular treadmill runs and basketball games. The more Obama's life intensifies, friends said, the more he relies on the gym -- which is why he might be taking office in the best shape of his life. The gym is where he releases stress, maintains a routine and thinks without interruption. He sometimes wears headphones and barricades the outside world. "He does it every day like clockwork," said Marty Nesbitt, one of Obama's closest friends from Chicago. "He doesn't think of it as something he has to do -- it's his time for himself, a chance for him to reflect. It's his break. He feels better and more revved up after he gets in his workout."