(2004-03-29) Shaw Exercise

Jonathon Shaw on Exercise for Physical Fitness. Frank Hu believes that in discussions of the benefits of exercise, the extreme low end of the spectrum - sedentary behavior - is too often neglected. Being sedentary is an independent risk factor for coronary heart disease (CHD), notes Jo Ann Manson, even among people who do exercise. "We found in the Womens Health Initiative (a study of more than 160,000 postmenopausal women aged 50 to 79) that the longer you sit each day, the greater your risk of cardiovascular disease, even after you adjust for time spent in recreational activity." She tells her patients to get up and walk around as much as possible, and to reduce screen time (TV, video games, working at the computer). "The key is to minimize sitting," she says. Hu agrees. Given that the average American spends 4 to 5 hours a day watching television, he says, "For most people, it is not sufficient to address only the exercise side of the coin. Equally important is the sedentary side of the coin.".. And the optimal amount of exercise? Early studies suggested that when you reached a certain amount of activity, your benefit would plateau. "Our data so far don't support this assumption or hypothesis," says Hu. "Basically, the more the better. There is a straight dose-response relationship in both men and women. For preventing heart disease and stroke," he says, "there is no limit to the benefits of exercise." Is that benefit net of the risk of boring yourself to death?