Doctors have long known that diet and exercise are the best ways to stay healthy, but few people get enough exercise. Only a fifth of Americans get the recommended 150 minutes of strength and cardiovascular activity per week and more than 80 million Americans over age 6 are entirely inactive. It doesn’t help that many U.S. school have cut gym classes. Nearly half of high school students don’t have a weekly PE class while only a quarter of elementary school require PE at least three days a week. People leading an inactive life pay a price. They are at higher risk of serious health problems, including heart disease and cancer. Health experts want to raise awareness of the benefits of experience. They belive it can lead to slower aging, longer life, better mood, stronger vision – the list goes on.The U.S. National Institutes of Health (NIH) is playing a key role in the effort. This year, it is launching a mayor study which will record in detail with happens inside a body in motion. Through its research, the NIH hopes to prove scientifically taht exercise is good medicine. Studies show taht many positive changes occur in the body during and after a workout. Exercise restores muscles that have become weak, and can help repair tissues taht arefailing due to lack of use disease or injuries, or aging. One of the best pieces of news is that much of what we already do counts as physical activity. “Mowing the grass, raking leaves, washing the car-all that is exercise,” says Jack Berryman, a retired professor of medical history at Washington University School of Medicine, if Seattle. “Physical activity includes all movement, not just throwing a ball through a basket.” Berryman hopes the NIH study will give doctorsthe ability to provide patients with a detailed, individual workout plan. In the meantime,here is a prescription for good health: Get active!