Whether you’re 9 or 90, abundant evidence shows exercise can enhance your health and well-being. But for many people, sedentary pastimes, such as watching TV, surfing the Internet, or playing computer and video games, have replaced more active pursuits. What exercise can do for you Millions of Americans simply aren’t moving enough to meet the minimum threshold for good health — that is, burning at least 700 to 1,000 calories a week through physical pursuits. The benefits of exercise may sound too good to be true, but decades of solid science confirm that exercise improves health and can extend your life. Adding as little as half an hour of moderately intense physical activity to your day can help you avoid a host of serious ailments, including heart disease, diabetes, depression, and several types of cancer, particularly breast and colon cancers. Regular exercise can also help you sleep better, reduce stress, control your weight, brighten your mood, sharpen your mental functioning, and improve your sex life.