Lifting weights three times during the week can work many wonders for your body. It will help increase your bone density, which helps prevent osteoporosis. Over time your muscles, tendons and ligaments will get stronger, reducing your risk of injury from sports or everyday activities. Plus, after the age of 30 we start to lose about one-half pound of muscle per year, which can cause your metabolism to slow down. Weight lifting increases your lean muscle mass, making it a little easier to maintain your weight. And, of course, as you get stronger, everyday activities will be more tolerable.