Doing weight-bearing and strengthening exercises throughout your life can help you prevent osteoporosis. They help you build strong bones as a young person. And they help you maintain your bone thickness (density) as an adult. But if you stop exercising, your bones will start to thin.

Weight-bearing exercise includes aerobic activities such as walking, jogging, stair climbing, and dancing. Strengthening exercises involve resistance, such as lifting weights or using elastic bands.

Starting these exercises at any age will help prevent bone loss. It's best to do aerobic exercises for at least 2½ hours a week. For example, do them 30 minutes a day, at least 5 days a week. Experts recommend that you do resistance exercises at least 2 days a week.

Exercises that aren't weight-bearing, such as swimming, are good for your general health. But they don't work your muscles and bones against gravity or resistance, so they don't stimulate new bone growth.