Do this 10 times a day

Strong bones are key to healthy aging. But after age 30, it’s tough to increase bone mass. Jumping can help, says Dr. Roizen. He points to a study that found that women who jumped 10 to 20 times twice a day increased their bone density after 8 weeks; those who didn’t jump lost density. Knee issues? Jumping on a small trampoline brings the same benefits but is easy on the joints.