Regardless of age, the condition of our bones is always changing - for better or for worse. Until about the age of 25 the news is generally good. Our bodies manufacture new bone tissue faster than old bone breaks down. After 30, we begin to lose more bone tissue than we gain. What can you do about it? Exercise to increase bone mass and strengthen it, but do so with physical activities that dont cause further damage. In order to strengthen bones, you need to put more load or impact on them than usual, says Maribeth Gibbon, PT, a physical therapist in the Department of Physical Medicine and Rehabilitation at Cleveland Clinic.