Those hoping to avoid one of the worst side effects of aging—bone, joint and muscle pain that doesn't go away—might need to exercise a lot harder and more often than previously believed. According to a new study, only high levels of activity at least once a week—playing tennis, running, swimming, digging with a spade, or doing hard physical labor as part of your job—appears to help ward off chronic musculoskeletal pain in the long-term. The study is the first to examine the experience of chronic pain alongside gender, BMI, age and wealth over a long time period. Report co-author Dr....