THE CLAIM -- Running increases the risk of osteoarthritis.
THE FACTS -- As any person who jogs regularly will tell you, a life of pounding the pavement can result in aching knees and joints. It is no surprise, then, that many runners worry about developing osteoarthritis, the degenerative joint disease. But in numerous studies over the years, researchers have found that people who jog moderately a few times a week are not especially susceptible to osteoarthritis. Compared with people who do not exercise at all, recreational runners are generally less likely to suffer from joint problems.
Experts say overworking a previously injured knee or joint can lead to more damage. Professional athletes often have higher rates of arthritis, for example, because of repeated injuries over years. But in healthy joints, moderate exercise strengthens bones and muscles; that is believed to help prevent osteoarthritis and other problems. Exercise also reduces excess weight, which can place stress on joints and increase the chance of developing arthritis.
In the 1980's, researchers at Stanford compared hundreds of runners to nonrunners over a five-year period. The runners, though they experienced aches and pains, had fewer joint or muscle problems than the control group. They spent about 33 percent less time in the hospital, had lower blood pressure and missed half as many workdays.
The researchers, however, could not rule out the possibility that people who were previously healthy were simply more likely to take up running. Years later, a study in The American Journal of Sports Medicine found that 30 long-distance runners who averaged more than 12 miles a week over four decades showed no difference in rates of arthritis in their hips, knees and ankles when compared with a group of nonrunners. Another study found that people who suffered joint injuries as young adults were almost twice as likely to develop osteoarthritis by the age of 65 as people without earlier injuries.
THE BOTTOM LINE -- Recreational running has not been shown to increase the risk of osteoarthritis. ANAHAD O'CONNOR
Drawing (Drawing by Jody Emery)