The majority of physically active participants exercised between 355 and 2,119 minutes per week over the course of the study, while controls exercised significantly less.

Those who engage in a regular program of an aerobic exercise such as running, for example, have less pain than non-runners. But there is a downside -- they are also more likely to experience pain from injuries.

Pain Increased in Both Groups over Time

Bonnie Bruce and colleagues from Stanford University compared the level of pain reported by a group of runners compared to a control group. The participants -- 492 Runners' Association members and 374 controls -- were in their mid-sixties, on average, when the 14-year study began.

Each year, they completed a questionnaire about their health status, exercise habits and history of injuries.

The majority of physically active participants exercised between 355 and 2,119 minutes per week over the course of the study, while controls exercised significantly less.

The researchers adjusted for confounding such factors as gender, age, weight and health status. Pain increased in both groups over time, the results indicate. But members of the Runners' Association experienced 25% less musculoskeletal pain than controls -- a reduction that persisted throughout the study period, until the subjects reached an age of 62 to 76 years.

Significant Reduction in Pain

"Exercise was associated with a substantial and significant reduction in pain," the authors note, "despite the fact that fractures, a significant predictor of pain, were slightly more common among runners."

More research is needed to investigate the mechanisms that might underlie the effect of exercise on musculoskeletal pain in old age, they conclude.