Some studies have shown that running can cause leg and knee joints to deteriorate, causing osteoarthritis and often leading to joint replacement surgery. However, a paper published in a recent issue of Current Opinions in Orthopedics shows that an athlete's rigorous, high-impact, high-stress running regimen causes greater risk of severe joint deterioration. But baby boomers who take up recreational jogging probably aren't causing themselves any serious damage.
"Running two or three times a week is fine," lead author Nancy Lane, MD, tells WebMD. "But we also have to look at lifetime exposure. Over time, it could do some damage." Lane advises jogging at a moderate pace -- an 8-minute mile.
How osteoarthritis develops is unclear, says Lane, who is an associate professor of medicine at the University of California, San Francisco. However, damage to the bone surface can start a biological process that results in joint degeneration. Some exercise is believed to be beneficial to the joint because it increases the circulation of fluid that bathes the joint cartilage and helps keep cartilage and muscles healthy.
In the paper, the authors cite a recent study in which older women -- with an average age of 66 -- were followed for nine years. Some were runners, who averaged 41 hours of running a week; others were non-runners who exercised about two hours a week. While the runners decreased their running minutes by nearly 50% during the nine-year period, their overall weekly exercise minutes remained about the same.
There was evidence of knee damage in all the women, says Lane, "but it appeared that those who were active a few times a week in their teen-age and early adult years had a modestly increased risk of arthritis of the hip." This study shows that as individuals age, knee and hip osteoarthritis develops at a similar pace for both runners and non-runners, she adds.
"Overall, this study demonstrates that in normal knee and hip joints, regular recreational running does not increase development of osteoarthritis," says Lane. "However, to put this into perspective, these individuals started running in their 40s, and the exercise was low impact or recreational in nature."