Exercise in Moderation Recommended to Avoid Bad Knees
Researchers at the University of California San Francisco report during a presentation at the Radiological Society of North America meeting that too much exercise results in early degenerative changes in the knee joints of healthy people. Using magnetic resonance imaging (MRI) techniques to evaluate the effects of different intensity levels of exercise, the researchers found that study participants who did one hour of vigorous physical activity three or more times per week were more likely to have bad knees than those who exercised moderately.
The study involved 205 participants who were aged 45-60 years old, healthy and had no knee pain at the start of the study. Although none of them had evidence of knee arthritis, some of them were at high risk for osteoarthritis because of obesity, family history of osteoarthritis, or personal history of knee injury or replacement surgery.
The participants’ physical activity levels were observed over a four-year period and were scored using the Physical Activity Scale for the Elderly (PASE) questionnaire. Averages were taken and categorized into tertiles. Participants who did rigorous activity were classified into the highest tertile which generally consisted of an hour of intense physical activity, at least three times a week.
Degenerative changes in the right knee cartilages were measured using MRI at baseline, on the second and fourth years of the study. Results showed that degenerative changes characteristic of osteoarthritis were most prominent among people who engaged in highest intensity levels of exercise. Those who did the least exercise also showed greater arthritic changes in the knee compared to those who did moderate exercise, however, the difference was not statistically significant.
The study supports previous studies suggesting moderate levels of exercise are recommended to maintain health and prevent joint damage.
Susman, E. Moderate Activity May Be Key to Saving Knees. MedPage Today.