Recommended levels of physical activity are safe and provide many health benefits
A new Centers for Disease Control and Prevention (CDC) study shows that meeting recommended levels of physical activity (150 minutes per week) does not increase the risk of knee osteoarthritis among middle-aged and older adults.1 Also, the study shows that high levels of physical activity (at least 300 minutes per week) may increase risk of knee osteoarthritis in this population, which is consistent with other studies.2-4
The study results suggest that adults should continue to strive to meet the goal of 150 minutes per week of moderate aerobic activity without worrying about increasing their risk of knee osteoarthritis. However, it is also important to remember that high levels of physical activity (at least 300 minutes per week) could increase the risk of knee osteoarthritis.
Meeting Recommended Levels of Physical Activity Does Not Increase the Risk of Knee Osteoarthritis
According to the US Department of Health and Human Services 2008 Physical Activity Guidelines,5 most health benefits for adults occur with at least 150 minutes (2 hours and 30 minutes) a week of moderate-intensity physical activity in bouts of at least 10 minutes each time. The health benefits of this amount of physical activity include a lower risk of the following:
- Early death
- Heart disease
- High blood pressure
- Breast cancer
- Colon cancer
- Poor cognitive function
- Weight gain
Moderate aerobic physical activities are those activities that produce some increase in heart rate or breathing. For those who already have arthritis, moderate physical activity has also been shown to help reduce joint pain and improve their confidence in their ability to make changes that will help manage their arthritis. Walking, biking, and swimming are recommended as joint-friendly activities for people who have arthritis. People who do not have arthritis can also engage in these activities at recommended levels without increasing the risk of knee osteoarthritis.
The CDC study used data from the Johnston County Osteoarthritis (JoCo) Project, an ongoing population-based prospective cohort study of knee and hip osteoarthritis in Johnston County, North Carolina. The JoCo study originally enrolled 3,068 community-dwelling, non-institutionalized, white and black residents, age ≥45 years at baseline from 1991–1997 from 6 townships. The findings from the JoCo study are based on those seen at both the first follow-up (1999–2004) and second follow-up (2005–2010) and includes 1,528 participants followed for a median time of 6.5 years.
1. Barbour KE, Hootman JM, Helmick CG, et al. Meeting physical activity guidelines and the risk of incident knee osteoarthritis: The Johnston County Osteoarthritis Project. Arthritis Care Res (Hoboken). Aug 27 2013.
4. McAlindon TE, Wilson PW, Aliabadi P, Weissman B, Felson DT. Level of physical activity and the risk of radiographic and symptomatic knee osteoarthritis in the elderly: the Framingham study. Am J Med. Feb 1999;106(2):151-157.
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