What's the Evidence?

The evidence is overwhelming: A body needs physical activity to stay healthy.

The more scientists explore the connections between exercise and wellness, the clearer it becomes that physical activity is crucial to optimal health.

The benefits of regular physical activity extend to all people regardless of age or condition—whether they are healthy, at risk for disease, or living with a chronic condition or disability. For people with osteoarthritis (OA), regular exercise offers double benefits: It helps reduce the risk of developing other health problems, and it helps manage OA. Research shows that people with OA who engage in regular aerobic and muscle-strengthening exercise can expect:

• Less pain and stiffness
   
• Increased joint strength and range of movement
   
• Improved function and ability to do activities
   
• Potential delay in disease progression

Physical activity also plays an important role in reducing the risk of these common conditions:

• Obesity (a risk factor for OA)
   
• Heart disease, stroke, and high blood pressure
   
• Type 2 diabetes
   
• Certain cancers (colon, breast)
   
• Depression

How does exercise help?

Scientists are very interested in this question and actively investigating the effects of exercise on OA-afflicted joints. A few things about exercise are known. Exercise strengthens the muscles around joints and keeps them flexible. Strong, flexible muscles do a better job supporting and stabilizing joints than weak muscles. Strong muscles also relieve pain and prevent the pain from activity. Exercise also loosens stiff joints, preserving their ease and range of movement. Finally, exercise that revs up your heart and breathing releases brain chemicals that reduce pain and make you feel good while helping to make or keep you fit.

But, there may be even more that exercise does to help people with OA. One theory is that exercise somehow protects joints from the damaging effects of the disease. In a review of 28 studies of knee OA, exercise was found to be associated with an increased amount of cartilage within knee joints and fewer cartilage defects. Another study discovered a surge of anti-inflammatory activity within the knee joints of women with knee OA immediately after performing intensive quadriceps (thigh muscle) strengthening exercises. While these findings are exciting, further research is needed to fully understand the effects of exercise on joints affected by OA.

Next: Exercise Recommendations