If you are overweight and experience pain in the knee joint due to a wear-and-tear condition like osteoarthritis, your doctor may offer you one piece of advice: lose weight. This is because the knee is a weight-bearing joint -- and the more pressure you put on it, the more worn it can become. Because your knees must support your excess weight each time you take a step, losing weight can help to relieve pain and improve mobility. While losing weight can help to reduce pressure, it’s up to you to strengthen it.
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Everything Gets Easier
In addition to weight loss itself taking pressure off your knee, weight loss can benefit your knee strength in a different way. When you are overweight, exercise can be difficult. Extra weight can bear heavily on your lungs, which makes you winded faster. Your body also must work harder to move, meaning the heart works harder in an overweight person to circulate blood than in a person at a healthy weight. When you lose weight, you are better able to exercise, which can in turn strengthen the muscles around the knee and improve your joint flexibility.
Less Stiffness in the Knee
Two research studies presented at the 2011 American Academy of Orthopaedic Surgeons meeting connected weight loss in obese adults with reduced knee pain and improved mobility. One study measured 19 obese adults who experienced knee pain before and after bariatric surgery. Following their surgery, the adults reported less knee stiffness and better muscle function. The second research study presented measured the effect of weight loss on those considered morbidly obese -- 100 pounds or more overweight -- who underwent gastric bypass surgery. After the participants lost weight, they experienced reduced pain but did not rate their knee mobility as having changed.
Taking the Next Steps
When you lose weight, you may experience reduced pressure on the knee. But this does not necessarily mean your knee automatically becomes healthy, according to Mike Doherty, a professor at Nottingham University. “Removing excess weight from the painful knee allows it to perform better in terms of function,” Doherty said. The pain may not not get better, "perhaps because the health of the knee itself has not been greatly improved.” When you lose weight, it is up to you to take the next steps to improve knee strength and health.
If You're at a Healthy Weight
When you are at a healthy weight, your knees are better equipped to support your body. And you are better equipped to strengthen them. Still, the link between weight loss and improving knee function chiefly pertains to if you are overweight or obese. Losing weight if you are already at a healthy weight is not necessary to improve knee strength. Also, losing too much weight can have adverse effects on joint health because your body may not be taking in enough nutrients to keep your bones healthy and strong. Remember also that obesity is not the only contributing factor to knee pain. Conditions like rheumatoid arthritis can cause knee pain regardless of your weight.