By Dr. Ed
It is a common misperception that the wear-and-tear of regular exercise is bad for joints by damaging and thinning cartilage.
Actually, the opposite is true.
Cartilage is a firm, flexible rubbery connective tissue found in many joints. It’s main function is to protect the bones that meet (articulate) together in a joint. It acts as a shock absorber and a solid lubricant allowing for almost frictionless movement of the bones in a healthy joint.
Cartilage lacks a direct blood supply (Meaning that there are no small arteries delivering blood to the tissue and no small veins draining blood from the tissue). For many years, cartilage was erroneously thought to be an inert, non-metabolic tissue lacking the capacity for repair or further growth. This, however, is not the case. There have been many studies over the last years that have shown that cartilage has a capacity to grow and repair limited damage and respond to a variety of biologic mediators.
Synovial fluid (a viscous straw-colored fluid that occupies many joint spaces and can bath the cartilage) is the Source of nutrients for the cartilage. Synovial fluid is secreted by the synovial membrane which lines the inside of joint. It is a product of filtering the blood and contains many nutrients and supportive factors.
There have been many studies both in humans and an animal models that have demonstrated that moderate, regular weight-bearing exercise that takes the joint through its full range on motion does not lead to thinning of cartilage and probably improves over-all health of the joint. MRI studies of a cohort of middle-age people who exercised regularly for at least twenty minutes three to four times a week overtime revealed thickening of the articular cartilage. It is thought that when A joint moves through its full range of motion, especially with weight-bearing, the increased pressure of the synovial fluid ‘pushes’ nutrients into the cartilage improving its health.
The key here does seem to be moderation. It is known that high impact activities that involve a lot of twisting can lead to accelerated damage of the cartilage of a joint. Examples of these activities would include basketball, football, tennis, soccer.
Besides improving cartilage health regular Exercise or activity can help joint health in at least two other ways.
One is by improving muscle strength around the joint. Stronger Muscles will help stabilize the joint and And help absorb more of the shock relieving the cartilage of some of it’s work.
And regular exercise can Lead to weight loss or may help maintain A healthy weight which again will mitigate some of the stress going through our joints.
So it appears there’s a great deal of truth in the old adage —MOTION IS LOTION.