DEAR DOCTOR K: I am in my mid-30s and like to run for exercise. The problem is that I have creaky knees. I haven’t experienced pain yet, but my husband thinks I’m wearing my knees out and that I’ll give myself arthritis. Is this possible? Should I give up on vigorous exercise?
DEAR READER: When I was little, my father often told me to “slow down or you’ll wear out your joints.” (I guess I was a little hyperactive.) A lot of people — like your husband and like my father — think that our joints are like car tires. Which is to say, they believe using them wears them out, and the more you use them, the faster they’ll need to be replaced. While this may be true for tires, the same cannot be said for your joints.
For example, I had a joint wear out in my right hip. My hip bone was rubbing against my thigh bone, and it hurt. Of course, every time we stand up, walk or run, we are putting pressure on the hip joint. But we’re putting pressure on both hip joints, since we’re using two legs. Yet my left hip was completely normal. I got a right hip replacement, and the pain has been gone ever since.
Many of my patients are like me: just one bad hip or knee. So it’s not as simple as saying you wear out your joints by using them.
The risk factors that actually lead to arthritis are advanced age, obesity, a family history of arthritis, injury (especially a fracture that involves the joint), and rheumatoid arthritis or another type of chronic joint inflammation.
So, although it’s clear that running stresses the knees, ankles and other joints that bear weight, research doesn’t clearly show that running is bad for the joints. In fact, our muscles actually protect our joints by reducing some of the pressure on them. Not exercising regularly can weaken the muscles and thereby make the joints more prone to damage.
That said, a sudden, severe injury (a fracture or ligament tear) could cause cartilage damage that can lead to osteoarthritis. Or a muscle injury can weaken a muscle that helps to protect a joint. I tell my patients to start an exercise program gradually, and to back off if they feel pain during or after exercise. A joint will tell you if it is under excessive stress while you exercise, by causing you pain. Listen to your joints. If running ever hurts, try swimming or biking instead.
So why did one of my hips go bad, but the other didn’t? I had an injury to the main muscle in my right thigh when I was a teenager. That muscle has never been as strong since. Years of jogging on asphalt probably put too much stress on my right hip. I should have stopped jogging when my right hip started to hurt, but I didn’t. Yes, doctors can make dumb mistakes.
Bottom line: You can’t “use up” your joints by using them. In fact, moving is better than not moving — for your joints and for your overall health.