Running does not cause arthritis. This is actually not a new finding. Researchers have know for years that running will not cause arthritis. Runners in general have a much lower chance of developing osteoarthritis than their non-running counterparts.
Runners entering their mid-life are undertstnably concerned that their running habit might be putting them at risk. Their friends chastise them for running and for putting their knees at risk. Thankfully, most runners can stash those fears and tell their friends that they’re simply wrong. Running will not cause arthritis…and now research is starting to reveal that running might actually protect the knee from developing arthritis.
In order to understand this better we need to learn to think from both a biological perspective as well as a mechanical perspective.
Form a mechanical perspective it would seem intuitively obvious that pounding your legs into the pavement by running day after day and year after year would wear our parts out faster. As an Orthopedic surgeon for nearly 2 decades I can’t begin to count or tell you about all the times thats something with seemingly sound intuitive reasoning was found to be inaccurate or false. The body has an incredible way of doing that. It is not only a mechanical wonder… it is a biological wonder with hundreds of thousands of proteins, chemicals, ions and hormones working throughout the body and governing the thousands of processes that keep us in homeostasis. Those compounds and proteins act upon our complex mechanical systems … and their actions can be profound. Therefore theories such as running causes arthritis are far too mechanistic.
Our knees joints are protected by articular cartilage. Cartilage is a firm, hardy, exceedingly smooth surface. It has a very slow metabolism, and very little if any regenerative potential. Our cartilage is fed not by blood vessels, but by nutrients found in the fluid within our joints. When you walk you force that joint fluid under pressure into the cartilage surface. In normal joint fluid there are many hormones, and chemical compounds. These chemical and hormones help regulate the health of the cartilage and the other structures within our knee joints.
These chemicals within our knees can change. They can change by the hour, week, month or year. If we take a small amount of fluid from a normal knee and run some tests on that fluid we will find different chemicals and different concentrations of chemicals then we would in a knee with osteoarthritis .
Osteoarthritis is by definition an inflammatory disorder. Inflammation is very complex process. A substance known as cartilage oligomeric matrix protein or COMP is a protein found in higher concentration in the knees of people with osteoarthritis. Thus it is thought to be a marker for osteoarthritis. The lower the concentration of COMP the less chance that your arthritis will progress. Other inflammatory compounds such as cytokines and interleukins are also found in different concentrations in joints which are healthy versus those which are degenerating or deteriorating.
In a recent study, a number of volunteers were tested. One set of volunteers ran for 30 min. One group sat for 30 minutes. Before and after their run a small amount of joint fluid was taken to be tested. The scientists found that COMP, the marker for joint degeneration decreased immediately after a run… and increased after a period of sitting. Not only that, they found that COMP was higher in the blood of the runners. Therefore it appears that the act of running functioned to mechanically push the COMP out of the knee and into the bloodstream where it could not harm your knees.
This is a fascinating area of study and great news for runners in their mid-life who are concerned that their running might ruin their knees. It is safe to say that the current research suggests that:
- Running does not cause arthritis and …
- Running appears to prevent arthritic changes by decreasing the amount of inflammatory chemicals found inside your knees after a run.
Stay tuned for more on this very interesting topic