One health issue that’s almost universal in men and women over the age of 55 is osteoarthritis. In fact, some degree of joint degeneration is almost synonymous with aging. However, some people have evidence of osteoarthritis via imaging studies but experience few or no symptoms of the disease. Osteoarthritis is a degenerative disease, one characterized by joint “wear and tear”, but, recently, researchers note that it also has an inflammatory component. Once a joint is damaged, your immune system goes into overdrive and inflammation sets in.
You may have heard people say that exercise is unsafe for people with osteoarthritis, particularly high-impact exercise, like running and jumping, where both feet leave the ground at the same time. While high-impact exercise may not be suitable for people with severe joint problems, a new study suggests that exercise may actually reduce markers of inflammation in the knee joint.
One exercise that’s indisputably high impact is running. For years, even knowledgeable health professionals have advised people with arthritis of the knee not to run. The thought was the impact of the legs hitting the ground and the repetitive nature of running, can further damage the knee joints. However, a new study published in the European Journal of Applied Physiology calls this idea into question.
Arthritis, Inflammation, and Exercise
In this study, researchers measured markers of inflammation in the synovial fluid surrounding the knees of runners. Synovial fluid is a thick liquid inside every joint in your body. Within a joint, like the knee joint, articular cartilage covers the surface of the bones and synovial fluid surrounds the bones and cartilage, acting as a lubricant. When the bones move, the synovial fluid reduces friction, thereby protecting the bone and its articular cartilage when you walk or run. It also supplies nutrients to the cartilage. Without synovial fluid, movements of the joint would not be smooth. With osteoarthritis, the cartilage wears away and the surface becomes inflamed.
In the study, researchers from Brigham University and Intermountain Healthcare analyzed the synovial fluid of young, healthy men and women before and after a run. They were especially interested in the levels of cytokines, markers of inflammation. What they found was levels of two, key cytokines, IL-15 and GM-CSF were lower in synovial fluid AFTER running than before. In other words, these markers of inflammation actually declined after the participants ran. Based on these results, researchers believe that running, and likely other forms of exercise, have an anti-inflammatory effect that may ease the symptoms of osteoarthritis or even slow its progression.
Exercise Has an Anti-Inflammatory Effect
In many ways, this isn’t surprising. A number of studies show that exercise has an anti-inflammatory effect on body tissues, as measured by a reduction in inflammatory markers. This may explain why working out protects against a variety of health problems. We now know that many chronic diseases are linked to low-grade inflammation, including cardiovascular disease, type 2 diabetes, and some forms of cancer. This is one of the first studies showing that exercise potentially reduces joint inflammation. If that’s the case, moderate amounts of high-impact exercise are still appropriate for people with mild osteoarthritis in the knees.
In fact, it may be time to let go of the idea that running and other forms of high-impact exercise are bad for the knees. Data from the Framingham Heart Study, involving more than 5,000 participants, looked for a link between arthritis and high-impact exercise. Researchers questions the participants about their daily activities, including how much they walked and jogged. The participants consented to knee x-rays at the beginning of the study and again at the completion of the study almost 12 years later. The x-rays showed no greater likelihood of arthritis in participants who were the most physically active.
In fact, some experts believe exercise protects against knee osteoarthritis. An Australian study found that people who do intense exercise have thicker cartilage in their knee joints. Another study followed 284 runners and 156 healthy, people who didn’t run for more than 20 years. The results? The runners were less likely to have disabling orthopedic issues. If anything, regular exercise could help you avoid a knee replacement in the future.
What’s more, the biggest risk factor for osteoarthritis of the knee is being overweight or obese. When you weigh more, you place greater stress on your knees. Over time, this can lead to knee issues. In fact, people who are overweight are 45% more likely to develop knee osteoarthritis relative to those of normal weight. Exercise helps with weight control and this indirectly lowers your risk of symptomatic osteoarthritis.
While it looks like most people can safely do high-impact exercise, that doesn’t mean you shouldn’t still train sensibly. Always wear supportive shoes that fit properly and make sure you’re cross-training rather than doing the same exercises over and over. Strength training is important too. Training with resistance helps strengthen the ligaments and muscles that keep the knee bone, or patella, stable. Instability at the knee joint can cause the protective cartilage layer to wear down. If you have knee pain for any reason, get it assessed. If you exercise on an unstable knee, you are at higher risk of knee injury and inflammation.
The Bottom Line
Exercise, contrary to popular belief, may actually be good for your knees and it’s hard to argue with the other health benefits it offers. At the very least, this should reassure you that you’re not in route to a knee replacement every time you run or do another form of high-impact exercise. Make sure you’re strength training though to keep the muscles and ligaments that support your knees strong. Of course, if you have joint issues, always talk to your doctor before doing weight-bearing exercise.
WebMD. “Inflammation May Affect Osteoarthritis”
Knowridge Science Report. “Running actually lowers inflammation in knee joints”
LiveScience.com. “Five Experts Answer: Is Running Bad for Your Knees?”
Brigham Young University. “Study: Running actually lowers inflammation in knee joints”
Medicine & Science in Sports & Exercise: August 2009 – Volume 41 – Issue 8 – pp 1533-1539.
Mediators of Inflammation. Volume 2010 (2010), Article ID 171023, 7 pages
Harvard Health Publications. “Does Running Contribute to Arthritis? Research Says No.”
Runner’s World. “The Benefits of Running”
Am J Sports Med. 2012 Sep; 40(9): 2134–2141.
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