You have probably heard it from a parent, a friend or your own inner skeptic. If you keep running, you will wear your knees out. It is one of the most repeated warnings in exercise, and most people take it as fact.
The best evidence points the other way. A systematic review of 17 studies with 114,829 people was published in 2017 in the Journal of Orthopaedic and Sports Physical Therapy. It found hip or knee osteoarthritis in only 3.5 percent of recreational runners.
In sedentary people who did not run at all, the figure was 10.2 percent. The sitters had roughly three times the arthritis rate of the joggers.
Osteoarthritis is the slow breakdown of the cartilage that cushions a joint. It is the condition most people mean when they say "worn out knees."
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Where the volume of running starts to matter
The same review flagged a group where risk did climb. Among elite competitive runners, 13.3 percent had hip or knee osteoarthritis, higher than both the recreational and the sedentary group.
The authors concluded that very high training loads over many years, not running itself, were the problem. In the data, running up to about 15 years at a recreational level still looked safe for the joints.
Other reviews put a rough number on the risky dose. Studies linking running to higher arthritis risk tended to involve people running more than about 57 miles a week, roughly 92 kilometers. A recreational pace well below that figure sits comfortably in the protective range.
Cartilage is not a passive cushion that only wears down with use. It is living tissue that responds to being loaded.
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The Arthritis Foundation notes that regular running compresses and releases cartilage in the joints, helping to circulate the synovial fluid that nourishes it and keeps inflammation down.
What experts now recommend for your knees
Updated guidance from the American College of Rheumatology strongly recommends regular exercise for knee and hip osteoarthritis. The guidelines put movement, self-management and shared decisions with a doctor at the center of care, not rest.
If you are starting out, build up slowly and keep weekly mileage well under the high-volume threshold. Mixing surfaces and adding strength work for the quadriceps, hamstrings and hips helps your legs absorb impact.
These habits are the ones most consistently linked to healthy joints in long-term runners.
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Pain that lingers after a run, swelling in a joint or a knee that gives way is a reason to pause and see a doctor rather than push through.
Early assessment matters, especially if you already have a prior knee injury, which is itself one of the strongest risk factors for osteoarthritis later on.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.