Will You Wear Your Knees Out If You Walk or Run?

Osteoarthritis was long considered a disease of wear and tear. The older people got, the more likely they were to have pain and inflammation in their joints. People interpreted that as the consequence of a lifetime of stress and strain from walking, running or other activity. But avoiding physical activity could be counterproductive. New research suggests it may be the best way to manage knee osteoarthritis.

Will Exercise Wear Knees Out or Help Manage Pain?

According to the CDC, over 30 million Americans have some degree of pain, stiffness and swelling in their joints. Nearly half have some discomfort in their knees. How should that be managed? Many people take NSAIDs such as ibuprofen, but such drugs do have downsides. How much does physical activity help?

A systematic review in the BMJ analyzed over 200 studies (BMJ, Oct. 15, 2025). The investigators note that exercise is a mainstream treatment for knee osteoarthritis, but admit that it is difficult to tell which exercise might work best over the long term. Almost two-thirds of the studies analyzed compared some form of exercise to “control,” meaning no exercise. The remainder compared two or more different forms of exercise. While there were differences among the types of exercise, none resulted in more negative outcomes than control.

The researchers concluded that

“In patients with knee osteoarthritis, aerobic exercise is likely the most beneficial exercise modality for improving pain, function, gait performance, and quality of life, with moderate certainty.”

The authors go on to specify that

“Patients should engage regularly in structured aerobic activities, such as walking, cycling, or swimming, to optimise symptom management.”

Looking Back at the Wear and Tear Hypothesis:

If joint use leads to inflammation, then long-distance runners should be more susceptible to knee osteoarthritis than the rest of us. A study from Brigham Young University suggested instead that runners have less inflammation in their knees rather than more (European Journal of Applied Physiology, Dec. 2016).

The scientists measured markers of inflammation before and after the study volunteers, healthy people between 18 and 35 years old, went for a 30-minute run. The markers they examined were GM-CSF (granulocyte macrophage colony-stimulating factor) and IL-15 (interleukin 15). After the run, levels of the compounds dropped in the area directly around the knee. The more times a runner’s foot hit the ground, the lower the level of interleukin 15. Cartilage oligomeric matrix protein (COMP) increased in the blood but decreased in the synovial fluid bathing the joint right after the run.

If Running Lowers Inflammation, Does It Protect the Knees?

The researchers speculate that running and the subsequent decrease in inflammation may help protect the cartilage of the knee and delay the onset of osteoarthritis. People who find that running hurts their knees might consider switching to walking or cycling so they can continue to stay active.