Does running ruin your knees? What the research says

Recreational runners had less knee and hip arthritis than people who sat still. What decades of studies, and MRI scans of first-time marathoners, reveal about running and your knees.

Ask a group of adults why they don't run and someone will mention their knees. Usually it is a warning from a relative, delivered with total certainty: keep pounding the road and you will need new knees by 50.

With the winter running season under way across north India, the warning gets passed around every park and housing society group. The research tells a more interesting story. For most people who run for fitness, the knee seems to cope well, and in several studies runners actually report less knee pain than people who do not run at all.

Does running cause knee arthritis?

The best-known answer comes from a 2017 systematic review and meta-analysis in the Journal of Orthopaedic & Sports Physical Therapy. The researchers screened 25 studies and pooled 17 of them, covering 114,829 people ¹. Among recreational runners, 3.5% had hip or knee osteoarthritis. Among sedentary people who did not run, the figure was 10.2% ¹.

There was a catch. Competitive runners, the people training at high volumes for years, had a rate of 13.3% ¹. So the honest summary is not "running is harmless at any dose". It looks more like a curve, with very little loading and very heavy loading both linked to more arthritis, and regular recreational running sitting in the lower-risk middle. The authors could not pin down a safe upper limit ¹.

These are mostly observational studies, so they show associations, not proof. People who are still running at 55 may simply have had healthier knees to begin with. Even so, if running steadily ground the joint down, you would expect recreational runners to have more arthritis than non-runners. They had less.

Do runners have more knee pain as they age?

A large American study came at the question from another angle. Using data from the Osteoarthritis Initiative, researchers asked 2,637 adults, with an average age of 64, about their running history across their lives. Nearly 30% (29.5%) had run at some point ².

Compared with people who had never run, current runners had lower odds of frequent knee pain (odds ratio 0.71), of arthritis visible on X-ray (0.78) and of symptomatic knee osteoarthritis, meaning arthritis plus pain (0.64) ². After adjusting for other factors the results held up, although the X-ray finding weakened ². The authors' conclusion was blunt: in people without osteoarthritis, running does not appear to be detrimental to the knees ².

A 2023 updated systematic review in the Orthopaedic Journal of Sports Medicine pulled together 17 studies with 7,194 runners and 6,947 non-runners ³. Knee pain was significantly more common in the non-runners. Most studies found no difference in X-ray signs of arthritis or in cartilage thickness on MRI, though one did find more bony spurs in runners ³. In one of the included studies, 2.6% of runners went on to need a total knee replacement, compared with 4.6% of non-runners ³.

That review is careful to say "short term". Average follow-up for the runners was 55.8 months, a little under five years ³. Within that window, running was not linked with worse symptoms or worse X-rays, and it may have offered some protection against general knee pain ³.

What a first marathon does to a middle-aged knee

The most surprising study looked inside the joint. Researchers in London recruited 115 adults planning their first marathon, with a median age of 44, and scanned their knees with MRI before training and again after the race ⁴.

Before any training had started, the scans already showed plenty of what sounds like damage. Across the 142 knees of the 71 runners who finished the marathon and had both scans, 65% showed some cartilage damage and 36% had meniscal tears, in adults fit enough to sign up for a marathon ⁴.

After the marathon, swelling in the bone just beneath the cartilage of the shin bone (bone marrow oedema) had improved, with a similar trend at the thigh bone ⁴. The cartilage on the outer side of the kneecap had worsened slightly, yet the runners had no symptoms from it, and the existing meniscal tears did not progress ⁴.

Your knees are not a car tyre that wears thin with every kilometre. They are living tissue that responds to the load you give them.

Two lessons stand out. A scan finding in an adult knee is common and does not automatically mean trouble. And a few months of training appeared to help some structures while stressing others, which is exactly why the way you build up matters more than whether you run at all.

Who should be more careful?

The reassuring studies above mostly describe people without existing arthritis ². If you already have osteoarthritis, a past ligament or meniscus injury, or knee surgery behind you, the findings do not automatically transfer to you. It is worth getting a plan from a physiotherapist or sports doctor before you start.

The other group is the very high-volume crowd. The 13.3% figure for competitive runners is a reminder that dose still matters ¹. Most office workers fitting in three or four runs a week are nowhere near that end of the curve.

And if knee pain stops you, it is usually worth looking at what changed recently: a sudden jump in distance, a new hilly route, a race on the calendar that pushed the build-up too fast. Fixing the load is the first thing to try, before assuming your knees are wearing out.

How to start running without worrying about your knees

The World Health Organization recommends that adults get at least 150 minutes of moderate-intensity physical activity a week, and it estimates that 31% of adults worldwide do not meet the recommended levels ⁵. Running is one of the cheapest ways to get there. Here is a sensible way to begin this week:

1. Start with run-walk intervals. Try one minute of easy running and two minutes of walking, repeated for 20 to 25 minutes, three times this week.
2. Keep the pace conversational. If you cannot speak in full sentences, slow down. Easy running builds the joints, tendons and heart without overloading any of them.
3. Build slowly. Add a little running time each week rather than chasing distance, and take an easier week every so often.
4. Strengthen the legs twice a week. Ten minutes of sit-to-stand squats from a chair, step-ups on a stair, glute bridges and calf raises gives the muscles around your knees more capacity to share the load.
5. Listen to the right signals. Mild stiffness that eases as you warm up is common. Pain that makes you limp, swelling, locking or pain that gets worse as you run means stop and get it checked.

In Delhi NCR and other smoggy cities, check the air before you head out on winter mornings; our guide to exercising when the AQI is high explains when to move the session indoors.

If you have a heart or joint condition, are pregnant or take regular medication, speak to your doctor before starting a new running routine.

For everyone else, the evidence points one way. Sitting still is not protecting your knees. Sensible, regular running is far more likely to be a friend to them than an enemy.

General information for healthy adults, not medical advice. Speak to a doctor before changing your training or diet if you have a health condition, are pregnant or take regular medication.