How Bad Is It for Your Knees to Run Every Day?

If you try and go from zero to a half marathon, you’re going to have a bad time

I hate cardio, so I don’t run. That’s the truth. But if anyone asks, I fall back on one of the more commonly accepted arguments against running — particularly, that it’s hell for your knees. With gyms closed and nowhere else to go, though, lots of people have taken up running as a necessary break from their monotonous quarantine day. And the thing is, although running has the potential to damage your knees, it doesn’t have to. 

According to Danny McLoughlin, a researcher for running sneaker review site RunRepeat, the relationship between running and knee damage is complicated. “You could ask five medical professionals and get five different answers,” he says. “But as a runner, the short answer is, too much running too soon is bad for your knees.” This is true of any exercise — doing too much too soon can have painful consequences. For running, your knees tend to be the body part that suffers those consequences because they bear much of the pressure and shock absorption from our feet repeatedly hitting the pavement. 

“If you’re going to run more than before, you have to build up gradually,” explains McLoughlin. “For example, a new runner won’t be able to go from zero exercise to a 10k. If they do, they’ll hurt themselves. Similarly, a regular runner will struggle to go from running 20 kilometers [about 12.5 miles] a week to running 60 kilometers [about 38 miles] a week. You need to give your body time to adjust, heal and repair the damage you’ve done on your run.”

McLoughlin recommends, then, that new and experienced runners alike keep track of their runs and establish a plan to gradually increase their pace or distance (McLoughlin uses the app RunKeeper Pro, himself). To give yourself time to rest, you should only run four to five days a week, maximum. 

But what about long-term, chronic knee damage? 

This is among the more hotly contested issues in running, with some concerned that a running hobby will eventually lead to arthritis. Currently, though, the general medical consensus is that running will only lead to arthritis if you’re genetically predisposed to arthritis, anyway. “Your parents decide if you’re going to have arthritis or not — it’s genetic,” Lewis Maharam, fellow of the American College of Sports Medicine, told LiveScience. “Jogging, or running, itself will not cause the arthritis. If you already have arthritis, and you have bone and bone contact, and no cartilage in your knee, running will make it worse.” 

Basically, if other people in your family have arthritis, then you could be at risk: Running could trigger arthritis symptoms, as it can wear down the cartilage in the knee leading to inflammation in the joints. But in all likelihood, you would experience these symptoms eventually, anyway. It’s also hypothetically possible to suffer an injury from running that leads to long-term pain, but again, this isn’t necessarily the result of running itself. Instead, like McLoughlin explains, it’s more likely the result of overexertion or improper form. (Per MEL staff writer Quinn Myersguide to proper form, runners should strive to “run quietly,” landing on the balls of their feet rather than their heels; this technique, along with stretching and proper sneakers, can help prevent knee damage, too.)

Running also may exacerbate problems in people with prior knee injuries, or those who have anomalies like a tilted pelvis or uneven leg lengths. Overweight people are more likely to experience some knee strain, too, but this can be managed with McLoughlin and Myers’ recommendations. 

“It’s not always easy to get right,” McLoughlin says. “I’ve run a couple of marathons, 10s of half marathons and more 5 and 10Ks than I can count. Recently, after a year-long break, I tried to get back into running and went straight from zero to my old schedule. I let my ego get in the way, injured my knee and if it wasn’t for coronavirus, I would have missed the Barcelona marathon I was planning on running. As it stands, it’s been rescheduled and I’m hoping to build up slowly to be ready in time.” 

For the majority of people, the benefits of running still outweighs the potential risks. Even among those destined for arthritis, staying active can help ease symptoms in the future. “If you set realistic targets (and don’t tell fibs — especially to yourself — about your current weekly mileage), then it shouldn’t be more than you can handle,” says McLoughlin. 

So… I guess I need to find a new excuse.