As reported By Christie Aschwanden in the Washington Post
While out on a run recently, I passed a hiker on the trail. “My knees hurt just watching you,” he told me, shaking his head. It was a variation on a comment I hear over and over: Keep running like that, and you’ll give yourself arthritic knees.
The notion that running causes wear and tear on the joints that could spur arthritis makes some intuitive sense. But is it true?
“There’s a perception out there that somehow you’re wearing out your joints if you’re out there running,” Williams says, but the thousands of runners in his study show this just isn’t so. “I’ve recruited people who were doing 60 or 70 miles per week, and we’ve followed them over time,” he says. “If there had been an effect, we would have seen it.”
The notion that running causes osteoarthritis arises from a misperception about how joints work, says Alex Hutchinson, a science journalist. “People think the joint is just a static, inert hinge that wears down, but it’s actually a dynamic, living thing that can respond to stress and adapt and get stronger,” he says. Rather than wear down cartilage and other joint tissue, running appears to strengthen them, Hutchinson says.
The latest research shows that osteoarthritis isn’t just a result of wear and tear on your joints, says Patience White, vice president for public health policy and advocacy at the Arthritis Foundation. Instead, the disease arises from an interplay between environment and genetics. The strongest risk factors for osteoarthritis are obesity and family history, says White, who is also a professor or medicine and pediatrics at the George Washington University School of Medicine and Health Sciences.
Every extra pound you carry is akin to four pounds on your knees, White says: “If you lose five pounds, that’s like 20 pounds across your knees.” But obesity’s role in osteoarthritis isn’t confined to the extra stress it can put on joints. “People who weigh more also get more osteoarthritis in their wrists, so it’s not just about mechanical loading through the joint,” Hutchinson says. Fat tissue is metabolically active and secretes inflammatory hormones that interact with everything in the body, including cartilage and joints, he says.