Like to bike? Your knees will thank you and you may live longer, too

We are in the middle of National Bike Month, and cycling enthusiasts love to talk up the benefits of their favorite activity.

"It's definitely my longevity drug," says Brooks Boliek, 65, an avid cyclist of many decades, who used to commute to his office on a bicycle.

A substantial body of evidence supports the health benefits of cycling, everything from strengthening the immune system to boosting the likelihood of living longer. Now, a new study finds people who are in the habit of riding a bike are significantly less likely to have osteoarthritis and experience pain in their knees by age 65, compared to people who don't bike.

The study, which was funded in part by the National Institutes of Health, and published in the American College of Sports Medicine's flagship peer-reviewed journal, included about 2,600 men and women, with an average age of 64 years old. They were surveyed about their physical activity over their lifetime. As part of the study, researchers took X-ray images to evaluate signs of arthritis in their knee joints. "Bicyclers were 21% less likely to have X-ray evidence and symptoms of osteoarthritis compared to those who did not have a history of bicycling," explains study author Dr. Grace Lo of Baylor College of Medicine.

"I was surprised to see how very strong the benefit was," Lo says given the profile of the participants. The people enrolled in the study were not competitive athletes, but rather "average" people, ranging from their mid-40's up to 80 years old. All of them had elevated risks of developing knee arthritis due to weight, family history or former injuries.

The study can not prove cause and effect, given it was an observational study that assessed osteoarthritis at one point in time. But the findings, which are published in the journal Medicine & Science in Sports & Exercise, validate the advice many health care providers give to patients about the benefits of cycling and other non weight-bearing exercises.

"Cycling is very low impact," says musculoskeletal researcher Matt Harkey, an assistant professor at Michigan State University and a co-author of the study. Cycling also helps to build strength in the muscles around the knee which can help protect the joint. In addition, the rhythmic motion of pedaling on a bicycle can move synovial fluid, the viscous, egg white -like liquid in joints that helps reduce friction and absorb shock. "What it does is help to circulate the synovial fluid throughout the joint to help to kind of lubricate [the joint] and provide nutrient delivery to the cartilage," Harkey says.

Of course, there are many types of exercise that are good for health, though cycling seems to have a leg up when it comes to protecting joints. Oftentimes, people give up contact sports such as basketball, as they age, given the risk of injury.

"It can be expected that physical activity in which there is little weight-bearing on joints will be more beneficial than those that need constant stamping," such as running, says Norman Lazarus, a professor emeritus at King's College London, who is in his late 80's and is still cycling. (NPR profiled his cycling research in 2018.)

Lazarus says the results of the new study – pointing to a benefit – are not surprising, though he points out that biking does bring risk of injury. He says it's important for cyclists to understand the risk of overuse injuries as well as the importance of technique and getting a proper fitting bike. Each year, thousands of bicyclists are injured in motor vehicle crashes, and older adults are at higher risk of serious injury. Research shows it's safer to bike on trails or paths separated from traffic.

Risks, aside, research shows biking is good for longevity. "There's good data to support that people live longer when they bicycle," says Lo. She points to a study that found people who cycled one hour per week were about 22% less likely to die prematurely. This was a study of people with diabetes, so it's possible that the benefits are greater for people without the disease.

"This is an exercise [people] can participate in over a lifetime," Lo says, and it can also be done indoors on a stationary bike. "I think that it is a great preventative strategy for many things, including arthritis," she says.

Biking enthusiast Brooks Boliek says cycling brings him joy and a sense of accomplishment. "I'm very goal oriented," he says, and a daily ride gives him something to focus on. "It gives me something to live for."

A sense of purpose that keeps his heart pumping and his muscles strong. He says he'd love to keep riding until the day he dies.

Find Allison Aubrey on Instagram at @allison.aubrey and on X @AubreyNPR.

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