When it comes to arthritis, runners are much better off than walkers, according to a study published in the the journal Medicine & Science In Sports & Exercise.
Although the finding may seem counterintuitive, it’s based on a slew of data from the National Runners' Health Study. The paper, “Effects of Running and Walking on Osteoarthritis and Hip Replacement Risk,” considers osteoarthritis (OA) and hip replacement (HR) rates among 75,752 runners and 14,625 walkers.
The paper is based on years of self-reported data from the study's participants. Runners kept logs for 7.1 years, and walkers for 5.7 years. The numbers were then compiled and crunched by epidemiologist Paul Williams, a researcher in the Life Sciences Division at Lawrence Berkeley National Laboratory.
The results revealed three surprises. The first is that runners have about half the risk of osteoarthritis and hip replacement as walkers. The difference, Williams says, is due to the effect of running on body mass index. Running lowers BMI more than walking, and lower body weight could be what prevents arthritis.
The second was that people who ran more had a 15-18 percent lower rate of OA and a 35-50 percent lower rate of HR. This is likely for the same reason.
Finally, the research also showed that extra hours of non-running exercise increased rates of OA and HR—a finding that seemed to suggest that humans are better designed for straight-ahead motion rather than the twisting or torqueing involved in other sports.