Runners put strain on their knees and hip joints, and sooner or later many need a hip replacement. That's what you'd think isn't it? But it's not necessarily the case. The biggest study undertaken so far actually shows that runners are less likely to develop osteoarthritis than less active people. But that doesn't have to mean that running is good for your joints...
OsteoarthritisOsteoarthritis – worn joints to most of us – is one of the most common diseases of aging. Scientists estimate that anywhere between 7 and 25 percent of the population is likely to develop osteoarthritis sooner or later.
A number of studies show that running increases the risk of osteoarthritis and therefore the likelihood that you'll need a knee or hip replacement at some point. However, there are also studies which point to exactly the opposite. Fundamental research has shown that while strain on the joints does lead to wear and tear, it also stimulate the body to produce new cartilage.
StudyThe epidemiologist Paul Williams, at Lawrence Berkeley National Laboratory, assessed just how joint unfriendly running is by looking at data on over ninety thousand men and women. The data had been gathered in the National Runners and Walkers Health Studies, in which sixty thousand runners and thirty thousand walkers had participated.
ResultsAge was the biggest risk factor that Williams uncovered. With every year the risk of developing osteoarthritis and needing a hip replacement increases by five to six percent.
When Walker divided up the runners and walkers according the number of kcals they burned daily, he noticed that the runners had less chance of osteoarthritis or a hip replacement the more calories they burned.
One factor that did increase the risk of damage to joints was bodyweight. The higher the runners' and walkers' BMI, the greater the risk. The stimulatory effect of running on cartilage production is apparently greater than that of wear and tear in lightweight people.
Conclusion"Running does not appear to increase osteoarthritis and hip replacement risk", Williams writes. "These results may not apply to truly elite athletes, but for recreational runners who even substantially exceed current guideline activity levels and participate in multiple marathons annually."
If your BMI is higher than 22-23 then this reasoning doesn't apply to you. In this case frequent running is not good for your joints.