Does Exercise Really Build Strong Bones? Yes, But Not The Way You Might Think
"If you run a young pig on a treadmill, the bones get bigger," says Mark Hamrick, Ph.D., a muscle and bone researcher from Georgia. "But not an old pig." And what's true for pigs, alas, is true for humans as well.
On the bright side, even though exercise can't build bone in later life, we can use exercise, especially high-impact, weight-bearing exercise, to help preserve the bone we've got left.
It's abundantly clear that exercise in youth builds strong bones, and that this benefit sticks around for quite a while. Compared to sedentary folks, for instance, people who were elite athletes in their youth have greater bone mass and bone strength later on, even if they've stopped training.
Jumping, in particular—think cheerleaders—has been shown to boost bone density in young people. In one study involving premenopausal women, jumping 20 times with a 30-second rest between jumps and doing this twice daily can boost bone density to some degree. A different study of premenopausal women involving both jumping and weightlifting also showed some increased bone density.
But what, if anything, these data mean for older women is unclear.
A 2009 Spanish review of the research suggested that while high-impact exercise can enhance bone mass, this is not true in postmenopausal women, precisely the group most prone to osteoporosis and fractures.
On the other hand, British researchers found that both young and older women who performed brief bursts of high-intensity, weight-bearing exercise had stronger bones than those who didn't. But this study showed a simple association, not causality.
Randomized, controlled studies have been largely discouraging. A 2006 randomized study found that moderate-intensity aerobic (not resistance) training did nothing for bone mineral density. A 2017 randomized study of resistance and aerobic training also found no effect on bone mineral density, though this study was in breast cancer survivors who were taking estrogen-blocking medication.
In other words, exercise can't build bone in older people, but it can help preserve bone, as a 2017 systematic review and meta-analysis of 11 randomized trials involving more than 1,000 postmenopausal women showed.
A different 2017 systematic review of 10 randomized studies also showed that high-impact exercise preserved bone density in both peri-and postmenopausal women. Interestingly, this study looked not just at exercise but at standing on a vibrating platform, which also helped preserve bone.
Granted, it may seem like cheating to exercise purists, but other research also suggests that standing on vibrating platforms may boost bone density. In a 2013 Taiwanese study of postmenopausal women, six months of standing on a vibrating platform for five minutes three times a week yielded about a 2% increase in lumbar spine bone density.
As for me, I am one of those exercise purists. True, I can't do all those flips and cartwheels and jumps of my youth, but I can still jog, swim, lift weights, and crank through 50 minutes several times a week on an elliptical machine.
It may take longer—and take more motivation—but for me, at least, genuine exercise is a lot more fun.
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