Why Running Trumps Cycling for Strong Bones

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When done regularly, any intense aerobic workout will improve your overall health. But when it comes to maintaining strong, dense bones — especially as you age — running wins out over cycling, a new study finds.

A team of Italian researchers has been analyzing the impact of various exercises on bone health for years. Most recently, they compared the results of their latest trial, which included ultra-marathoners and moderately active adults, against findings from their previous studies on endurance cyclists.

Pooling all data together, the researchers concluded that, yes, both long-distance running and cycling cause the body to temporarily divert key proteins and hormones away from bone building and use them instead as fuel for the workout. Although this could be bad for bones immediately following a race or a long ride or run, everything falls back into working order shortly thereafter, so these negative effects don’t damage bones in the long run. In fact, in this newest study, the ultra-marathoners gleaned so many metabolic benefits compared to the moderately active participants that the researchers say any temporary halt in bone building after an extensive run is a wash.

This research also reveals that cyclists have a second bone-wrenching problem that runners do not. Because biking is physically taxing but not weight bearing — meaning you don’t have to work against gravity to stay upright as you would when running — calcium continually leaches from the bones into the bloodstream as you pedal. This effect weakens the skeleton over time.

This calcium conundrum also occurred among the elite long-distance runners studied, but to a much lesser degree. And coupled with the research-backed bone-health benefits of weight-bearing exercise, calcium resorption didn’t take much toll on the runners’ bones. 

But before you park your ride permanently, it should be noted that both running and cycling are excellent forms of cardio that’ll rev your metabolism, get you fit, and help fend of health issues. And since variety is key to whole-body fitness, incorporating both is ideal. Secondly, lead researcher Giovanni Lombardi says cyclists traditionally tend to only ride their bikes whereas runners are more apt to shake up their cardio routines and incorporate strength training. This fact may further the bone-health issues that committed cyclists experience.

So while running is most likely the better bet of the two sports for maintaining bone strength, if you’re already a die-hard cyclist who’d way rather clip into pedals than pound pavement, at least juggle up your routine. Suck it up and run or do some other weight-bearing aerobic workout some of the time, and don’t forget to hit the weights, too.