Regularly pounding the pavement may take a pounding in your joints, but a new study presented at the European Congress of Endocrinology shows that exercise that puts a greater strain on bones—like running—may improve long-term bone health more than non-weight-bearing activities.
The study looked at three metabolism- and energy-regulating hormones (glucagon, leptin, and insulin) and two bone proteins (osteocalcin and P1NP) in 17 mountain ultra-marathon runners. The researchers measured these hormones and proteins both before and after a 65 km (40 mi) mountain ultramarathon run and compared them to the levels in 12 adults of the same age who did low to moderate physical exercise instead of the race.
After the trial, the ultramarathon runners had higher levels of glucagon than the control group (which indicates a demand for energy) and lower levels of leptin and insulin than the controls (which indicates a lower energy level). The runners' levels of both osteocalcin and P1NP also decreased, which the researchers say suggests the athletes may be using their energy to power their metabolism rather than using it for bone formation.
The most important takeaway, however, is that the ultramarathon runners had higher P1NP levels at rest compared to the control group. Translation: the runners may not be using energy and P1NP to strengthen bones while racing or running, but could make up for those gains at rest, giving them better bone health in the long-run. (Boost bone health with these dairy-free foods.)
Numerous other studies have shown that cycling—while an awesome cardiovascular workout—doesn't encourage improvements in bone mass, and can even result in low bone mineral density in certain areas.
"Our findings suggest that those at risk of weaker bones might want to take up running rather than swimming or cycling," says Dr. Giovanni Lombardi, lead author of the study, in a press release. Because running exerts a higher physical load on your bones, that physical force might stimulate osteocalcin in the bone tissue to signal to the pancreas to help meet its energy needs in the long-term, says Dr. Lombardi.
That said, if you're an avid cyclist don't let this news scare you away from tackling that 100-mile road race or hitting up SoulCycle. Just consider adding some running into your routine, and you may be able to add some bone-boosting effects. Also keep in mind that this study is examining ultra-marathoners—AKA a really badass crew of serious, long-distance runners—so we don't know whether the same effects can be seen in someone training for, say, a 10K.
And if you're a marathon runner? Rest easy knowing that your bones are working hard. (If this just convinced you to run one, try one of our training plans.)