Muscle Mass Beats BMI as Longevity Predictor
A long-term study of more than 3,600 seniors found that more muscle mass was a better predictor of survival than was moderate body mass index. Christopher Intagliata reports
By Christopher Intagliata

SUBSCRIBE TO Science Quickly
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Doctors routinely measure a patient's body mass index, or BMI. And if that weight-to-height ratio points to obesity, the doc might prescribe exercise, to shed the extra pounds. But when it comes to longevity, a focus on weight loss may be misplaced. Because BMI isn't actually a very reliable indicator of life span. A more useful measure, some physicians say, might be muscle mass.
Researchers analyzed BMI and muscle mass data from more than 3,600 seniors in a long-term study. And they tracked which seniors had died, a decade later. Turns out BMI wasn't much good at predicting chance of death.
But muscle mass was: more muscle meant better odds of survival. The study appears in The American Journal of Medicine. [Preethi Srikanthan and Arun S. Karlamangla, Muscle Mass Index as a Predictor of Longevity in Older-Adults]
There's no cause-and-effect here—just correlation for now. But study author Preethi Srikanthan, of U.C.L.A., has this recommendation: "Get up and start moving. Focus on trying to maintain the maximum amount of resistance training that you can, and stop worrying so much about dropping calories." Which could take a little weight off your mind, too.
—Christopher Intagliata
[The above text is a transcript of this podcast.]
Subscribe to Support Independent Journalism
Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.
When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.
Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber