Muscle Mass Beats BMI as Longevity Predictor – Who Knew!?

I’ve written a couple of times (here and here) about my dislike of the imperfect science of body mass index. In particular, I’ve stated that it does not accurately assess the elderly because of low muscle mass. The elderly are likely to have a “healthy” BMI despite being anything but. As people age they lose weight through muscle loss. This brings their BMI down and may even bring it into what is considered an optimal range. The problem is muscle mass loss reduces strength, which increases the likelihood of falls and a reduced ability to exercise. The last point is particularly problematic.

Now new research shows that 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]. For more information see here.

Critics argue that it’s nearly impossible for the elderly to build muscle. I think they are missing the point. It’s not necessarily that the elderly need to bulk up. It’s that they need to minimize muscle loss. This is done through resistance training. Anyone, yes even the elderly, can resistance train. By doing so muscle loss is minimized. This may mean you don’t fit into the BMI scale perfectly, however, it does mean you are healthier. So, here’s to weight lifting!