Muscle Mass, BMI, and Longevity

A study published last February in the American Journal of Medicine, Muscle Mass as a Predictor of Longevity in Older Adults, finds that muscle mass is a more important positive predictor to longevity in older adults than obesity is a negative predictor, as determined by Body Mass Index (BMI). Of course, it’s obesity at the lower end of the bathroom scale that seems not to matter so much.  If being a little overweight matters at all, it’s on the positive side.  While the morbidly obese are still goners sooner than later, being skinny when you’re old has been shown to be a detriment to long life.

As you can imagine, muscle mass is easier to acquire when young than when you’re old. When we’re old it’s easier to keep what we built up years earlier than to get it anew at an advanced age. But all is not lost. While muscle declines and fat increases as we get old, the process can be slowed down or even reversed to some extent with resistance training, i.e. weight lifting with barbells.

Running, walking and bicycling are not the sort of weight-bearing exercises that increase muscle mass, except in the legs. Total skeletal muscle mass depends upon the sort of training outlined in Mark Rippetoe’s Starting Strength, 3rd Edition. A 4th edition may be coming soon, but I see no need to wait for it.

Muscle mass seems to almost be an elixir for the ill effects of aging, if you follow the research that’s being done on it these days.  It promotes glucose metabolism to prevent insulin resistance leading to type 2 diabetes.  It speeds recovery from prolonged illness in older adults. It improves balance and makes life more fun. It makes life easier so that one is not so dependent on others for heavy lifting like moving furniture or getting the lawn mower into the trunk of the car.

None of this means you should give up the cardiovascular workouts. You still need that, but apparently it’s a mistake to rely solely on it for living longer.

The American Journal of Medicine Srikanthan-Karlamangla study is available at the link above, and here is another interesting piece: Muscle Mass Predicts Longevity Better Than BMI.

Check out this mp3 audio at Scientific American.

I might be too old for this:


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