Biomarker #6: Strength

For years and years — okay decades — I was a cardio-only exerciser.  I swam.  I biked and hiked.  I treadmilled and EFXed.  I cross-country skiied.  Now that I understand the importance of muscle building and maintenance to overall fitness, health and vitality, I train with weights three times a week.  At home, I like the 7-minute workout (app is free), which I repeat three times.  At the gym, I alternate between free weights and machines.  I also take classes at Barre3, an studio routine that uses very light weights and very small movements and is probably the hardest (and most satisfying) exercise I do right now.  All help build muscle, which is far more metabolically active than fat.  That means  muscle burns more calories, even when you’re not using it — so muscle-maintenance is weight maintenance.  But, more important, building and maintaining muscle is a major anti-aging strategy.

More muscle.  Less fat.  That’s the idea.  I’ve written before about the fat-to-lean ratio as a biomarker of aging.  Here I want to talk about strength (as a consequence of muscle) as a biomarker.

Older people are “weaker” than younger people because older people have less muscle mass, and the muscle they do have is less dense and works less efficiently.  Between the ages of 30 and 70, the average person loses 20 percent of the “motor units” (the bundles of muscle fibers and the associated nerves that make up a muscle) in large and small muscle groups, and 30 percent of all muscle cells.  And the cells that remain get smaller. And are marbled with fat.  Less muscle equals less strength.  Less strength leads to “I’ve fallen and I can’t get up” and other such horrors of old(er) age.  Less muscle means less endurance.  Less endurance leads to less activity which leads to decrease in muscle…and so it goes.

The beauty of this — I know this doesn’t sound beautiful, but hold on — is that the progression (or, really, regression) is linear and logical, and therefore both understandable and fixable.  So we can reverse it.  Much of the weakness of older people has less do to with the passage of time than it has to do with the passage of time spent on the couch.  Lack of strength is not a “natural” consequence of aging.  It is a natural consequence of not actively building and maintaining muscle.  Emphasis on the actively.  Want the energy, stamina, strength and endurance that will keep you healthy and vital?  Build muscle.  Want a youthful fat-to-lean ratio?  Build muscle.  When you build muscle you build endurance which helps you…you guess it, build muscle.  And you know what?  It’s even kind of fun.