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For an article I’m working on, I’ve been digging through the literature on sarcopenia, the age-related loss of muscle mass that most of us face starting in our 30s. I’ve found several conflicting estimates of how much muscle you can expect to lose, with a high end of 1-2% per year starting in your fourth decade (from this paper). That’s a lot more aggressive than I’d expected. I get the sense that it’s one of those problems whose implications we’re just now beginning to grasp — so I was interested to see this article by Andrew Pollack in the New York Times, which offers a good introduction to the topic:
Bears emerge from months of hibernation with their muscles largely intact. Not so for people, who, if bedridden that long, would lose so much muscle they would have trouble standing.
(Nice lede!)
Why muscles wither with age is captivating a growing number of scientists, drug and food companies, let alone aging baby boomers who, despite having spent years sweating in the gym, are confronting the body’s natural loss of muscle tone over time.
Comparisons between age groups underline the muscle disparity: An 80-year-old might have 30 percent less muscle mass than a 20-year-old. And strength declines even more than mass…
Much of the article focuses on attempts to agree on a clinical definition of the condition — which would then make it possible for drugmakers to win approval from regulators for drugs to treat it. But the key point for me is:
Researchers involved in the effort say doctors and patients need to be more aware that muscle deterioration is a major reason the elderly lose mobility and cannot live independently.
In other words, I need to start doing my push-ups again. Soon.
And have you found that, like osteoporosis, there is a huge difference between maintaining muscle mass and trying to build it back once it is lost?
Is the 1-2% per year for sedentary individuals?
My impression is yes (to both questions), Hannah. That being said, it is POSSIBLE to build muscle even as an older adult, whereas with bone it’s really more about preserving what you’ve got.
Of course, we’re hearing more and more than the best way to preserve bone health is to strengthen the surrounding muscles (which in turn apply torque that stimulates bone growth and repair). So overall, the message is that we really need resistance exercise, especially as we age.
Actually, bone mass and density can *both* be increased in older adults, and the best remedy is strength training. Yes, impact (e.g., jumping, walking, running) stimulates bone growth, but high-impact activities are out of the question for older adults with arthritis or other joint dysfunction. Strength training causes muscles to exert force on bones, and that stimulus encourages bone remodeling.