Muscle and Bone Loss
We all know that osteoporosis is the loss of bone mass due to age. My mother had it. She fell and broke her hip as a result and never recovered. There are many similar stories.
Ever heard of sarcopenia? It’s the loss of muscle mass and function, also due to age. It’s a good word, has a nice sound to it, but it’s definitely not good news when it happens. Beginning in our thirties or early forties most of us lose about a quarter pound of muscle per year. Multiply that by twenty or thirty years and we’re talking lots of muscle loss.
The bad news, of course, is that osteoporosis and sarcopenia happen to all of us as we age and there’s little we can do about it, right? You say no? You know that we can take calcium pills daily and reduce the bone loss, right? Well, the calcium may help if your diet is very deficient in calcium. But the effectiveness of calcium supplements is limited. Most effective is the calcium supplement and engagement in weight-bearing exercise, as this promotes calcium deposition into bones, making them stronger.
Let’s get back to sarcopenia. That’s just nature at work. It is what it is. There’s little we can do about it, right? Wrong. Sarcopenia, by the way, is even more prevalent as we age than osteoporosis.
The key to slowing down sarcopenia is a consistent exercise program involving both aerobic and strength training activities. Aerobics improves respiratory capacity, blood flow and aids the process of storing glycogen in muscle cells. This provides the energy we need for daily life and exercise. Strength training improves bone density, muscle mass, stability and balance.
About ten percent of muscle mass is lost from age twenty-five to fifty years. Then, from age fifty to eighty years, another 40 percent is lost. This means a total of fifty percent of muscle mass is lost by age eighty.
Skeletal muscle fibers become smaller in diameter. The result is a reduction in muscle strength and endurance and a tendency to fatigue more rapidly. Because cardiovascular performance also decreases with age, blood flow to active muscles doesn’t increase with exercise as rapidly as it does in younger people.
Aging skeletal muscles develop increasing amounts of fibrous connective tissue, a process called fibrosis. Fibrosis makes the muscle less flexible and the collagen fibers can restrict movement and circulation.
Tolerance for exercise decreases. A lower tolerance for exercise results in part from the tendency for more rapid fatigue and part from the reduction in the ability to eliminate the heat generated during muscular contraction.
The ability to recover from muscular injuries decreases. The number of certain types of cells steadily decreases with age and the amount of fibrous tissue increases. When an injury occurs, repair capabilities are limited and scar tissue formation is the usual result.
While the muscular guy, now in his sixties, who used to hit his golf drives 250 yards and today can only hit it 200 yards is unhappy, his is not the biggest problem. Think about the men or women who started with little and now have almost nothing. Their opportunities to enjoy physical activity are greatly diminished and their chances of injury are now off the charts.
Now to the good news: muscle mass can, for the most part, be retained and even increased by a consistent strength-training program. A progressive strength training program has produced very large gains in strength training even for those in their nineties.
In one study Ben Hurley of the University of Maryland recruited twenty-three healthy men and women in their sixties and seventies to implement strength training for only one of their legs three times a week. In nine weeks the exercised leg increased in muscle size by twelve percent and in strength by thirty percent. Let’s hope they worked on the other leg for the next nine weeks.