Muscle Metabolism - Muscle Loss
"We tend to think of muscle loss as a problem of old age," says researcher Chhanda Dutta. "But it’s something that starts much earlier in our lives."
Men and women begin to lose significant muscle mass in their 40s and 50s. Some of that is due to age and some is due to a sedentary lifestyle. The chief of the Clinical Gerontology Branch at the National Institute on Aging (NIA) in Bethesda, Maryland also attributes too little protein in the diet can accelerate the loss.
Unfortunately, most people think they’re fine because the early muscle loss doesn’t hold them back. That’s until they reach a point where they can no longer go grocery shopping or live independently. At that point you are in trouble.
"There are probably several dozen ways sarcopenia (pronounced SAR-co-PEEN-yuh) develops, and that’s part of the problem of trying to treat it,"says John Morley, professor of geriatric medicine at St. Louis University in Missouri.
Among the causes:
* Slowdown in muscle metabolism. As we get older, our ability to synthesize muscle protein decreases. You can increase the size of the muscle fibers you have, but you’re not really making new muscle tissue.
* Too little muscle-stimulating physical activity. For 80 to 90 percent of adults, if they don’t do the right kind of physical activity regularly, they’re going to end up with sarcopenia, Research shows that seniors benefit from a regular regimen of tennis and my Senior Tennis League shows it. Without the activity on a regular basis, they’re going to end up with sarcopenia by the time they’re in their 60s and 70s. Even people who walk or run regularly may be on the road to later problems. That’s because aerobic exercises like walking, running or cycling don’t challenge some of your major muscle groups.
* Genetic differences. We all know middle-aged people who look like they have as much muscle as the average 25-year-old. That’s probably because they’ve inherited good genes. They’ve probably also stayed reasonably active throughout their life. But those people are the exceptions.
* Gender differences. While both men and women lose muscle as they age, the functional consequence for women is huge. That’s because women start out with less muscle and wind up much weaker. Since women live longer and are more likely to live alone, they’ll be dealing with the effect of sarcopenia much more than men.
* Hormonal deficiencies. Testosterone (in men) and estrogen (in women) stimulate the growth of muscle tissue, but both decline with age. Also critical for muscles is insulin-like growth factor (IGF), which drops dramatically as we grow older. But don’t assume that taking hormones will reverse the effects of muscle loss.
* Changes in diet. We eat less as we get older. In particular, we eat less protein, the nutrient that builds muscle tissue.
* Loss of nerve cells. As we age, we lose not just brain cells, but also motor nerve cells in our spinal cord that send information out to the muscles. By the time we’re into our 60s and 70s, we’ve lost up to half our motor nerve cells.
Without nerve cells to stimulate them, muscles wither away. The remaining healthy motor nerve cells can compensate by adopting the "orphaned" muscle fibers.
How can you avoid the damage done by muscle loss (sarcopenia)?
* "Resistance exercise is what people should be doing before they think of anything else," says st. Louis University’s John Morley. The results can be dramatic.
"Women in their 40s and men in their 60s lose muscle strength at a rate of 12 percent per decade," says Ben Hurley. A professor of exercise physiology at the University of Maryland in College Park. (Hurley is married to Nutrition Action senior nutritionist Jayne Hurley.)
But with two months of resistance training, they can increase their strength by 40 percent. "In other words, they can reverse two decades of typical muscle strength deterioration in 50 days," says Hurley.
Strength building has other benefits. "Women who do strength training gain more self-confidence and self-esteem, they sleep better, and they’re less likely to be depressed." says Tuft’s Miriam Nelson.
Strength training also makes aerobic exercise more enjoyable because you’re more fit and less prone to injuries. The key to stemming muscle loss with exercise is to strengthen the big muscles around the thighs, arms, shoulders, and back.
To gain muscle you need to consume 50 percent more protein than the RDA level. To reach that much, your daily protein target (in grams) should be about half your weight (in pounds). That’s about 65 grams of protein a day for someone who weights 125 pounds. I’ve found that to be effective in my own case.
The good news is that you can get enough protein without cooking elaborate meals every night. Who knew that half a cup of cottage cheese or a chicken breast could help keep you looking and feeling younger? Be sure to choose low fat or fat free cottage cheese for an even better benefit!
Men and women begin to lose significant muscle mass in their 40s and 50s. Some of that is due to age and some is due to a sedentary lifestyle. The chief of the Clinical Gerontology Branch at the National Institute on Aging (NIA) in Bethesda, Maryland also attributes too little protein in the diet can accelerate the loss.
Unfortunately, most people think they’re fine because the early muscle loss doesn’t hold them back. That’s until they reach a point where they can no longer go grocery shopping or live independently. At that point you are in trouble.
"There are probably several dozen ways sarcopenia (pronounced SAR-co-PEEN-yuh) develops, and that’s part of the problem of trying to treat it,"says John Morley, professor of geriatric medicine at St. Louis University in Missouri.
Among the causes:
* Slowdown in muscle metabolism. As we get older, our ability to synthesize muscle protein decreases. You can increase the size of the muscle fibers you have, but you’re not really making new muscle tissue.
* Too little muscle-stimulating physical activity. For 80 to 90 percent of adults, if they don’t do the right kind of physical activity regularly, they’re going to end up with sarcopenia, Research shows that seniors benefit from a regular regimen of tennis and my Senior Tennis League shows it. Without the activity on a regular basis, they’re going to end up with sarcopenia by the time they’re in their 60s and 70s. Even people who walk or run regularly may be on the road to later problems. That’s because aerobic exercises like walking, running or cycling don’t challenge some of your major muscle groups.
* Genetic differences. We all know middle-aged people who look like they have as much muscle as the average 25-year-old. That’s probably because they’ve inherited good genes. They’ve probably also stayed reasonably active throughout their life. But those people are the exceptions.
* Gender differences. While both men and women lose muscle as they age, the functional consequence for women is huge. That’s because women start out with less muscle and wind up much weaker. Since women live longer and are more likely to live alone, they’ll be dealing with the effect of sarcopenia much more than men.
* Hormonal deficiencies. Testosterone (in men) and estrogen (in women) stimulate the growth of muscle tissue, but both decline with age. Also critical for muscles is insulin-like growth factor (IGF), which drops dramatically as we grow older. But don’t assume that taking hormones will reverse the effects of muscle loss.
* Changes in diet. We eat less as we get older. In particular, we eat less protein, the nutrient that builds muscle tissue.
* Loss of nerve cells. As we age, we lose not just brain cells, but also motor nerve cells in our spinal cord that send information out to the muscles. By the time we’re into our 60s and 70s, we’ve lost up to half our motor nerve cells.
Without nerve cells to stimulate them, muscles wither away. The remaining healthy motor nerve cells can compensate by adopting the "orphaned" muscle fibers.
How can you avoid the damage done by muscle loss (sarcopenia)?
* "Resistance exercise is what people should be doing before they think of anything else," says st. Louis University’s John Morley. The results can be dramatic.
"Women in their 40s and men in their 60s lose muscle strength at a rate of 12 percent per decade," says Ben Hurley. A professor of exercise physiology at the University of Maryland in College Park. (Hurley is married to Nutrition Action senior nutritionist Jayne Hurley.)
But with two months of resistance training, they can increase their strength by 40 percent. "In other words, they can reverse two decades of typical muscle strength deterioration in 50 days," says Hurley.
Strength building has other benefits. "Women who do strength training gain more self-confidence and self-esteem, they sleep better, and they’re less likely to be depressed." says Tuft’s Miriam Nelson.
Strength training also makes aerobic exercise more enjoyable because you’re more fit and less prone to injuries. The key to stemming muscle loss with exercise is to strengthen the big muscles around the thighs, arms, shoulders, and back.
To gain muscle you need to consume 50 percent more protein than the RDA level. To reach that much, your daily protein target (in grams) should be about half your weight (in pounds). That’s about 65 grams of protein a day for someone who weights 125 pounds. I’ve found that to be effective in my own case.
The good news is that you can get enough protein without cooking elaborate meals every night. Who knew that half a cup of cottage cheese or a chicken breast could help keep you looking and feeling younger? Be sure to choose low fat or fat free cottage cheese for an even better benefit!
posted by Stan Kent at
10:39 AM
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