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The following article appeared in the Tufts University Health and Nutrition letter in March 2003.

Are You Doing All You Can to Fight Sarcopinia?

Muscle loss that leads to frailty in old age is not inevitable.

People worry about having a heart attack when they get older or falling victim to cancer, Alzheimer's, or other illnesses. But much of the disability associated with aging is not about disease. It's about creeping frailty. That's what stops many older people from being as busy and energetic as they'd like or even from living independently.

You're probably well aware by now that some of the frailty comes from porous, gradually weakening bones. And you know the name for it- Osteoporosis; osteo for bone, and porous for pore. But even more universal than a critical loss of bone is frailty that stems from a loss of muscle. And it has a name too - sarcopenia; sarco for flesh or muscle and penia for loss.

The term was coined back in the late 1980s by Irwin Rosenberg, MD, dean of the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts (and the editor of this newsletter). At that time, research by Tufts scientists had shown that muscle loss occurs as a matter of course with aging, and that those losses are dramatic ones.

Sarcopenia generally starts to set in around age 45, when muscle mass begins to decline at a rate of about 1% a year. Not surprisingly, as muscle mass decreases, so does muscle strength. And as strength goes, so does physical functioning- the ability to climb stairs, do chores, dance, take walks, enjoy a day of touring, go grocery shopping, or accomplish other activities.

The muscle loss occurs in people of all fitness levels, even master athletes. But those who have less muscle to begin with pay a higher price. Women in particular face risk from lost muscle mass. After adolescence, "women have about one third less muscle mass than men", says Miriam Nelson, Ph.D., director of the Center for Physical Activity and Attrition at Tufts. "So they're muscle loss has an impact sooner. More women end up in nursing homes. Also, women live longer- so they're older but much weaker," she explains.

Why does sarcopenia happen? So far, the best guess is that it's caused by a gradual loss of certain nerve cells that link the brain to the muscles; in turn, loss of chemical connections between the two causes a loss of muscle cells themselves. Other age-related declines may play into it as well. For instance, the immune system gradually weakens, and that, some searchers suggest, may increase levels of substances that break down muscle. In addition, levels of hormones that stimulate muscle growth- estrogen, testosterone, and growth hormone- fall with age.

Then, too, there's disuse. In a particularly insidious twist, the loss of strength from sarcopenia can create a vicious cycle. When it takes a great deal of physical effort to perform daily tasks, people naturally shy away from doing them to avoid discomfort. But since activity, no matter how limited, helps to maintain muscle mass, abandoning one's efforts only serves to speed up muscle loss- creating more weakness still.

But in the problem lies the solution. While you can't completely halt sarcopenia in its tracks, there's much you can do to slow it dramatically and thereby remain nearly as active in your seventies and eighties as much earlier in your life. If you were sedentary as a young adult and in middle age, you can even end up with more muscle mass in later years- and more strength- than you had in your thirties and forties.

Pushing back Sarcopenia While it has been known for decades that strength training-lifting weights and working resistance machines-increases muscle mass and strength in young adults, not 20 years ago, many thought whatever muscle loss occurred in older people was inevitable. Part of the problem was the then prevailing notion that for older people to lift weights was strange, if not downright harmful.

It wasn't helping that the first couple of studies on strength training to stem sacrcopenia had shown just lukewarm results. "Older people didn't respond well," says sarcopenia researcher William Evans, Ph.D., formerly of Tufts and now based at the University of Arkansas for Medical Sciences. "Their muscles didn't get any bigger."

But the reason for the poor results was the very fear that pushing older people too hard , would be bad for them. The studies weren't using the right exercise intensity, Dr. Evans says. Rather, subjects were lifting weights that were too light for them, so their muscles weren't being stimulated to grow. The Tufts researchers then went back and tried strength training in another study, this time using high-intensity workouts in which participants lifted leg weights at levels closer to their maximum capacity. The volunteers, men who ranged in age from 60 to 72, not only completed the regimen safely. They more than doubled their leg strength in just 12 weeks of training.

Other studies on strength training benefits quickly followed. One effort, led by Tufts researcher Maria Fiatarone, M.D., showed that even frail nursing home residents in their nineties could build muscle and strength. Two study volunteers were even able to walk without needing their canes after the eight-week program.

Weightlifting works to build muscle by forcing your body to heal the damage to muscle cells that your efforts create. "At a high enough intensity, you get microscopic tears in muscle," says Dr. Evans. "The muscles rebuild protein, and that makes the cell stronger."

In a typical strength training session, you do six to eight exercises, working muscles in the upper body, lower body, and trunk with moves such as leg lifts and arm curls. You lift against your own "ceiling" weight-wise, progressing to heavier and heavier weights as you go. (An 80-year-old might start out with 2 to 3 lb. weights for each arm or leg and in progress to 10 or 20 lbs. over time).

Talking You into Strength Training

More people take part in aerobic activity for exercise rather than strength training. It's easy to understand why. Incorporating a walk into the day doesn't take much planning, and other aerobic activities like cycling, jogging, or swimming are things you already know how to do and already enjoy. Strength training isn't so familiar-and it takes extra time that has to be set aside rather than folded into your daily routine. But for less than an hour and a half of strength training a week- about 40 minutes a session-you get so much back.

We can't emphasize enough how critical , it is. Aerobic exercise, while it strengthens the heart and lungs isn't sufficient by itself to hold back sarcopenia. A study from Denmark illustrates the point beautifully: men in their late sixties who'd lifted weights regularly for years had muscle mass, similar to that of non-athletes in their twenties. But older runners and swimmers didn't, even though they trained for years, "Running and swimming did not prevent sarcopenia." says Arkansas's Dr. Evans. "Only man who did weights had the younger muscle mass."

Once you get going on a strength training program, you'll quickly see gains from your hard work. "Things are probably happening immediately at the cellular level" when you start, comments Dr. Nelson. In four weeks, you'll get stronger-you can feel yourself take out the trash or carry groceries with more ease. "In four to six weeks, you might see less pain with arthritis."

Strength training also has a synergistic quality to it. Providing not just muscle , but also the vigor that goes with being stronger. It's not surprising when you consider that it can maintain or improve an older persons ability to perform so many activities important to daily life, such as climbing stairs, walking faster, or maintaining balance when on slippery footing. That's especially important for someone who wants to continue living independently.

What's more, building muscle creates a positive cycle in people of any age. The better and stronger you feel, the more likely you are to stay active and do things you enjoy-gardening, playing tennis, and the like. The more active you are, in turn, the more you'll keep weakness at bay.

But preserving your muscle mass is about more than just keeping up a particular level of fitness. It can also impact your ability to withstand disease. When you're sick, the body burns protein faster than usual, pulling protein components from the muscles and delivering them to the immune system, liver, and other organs to use in healing wounds, building antibodies and white blood cells needed to fight illness. If the muscle protein "reservoir" has already been depleted by sarcopenia there's that much less ammunition available.

If you fear you are not in good enough health to strength train, rest assured that it's perfectly safe, even for people with conditions like arthritis or heart disease. You should always get a doctor's OK before beginning any exercise.