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
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
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
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
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.