A study of 1,700 relatively healthy residents of Rancho Bernardo, Calif.,
found that 6 percent had reduced muscle mass and strength, a condition
known as sarcopenia. However, the prevalence rose dramatically as people
aged. Only 4 percent of men and 3 percent of women aged 70 to 75 had sarcopenia,
but 16 percent of men and 13 percent of women aged 85 or older were affected,
according to authors Elizabeth Barrett-Connor, M.D., Edward M. Castillo,
Ph.D., and colleagues from the University of California, San Diego.
While Rancho Bernardo is a middle-class community in a temperate climate,
Barrett-Conner says that the prevalence of sarcopenia is similar to that
in a representative sample of the general U.S. population.
Both men and women with sarcopenia were significantly older than those
without it, says Barrett-Connor, meaning that age itself was a risk factor.
They also lost more than muscle; they had less fat and a lower body mass
index (a measure of body size, combining height and weight).
Men with sarcopenia were more likely to have fallen within the previous
12 months than other men. Women who smoked were more likely to have sarcopenia,
while women who exercised at least three times a week were less likely
to be affected.
Research on sarcopenia has been limited and Barrett-Connor says that little
is known about its origins or prevention. Advancing age brings with it
hormonal, neurological, metabolic and behavioral changes. Any of these
might affect muscle mass.
One intervention, strength-training programs, has proven to be a “safe
and effective means by which to improve physical capabilities, reduce risk
for falls, prevent functional limitations and avert the development of
certain chronic diseases or their symptoms in older adults,” says
Miriam E. Nelson, Ph.D., of the Friedman School of Nutrition Science
and Policy at Tufts University, in another report.
Strength training uses weights of some kind — machines, dumbbells,
ankle or wrist weights — to create resistance which helps build
muscle mass.
After reviewing 17 strength training studies among older persons, Nelson
says that some advantages are clear.
“The benefits of strength training include increased muscle and
bone mass, muscle strength, flexibility, dynamic balance, self-confidence
and self-esteem,” she says. “Strength training also helps
reduce the symptoms of various chronic diseases such as arthritis, depression,
type 2 diabetes, osteoporosis, sleep disorders and heart disease, and,
when combined with balance training, reduces falls.”
The research is not clear on whether the benefits of strength training
can actually delay the onset of disability, or on how such training helps
the elderly. The benefit might come from increased muscular strength, reducing
the burden of chronic disease or simply maintaining the strength to carry
on the tasks of everyday living. Frequency and intensity of strength training
are also open questions, although the American College of Sports Medicine
recommends two to three days per week of strength training, a schedule
which is appropriate for the elderly, Nelson says.
“The key challenges as this field of exercise science moves forward
are to best identify the most appropriate strength-training recommendations
for older adults and to greatly increase the access to safe and effective
programs in a variety of settings,” she concludes.
Barrett-Connor’s work was supported by the National Institute on
Aging and the National Institute of Diabetes and Digestive and Kidney Diseases.
Nelson’s project was supported by the U.S. Department of Agriculture.
