At age 75, would a senior Popeye still be able to
take on Bluto?
New study finds tools to better identify senior
citizens at risk of functional decline; design programs building
resistance and power
Aug. 14, 2013 - If Popeye were to age naturally
like the rest of us, he would need more than just big muscles to stay
independent during his senior years. When it comes to muscles and aging,
the important thing is quality, not quantity, as shown by the findings
of new study.
Published in the Journal of the American Medical
Directors Association, the study looked at the relationship between
functional independence and muscle mass and quality in 1219 healthy
women aged 75 and older. It was by Mylène Aubertin-Leheudre, PhD, a
researcher at the Research Centre of the Institut universitaire de
gériatrie de Montréal, affiliated with
Université de Montréal.
It should be noted, the researchers say, that these
results are applicable to men's health as well.
This study consisted in analyzing the biometric
data of the women. The researchers assessed body composition, handgrip
and knee extension strength. Physical functions were measured with the
chair stand test and gait speed test (usual and fast).
Participants also had to indicate whether they
experienced difficulty performing functional tasks. Independently of
muscle mass, participants with high muscle quality had low risks of
functional impairment, whereas people with high muscle mass but low
muscle quality had high risks of impairment.
The analysis showed that women who maintained
better muscle quality (the ratio of strength to muscle mass) also had
better functional reserves, which help people maintain independence.
Women with lower muscle quality had a three to six times higher risk of
developing functional impairments (e.g., difficulty walking, getting up
from a chair, or climbing stairs).
“These results contradict what has been believed
for a long time about muscles and aging. Many seniors, whom we often
perceive as frail and fragile, can surprise us by their muscle strength.
Although inevitable, age-related muscle loss (a normal process called “sarcopenia”
- see below)
should no longer be seen as a sign of weakness,” stated Aubertin-Leheudre.
She hopes that these findings will give health care
professionals tools to better identify seniors at risk of functional
decline and to design physical activity programs that would specifically
target resistance and power and not simply a gain in muscle mass. Popeye
should take heed!
Decreased physical activity with aging appears to be the
key factor involved in producing sarcopenia
Sarcopenia is a term
utilized to define the loss of muscle mass and strength that
occurs with aging. Sarcopenia is believed to play a major
role in the pathogenesis of frailty and functional
impairment that occurs with old age. Progressive muscle
wasting occurs with aging.
The prevalence of
clinically significant sarcopenia is estimated to range from
8.8% in young old women to 17.5% in old old men. Persons who
are obese and sarcopenic (the "fat frail") have worse
outcomes than those who are sarcopenic and non-obese.
There is a
disproportionate atrophy of type IIa muscle fibers with
aging. There is also evidence of an age-related decrease in
the synthesis rate of myosin heavy chain proteins, the major
anabolic protein. Motor units innervating muscle decline
with aging, and there is increased irregularity of muscle
unit firing. There are indications that cytokines-especially
interleukin-1beta, tumor necrosis factor-alpha, and
interleukin-6-play a role in the pathogenesis of sarcopenia.
Similarly, the decline in
anabolic hormones-namely, testosterone,
dehydroepiandrosterone growth hormone, and insulin-like
growth factor-I-is also implicated in the sarcopenic
The role of the
physiologic anorexia of aging remains to be determined.
Decreased physical activity with aging appears to be the key
factor involved in producing sarcopenia. An increased
research emphasis on the factors involved in the
pathogenesis of sarcopenia is needed.