Older People Who Diet Without Exercise Lose Muscle
Mass Needed for Daily Activities
People tend to lose muscle mass as they age but too
much may interfere with daily activities
Sept.
17, 2008 − A study using inactive overweight older people has found that
those in an exercise program for four months became more fit and burned
off more fat than those who only relied on a diet.
The new study also showed that when older people
diet without exercising, they lose more lean muscle compared to those
who exercise, said senior researcher Bret H. Goodpaster.
When they combined weight loss with exercise, it
nearly completely prevented the loss of lean muscle mass. The results
are important because older people tend to lose muscle mass as they age
and too much muscle loss may interfere with activities of daily living.
The study, Separate and combined effects of
exercise training and weight loss on exercise efficiency and substrate
oxidation, appears in the current issue of the Journal of Applied
Physiology, published by The American Physiological Society. Francesca
Amati, John J. Dube, Chris Shay and Goodpaster, all of the University of
Pittsburgh, carried out the study.
Study looks at exercise efficiency
The researchers wanted to know the best way to get
better (more efficient) at completing a defined exercise task. In
particular, they wanted to know if greater fitness could be achieved
through exercise training, weight loss (through dieting), or both. In
addition, they wanted to know which fuel source the body would draw
upon, carbohydrates or fats, under these different conditions.
The 64 participants were 60-75 years of age and
were either overweight or obese. All of the participants were sedentary
at the outset of the study. The researchers divided the participants
into three groups:
● exercise only
● diet only
● exercise plus diet
Those who exercised could either walk on a
treadmill or ride a stationary bicycle, although most chose to walk. The
dieters reduced their caloric intake to achieve a 10% weight loss by the
end of the four-month study period. The final group combined both the
daily exercise and the diet.
TODAY'S News for senior citizens, baby boomers
Exercise increases efficiency, burns more fat
The researchers measured how many calories the
participants expended during a set work load on a stationary bicycle at
the beginning and at the end of the experiment.
They found that the:
● Exercise group expended fewer calories (became
more efficient) on the exercise task at the end of the study compared to
the beginning.
● Exercise group drew more on fat stores as the
source of their bodys fuel.
● Diet-only group did not gain efficiency in
performing the exercise task, even though they weighed less at the end
of the experiment.
● Diet-only groups weight loss resulted from a
loss of both muscle and fat.
● Exercise plus diet group was the most efficient
at the exercise task at the end of the experiment. This shows an
additive effect of both dieting and exercise, but most of that benefit
was due to exercise.
● Exercise plus diet group, like the
exercise-only group, drew more on fat stores as an energy source.
The take-home message is that, even among older
people and during a fairly short period of time, exercise produces
metabolic changes that require the expenditure of fewer calories during
physical activity, Goodpaster said. Exercise also allowed older people
to more preferentially burn fat, which may be healthier metabolically.
Information provided by source:
Physiology is the study of how molecules, cells,
tissues and organs function to create health or disease. The American
Physiological Society (www.The-APS.org/press) has been an integral part
of this discovery process since it was established in 1887
Sept.
17, 2008 − A study using inactive overweight older people has found that
those in an exercise program for four months became more fit and burned
off more fat than those who only relied on a diet.
Aug.
5, 2008