(Phoenix, AR) – Women who lift weights twice
a week can prevent or at least slow down “middle-age spread”
and weight gain, a University of Pennsylvania School of
Medicine researcher reported today at the American Heart
Association’s 46th Annual Conference on Cardiovascular Disease
Epidemiology and Prevention.
A study of 164 overweight and obese (body mass index of 25-35) women
between 24 and 44 years of age, found that strength training with
weights dramatically reduced the increase in abdominal fat in pre-menopausal
participants compared to similar women who merely received advice
“On average, women in the middle years of their lives gain
one to two pounds a year and most of this is assumed to be fat,”
said lead author Kathryn H. Schmitz, PhD., Assistant
Professor, Center for Clinical Epidemiology and Biostatistics. “This
study shows that strength training can prevent increases in body
fat percentage and attenuate increases in the fat depot –
or ‘belly fat’ – most closely associated with
heart disease. While an annual weight gain of one to two points
doesn’t sound like much, over 10 to 20 years, the gain is
Women in the two-year weight-training program decreased their body
fat percentage by 3.7 percent, while body fact percentage remained
stable in the controls. The strength-training reduced intra-abdominal
fat, which is more closely associated with heart disease and metabolic
disturbances. More specifically, the women who did strength-training
experienced only a 7 percent increase in intra-abdominal fat compared
to a 21 percent increase in intra-abdominal fat among controls.
The study – dubbed The SHE study, for The Strong, Healthy,
and Empowered – examined whether twice-weekly strength-training
would prevent increases in intra-abdominal and totally body fat
in women who were overweight or obese. The women initially were
separated by baseline percentage body had booster session four times
yearly with certified fitness professionals over two years. The
control fat and age. The strength-training group participated in
supervised strengthening classes for 16 weeks, and group received
a brochure recommending 30 minutes to an hour of exercise most.
days of the week. All of the women were asked not to change their
diets in ways that might lead to weight changes while they were
participating in the study.
The weight-training sessions took about an hour, and the women were
encouraged to steadily increase the amount of weight they lifted.
The weight training included exercises for all major muscle groups,
including the chest, upper back, lower back, shoulders, arms, buttocks
and thighs. The maximal amount of weight women could lift once –
called a one-repetition maximum test – increased by an average
of 7 percent in bench pressing and 13 percent in leg press exercises.
Researchers measured the participants’ body composition with
a dual energy X-ray absorptiometry (DEXA) scan and measurements
of abdominal and total body fat by single slice CT scan at baseline,
and again at one and two years.
“This study showed that strength training is a fairly time
efficient method to prevent the small increases in weight that come
with aging and may increase an adults’ risk for heart disease
and diabetes,” said Schmitz.
The average age of participants was 36 years. Approximately 40 percent
of the sample was non-Caucasian. About two-thirds were college educated
and about half had children under the age of five at home. All had
similar caloric intakes. On average, the women completed 70 percent
of all prescribed exercise sessions over two years.
“There was marginal treatment effects on total fat mass and
subcutaneous abdominal fat,” said Schmitz. “However,
since there was no dietary intervention in this protocol, it’s
not surprising that total body weight and body mass indexes were
Strength training to increase muscle mass has been demonstrated
to allow older persons to delay functional declines associated with
aging. “It can also increase muscle strength to allow aerobic
activity in overweight people,” adds Schmitz. “Making
women stronger and more confident behaviorally, may serve as a gateway
to getting overweight women to be more active.”
For her research, Schmitz will be awarded the 2006 Trudy Bush Fellowship
for Cardiovascular Research in Women’s Health from the American
health Association’s Council on Epidemiology and Prevention.
The National Institutes of health funded the study, which was co-authored
by Peter J. Hannan, Michael D. Jensen, MD, and MStat.
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