Physically Active, Lean Women Have
the Lowest Mortality
December 23, 2004
By Harvard School of Public Health
New research findings from the Department of Nutrition
at the Harvard School of Public Health and Brigham and
Women's Hospital show that increased body fatness measured
by body-mass index (BMI) and reduced physical activity
are both strong and independent predictors of premature
death in women. The study appears in the December 23,
2004 issue of the New England Journal of Medicine.
Body-mass index is determined by dividing an individuals'
weight in kilograms by the square of height in meters.
For non-metric, weight in pounds is divided by the square
of height in inches, then multiplied by 703. A BMI over
25 is considered overweight. Approximately two thirds
of Americans are classified as overweight or obese.
More than 115,000 participants who were free of cardiovascular
disease or cancer, between the ages of 30 and 55 and
had filled out biennial health and lifestyle questionnaires
between 1976 and 2000 were chosen for the study from
the Brigham and Women's Hospital-based Nurses' Health
Study. In the questionnaires the women were asked to
report on average how much time was spent per week on
moderate physical activities such as brisk walking,
and vigorous physical activities, among them, jogging,
running, bicycling, playing tennis and swimming laps.
Women who spent 3.5 hours per week or more exercising
were considered physically active.
The researchers found that both obesity and physical
activity significantly and independently affected mortality.
A high level of physical activity did not eliminate
the risk of premature death associated with obesity
and leanness did not counteract the increased risk in
mortality conferred by inactivity. Compared to physically
active, lean women, there was nearly a two and half-fold
increase in risk of death for inactive and obese women.
The researchers estimated that excess weight (BMI over
25) and physical inactivity (less than 3.5 hours per
week) accounted for 31 percent of all premature deaths
among the study participants with 59 percent of the
deaths attributable to cardiovascular disease and 21
percent from cancer among the non-smoking women. During
the 24 year span of the study, 10,282 deaths occurred;
2,370 from cardiovascular disease, 5,223 from cancer
and 2,689 from other causes.
"It is clear that both weight and exercise are
important for health and longevity," said Frank
Hu, lead author of the study and an associate professor
of nutrition and epidemiology at the Harvard School
of Public Health. "There is no question that one
should be as active as possible no matter what your
weight is, but it is equally important to maintain a
healthy weight and prevent weight gain through diet
and lifestyle."
Funding for the study was provided by grants from the
National Institutes of Health.
Source:www.yubanet.com
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