Americans know that regular physical activity improves health,*
yet only about one-fifth of the population is active enough to
derive health benefits from it, according to the Surgeon Generals
1996 report on physical activity and health.
While the benefits of regular physical activity are well documented,
few studies have compared the effects of different types of physical
activity. However, two randomized clinical trials reported in
the Journal of the American Medical Association January
27, 1999, show that lifestyle activities and structured exercise
can result in similar improvements in fitness.
The studies measured fitness in terms of maximal oxygen uptake,
reduced blood pressure, and reduced body fat. In one study, conducted
by Andrea Dunn, Ph.D., of the Cooper Institute for Aerobics Research,
et al., 235 moderately overweight, sedentary men and women between
the ages of 35 and 60 participated. They were divided into two
groups and placed in either a lifestyle activity or a structured
activity program consisting of 6 months of intensive intervention
and 18 months of maintenance intervention. Individuals in the
structured activity group did aerobic exercises for 20-60 minutes
5 days per week. Participants in the lifestyle activity group
practiced cognitive and behavioral strategies to help them accumulate
at least 30 minutes per day of moderate-intensity physical activity.
After 6 months, the structured exercise group had increased their
cardiorespiratory fitness nearly two times more than that of the
lifestyle group, but at the end of 24 months, the two groups
cardiorespiratory fitness levels were similar. Both groups also
had similar significant improvements in diastolic blood pressure,
percentage of body fat, and ratio of total cholesterol level to
high-density lipoprotein cholesterol level at the end of 6 months
and 24 months. In the 18-month followup, both groups physical
activity and cardiorespiratory fitness levels declined. However,
there was a greater decline in fitness and a greater increase
in weight in the structured exercise group, suggesting that the
physical activity routines of this group were not maintained as
effectively as those of the lifestyle group.
*According
to the 1994 - 96 Diet and Health Knowledge Survey.