Irregular Exercise Pattern May Add Pounds
consequences of quitting exercise may be greater than previously
thought, according to a new study from the U.S. Department of
Energy’s Lawrence Berkeley National Laboratory that determined
that the weight gained during an exercise hiatus can be tough to shed
when exercise is resumed at a later date.
conducted by Paul Williams of Berkeley Lab’s Life Sciences
Division, found that the key to staying trim is to remain active
year-round, year-after-year, and to avoid seasonal and irregular
exercise patterns. Most of all, don’t quit. Failure to do so may
be a contributing factor in the nation’s obesity epidemic.
"The price to
pay for quitting exercise is higher than expected, and this price may
be an important factor in the obesity epidemic affecting Americans,"
says Williams, whose study is published in the journal Medicine &
Science in Sports and Exercise.
should prompt people to think twice before taking a break from their
exercise regimens, despite the pressures of family and work
obligations, or waning motivation.
collected from the National Runners’ Health Study, Williams found
that the impacts of increasing and decreasing vigorous exercise
aren’t the same among all runners. At distances above 20 miles
per week in men and 10 miles per week in women, the pounds gained by
running less were about the same as the pounds lost by running more. At
these exercise levels, the effects of training and quitting training
are comparable, and the weight gains and losses associated withchanges
in exercise levels are probably reversible.
Williams found that people who didn’t run as many miles per week
face an uphill battle if they want to lose the pounds accumulated
during an exercise hiatus. At these less intense levels, an
interruption in exercise produces weight gain that is not lost by
simply resuming the same exercise regimen.
mileages, there is asymmetric weight gain and loss from increasing and
decreasing exercise, leading to an expected weight gain from an
exercise hiatus," says Williams. "In other words, if you stop
exercising, you don’t get to resume where you left off if you
want to lose weight."
Williams compared 17,280 men and 5,970 women who decreased their
running distance with 4,632 men and 1,953 women who increased their
running distance over a 7.7-year period. He found that runners who
decreased their distance from five to zero miles per week gained four
times as much weight as those who decreased their distance from 25 to
20 miles per week. He also found that people who started running after
an exercise layoff didn’t lose weight until their mileage
exceeded 20 miles per week in men, and 10 miles per week in women.
his findings suggest that an effective public health policy for
preventing weight gain may need to include a strategy to keep
physically active people active. His study also underscores the
importance of avoiding start-stop exercise patterns. Exercise designed
to prevent obesity may fall short of its benefits if the exercise is
irregular, seasonal, or often interrupted.
getting fat because we don’t exercise sufficiently and
consistently. The real solution to the obesity epidemic is getting
people to exercise before they think they need it, and to stick with
it," says Williams. "The ounce of prevention is indeed worth a pound of
A study by
Williams published in the same journal in August, 2007, revealed that
middle-age weight gain is reduced by one-half in runners who ran 30 or
more miles per week, compared to runners who ran less than 15 miles per
week. These results, in conjunction with this more recent study,
suggest a new way of tackling the obesity problem.
scientists attribute the obesity epidemic to excess calories rather
than exercise, because dieting has been shown to produce more weight
loss than exercise," says Williams. "My findings suggest that calorie
intake and body weight may be self regulating in active individuals."
"Asymmetric Weight Gain and Loss From Increasing and Decreasing
Exercise" was published in the February 2008 issue of the journal
Medicine & Science in Sports and Exercise. It was supported in part
by grants from the National Heart Lung and Blood Institute.
For more information on the DOE/Lawrence Berkeley National Laboratory, visit www.lbl.gov.