The study, conducted by Paul Williams of the U.S. Department
of Energy’s Lawrence Berkeley National Laboratory (Berkeley
Lab), followed 6,119 men and 2,221 women who maintained their
weekly running mileage (to within three miles per week) over
a seven-year period. On average, the men and women who ran
over 30 miles per week gained half the weight of those who
ran less than 15 miles per week.
“To my knowledge, this is the only study of its type,”
says Williams, a staff scientist in Berkeley Lab’s Life
Sciences Division. “Other studies have tracked exercise
over time, but the majority of people will have changed their
exercise habits considerably.”
The research is the latest report from the National Runners'
Health Study, a 20-year research initiative started by Williams
that includes more than 120,000 runners. It appears in the
May 3 issue of the journal Medicine and Science in Sports
Specifically, between the time subjects entered the study
and when they were re-contacted seven years later, 25-to-34-year-old
men gained 1.4 pounds annually if they ran less than 15 miles
per week. In addition, male runners gained 0.8 pounds annually
if they ran between 15 and 30 miles per week, and 0.6 pounds
annually if they ran more than 30 miles per week.
This trend is mirrored in women. Women between the ages of
18 and 25 gained about two pounds annually if they ran less
than 15 miles per week, 1.4 pounds annually if they ran 15
to 30 miles per week, and slightly more than three-quarters
of a pound annually if they ran more than 30 miles per week.
Other benefits to running more miles each week included fewer
inches gained around the waist in both men and women, and
fewer added inches to the hips in women.
“As these runners aged, the benefits of exercise were
not in the changes they saw in their bodies, but how they
didn’t change like the people around them,” says
Although growing older and gaining weight is something of
a package deal, it isn’t the same in everyone. The lucky
few remain lean as they age, most people pack on several pounds,
and some people become obese. The latter group is particularly
at risk for high blood pressure, high cholesterol, and diabetes.
Fortunately, Williams’ results show that maintaining
exercise can combat such extreme weight gain.
“Getting people to commit to a vigorously active lifestyle
while young and lean will go a long way to reducing the obesity
epidemic in this country,” says Williams.
Another paper published in the November 2006 issue of the
journal Obesity by Williams and Paul Thompson of
Hartford (CT) Hospital found that runners who increased their
running mileage gained less weight than those who remained
sedentary, and runners that quit running became fatter.
“The time to think about exercise is before you think
you need it,” says Williams. “The medical journals
are full of reports on how difficult it is to regain the slenderness
of youth. The trick is not to get fat.”
Williams’ research was funded by the National Heart,
Lung and Blood Institute. The May 3 paper in the journal Medicine
and Science in Sports and Exercise is entitled Maintaining
Vigorous Activity Attenuates 7-yr Weight Gain in 8,340 Runners.