Moderate Exercise Cuts Women's Risk of Gallstone Surgery
Sept. 9, 1999 (Seattle) -- A few hours of brisk walking, jogging, or
bicycling each week can reduce a woman's risk for gallstone surgery, according
to a study in the Sept. 9 New England Journal of Medicine. But the study
shows that exercise alone doesn't seem to help women who are severely
Researchers at the Harvard School of Public Health found that women who
exercised at least two-and-a-half hours a week were about 30% less likely to
need surgery for gallstones than women who didn't exercise. The researchers
also reported that women who spent more than 41 hours a week sitting at work or
in their cars were about 40% more likely to have gallstone surgery than women
who spent fewer than six hours sitting.
"Essentially, we found yet another advantage of exercise," says
Michael Leitzmann, MD, one of the study's authors. Leitzmann tells WebMD that
although the results probably apply to men too, they are especially important
for women, who are more likely than men to get gallstone disease.
One encouraging finding is that almost any type of exercise helps, Leitzmann
says. "Protection was conferred not only by vigorous exercise activities,
such as jogging, running, racket sports, and brisk walking, but also by
nonvigorous activities, such as stair climbing," he says. Leitzmann says
the benefits of exercise increased up to about five hours a week, then reached
a plateau, suggesting that women don't need to engage in strenuous activities
to protect themselves.
The study also found that women who were severely overweight did not benefit
directly from exercise, says David Johnston, MD, a researcher at the University
of New Mexico who wrote an editorial that accompanied the Harvard study.
Johnston tells WebMD that exercise may have helped these women to lose weight
and keep it off, which is one way to lower the risk of gallbladder disease. But
exercise without weight loss didn't help, he says.
The study was conducted by looking at the health records of over 60,000
female nurses over a 10-year period. During that time, approximately 3,300 of
the women had surgery for gallstone disease. The disease can cause severe
abdominal pain and a variety of digestive problems.
Johnston says the Harvard study, along with earlier studies of men, provide
very strong evidence that exercise can help many people avoid gallbladder
surgery. But he says scientists still aren't sure why exercise helps.
"This study didn't answer that question," Johnston says, adding that
one possibility is that exercise reduces the amount of cholesterol in bile, the
fluid that fills the gallbladder. That would make a difference because most
gallstones are formed from cholesterol, he tells WebMD. Another possibility, he
says, is that exercise sends a signal to the gallbladder to contract, which
allows it to expel stones before they cause problems.
But whatever the explanation, Johnston says, "The important thing is
that we know now that exercise works and that you don't have to be a super
athlete to reduce your risk of gallbladder surgery."