Daily Walk May Cut Your Breast Cancer Risk10/04/13
FRIDAY, Oct. 4 (HealthDay News) -- Older women who walk every
day may reduce their risk of developing breast cancer. And those
who exercise vigorously may get even more protection, according to
The study of more than 73,000 postmenopausal women found that
walking at a moderate pace for an hour a day was associated with a
14 percent reduced breast cancer risk, compared to leading a
sedentary lifestyle. An hour or more of daily strenuous physical
activity was associated with a 25 percent reduced risk, the study
This is welcome news for women who aren't very athletic.
"The nice message here is, you don't have to go out and run a marathon to lower your breast cancer risk," said study researcher Alpa Patel, senior epidemiologist at the American Cancer Society, which funded the study.
"Go for a nice, leisurely walk an hour a day to lower risk," Patel advised.
Breast cancer is the leading cancer among women. In the United
States, about one in eight women will develop the disease in her
The women who reported moderate exercise walked about three
miles an hour, or about a 20-minute mile. The more vigorous
exercisers participated in such activities as fast walking -- about
4.5 miles in an hour, the equivalent of a light jog, Patel said --
moderate cycling or lap swimming.
For the study, published online Oct. 4 in
Cancer Epidemiology, Biomarkers & Prevention, Patel and
her team identified more than 73,000 women past menopause who were
enrolled in an American Cancer Society study on cancer
When they enrolled in 1992, the average age was nearly 63. The
women completed a questionnaire about medical, environmental and
demographic factors at the start and repeated the reports every two
years between 1997 and 2009. The study participants also reported
on their physical activity and time spent sitting, including
watching television and reading, and reported any diagnosis of
During the follow-up, which was roughly 14 years, 4,760 women
developed breast cancer.
The researchers compared the exercise habits of women who
developed breast cancer and those who did not. About 9 percent
never participated in physical activity, while about half reported
walking as their sole activity.
Those who walked seven hours or more a week, even without
engaging in other recreational physical activity, reaped protective
benefits compared to those who walked three hours or less a
The message is encouraging, Patel said.
However, the study only found an association between moderate
exercise and reduced breast cancer risk, not a direct
While other studies have found that exercise lowered risk of
breast cancer more for women with a lower body mass index (BMI) --
a calculation of body fat based on height and weight -- this study
found the effect held regardless of BMI, weight gain in adulthood
or use of postmenopausal hormone therapy.
Other studies have found a link between time spent sitting and
breast cancer risk, but Patel's group did not find this link.
This is "a good news study for women," said another cancer
expert, Dr. Laura Kruper, who was not involved with the
The findings add to the accumulating evidence about exercise
lowering breast cancer risk, and present a goal that is reachable
for most women, said Kruper, co-director of the breast cancer
program at the City of Hope Cancer Center in Duarte, Calif.
"This is something nearly every woman can do," Kruper said of exercising moderately for an hour daily.
"This is not running a marathon," she said.
Her advice to sedentary women who want to reduce their breast
cancer risk: "If you get off the couch and walk around, it would
Why does exercise appear to lower breast cancer risk? The
mechanism is mostly hormonal, Patel said. Breast cancer risk is
affected by lifetime exposure to estrogen, with more exposure
increasing risk. Older, physically active women have lower levels
of estrogen than their sedentary peers.
Besides exercising, women who want to reduce breast cancer risk
should maintain a healthy body weight, Patel said, and if they
drink, they should limit alcoholic beverages to no more than one
To learn more about risk factors for breast cancer, visit the
American Cancer Society.
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