The New York Times
recently reported on emerging research indicating that walking may
help to lower breast cancer risk. Two studies in Cancer
Epidemiology, Biomarkers & Prevention assessed the way that
female bodies process estrogen and the role that exercise plays. The
first study involved two decades of follow-up with approximately 74,000
postmenopausal women aged 50 to 73 in the American Cancer Society’s
Epidemiology and Research Program. All the women were asked about
their exercise habits in biannual questionnaires. The most common
form of exercise was easy, inexpensive, and required no gym
membership: walking. As it turns out, those women who walked for at
least seven hours a week had a 14% lower risk of developing breast
cancer than those women who walked for less than three hours a week.
More vigorous or longer periods of exercise per week resulted in
greater benefits and further reduced women’s risk.
The second study examined several hundred sedentary premenopausal
women in hopes of determining how exercise might contribute to
lowered risk of developing breast cancer. The women were split into
two cohorts, one of which continued with previous sedentary lifestyles while the other group was put on a moderate exercise regimen for four
months. Urine samples measuring a number of estrogen metabolites were
compared for women at the beginning of the trial and after four
months had passed. The ratio of estrogen metabolites in exercising
women shifted in such a way that suggested a decreased risk of
cancer. It appears that by reducing total body fat and altering the
body’s production of estrogen metabolites, exercise plays a
physiological role in reducing breast cancer risk by making it harder
for the cancer to gain an initial foothold. Although statistics are
not infallible, and exercise has not been shown to prevent breast
cancer absolutely, the reduction in risk is significant. When walking
is such an accessible activity and the
general health benefits of frequent exercise are already an
established fact, why not be hopeful about the potential for cancer
reduction as well?
Reference: Reynolds, Gretchen. "How Walking May Lower Breast Cancer Risk." NY Times Well. NY Times, 9 Oct. 2013. Web. 10 Oct. 2013.
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