Daily Hour Walk Lowers Breast Cancer Risk
A new study attempting to better understand the link between physical activity and lower postmenopausal breast cancer risk has found that walking for an hour a day reduces a woman’s risk, regardless ofweight, hormone use or other factors linked with risk. The study was published in Cancer Epidemiology, Biomarkers & Prevention.
Study researchers gathered data from almost 74,000 women who were ages 50 to 74 when they enrolled 19 to 20 years ago. At the start, the women answered questions about their activity habits, weight, hormone use and other risk factors. They updated the information periodically until the study ended in 2009. By that time, 4,760 women were diagnosed with breast cancer.
Almost one of every ten women reported they were not active at all. Almost half said walking was their only recreational activity.
The authors translated the women’s tennis, jogging and other activities into metabolic equivalent, or METs, a measure for how much energy your body uses for the activity. Women who were the most active – those with at least 42 MET hours per week – had a 25 percent lower risk for breast cancer compared with the least active, women with less than seven MET hours per week. A woman in the highest MET group would be jogging about an hour a day, for example.
When looking at the women who only walked, walking for seven hours or more per week linked to a 14 percent lower risk for breast cancer, compared with those who walked for three hours or less.
The link to lower risk applied to both estrogen-receptor positive (ER+) and negative (ER-) breast cancers. The lower risk remained the same among women who were overweight or obese, and those who had gained weight as adults — at least 35 pounds. AICR’s report and its continuous updates found that both of these factors increase postmenopausal breast cancer risk. The link also held among women who had taken postmenopausal hormones, other factors linked with increased risk.
Janet S. Hildebrand, et al. "Recreational Physical Activity and Leisure-Time Sitting in Relation to Postmenopausal Breast Cancer Risk." Cancer Epidemiol Biomarkers Prev. October 2013, 22; 1906.