A large study which was published in Cancer Epidemiology, Biomarkers, and Prevention found that moderate physical activity helped to lower the breast cancer risk of postmenopausal women by 14%, while higher levels of physical activity helped to lower the risk by 25%; these were compared to women with the lowest levels of physical activity.
Researchers from the American Cancer Society looked at the data of 73,615 postmenopausal women who were part of the CPS-II Nutrition Cohort, a prospective study on cancer which had began in 1992 and ran for 17 years.
The group of women in the study who carried out the most physical activity were found to have a 25% lower breast cancer risk than the least active group. This figure was largely consistent with much previous research.
What was significant was that even those whose only form of physical activity was walking exhibited some benefit – the researchers found that the women who walked at least 7 hours each week had a 14% lower breast cancer risk than those who only walked 3 hours or less each week. That was after taking into account body mass index (BMI), hormone receptor status, postmenopausal hormone use, and weight gain.
This study has revealed that just an average of one hour of walking every day helped to lower breast cancer risk. That would not be too difficult for most women.
And, for the study, the physically active women mostly took part in moderate intensity exercises such as walking, aerobics, dancing and cycling. It follows that those who actually take part in more intense exercises such as running, tennis and swimming would experience even lower risk of cancer.
“Our results clearly support an association between physical activity and postmenopausal breast cancer, with more vigorous activity having a stronger effect. Our findings are particularly relevant, as people struggle with conflicting information about how much activity they need to stay healthy. Without any other recreational physical activities, walking on average of at least one hour per day was associated with a modestly lower risk of breast cancer. More strenuous and longer activities lowered the risk even more,” said Alpa Patel, Ph.D, the leader of the study.