After following the progress of 32,269 post-menopausal women for 11 years scientists found that vigorous exercise can reduce the risk of breast cancer by almost a third. It seems that a sedentary lifestyle can be a risk factor for the disease even among the women who are not overweight. Nevertheless activities such as scrubbing floors, chopping wood, digging, fast jogging, tennis, bicycling or dancing are important in order to prevent the disease.

In other words, active women are 30 percent less likely to develop breast cancer than sedentary ones. The findings suggest that exercise itself protects against breast cancer, regardless of whether it leads to weight loss, note Michael F. Leitzmann, MD, and colleagues at the National Cancer Institute.

Lead author Michael Leitzmann from the National Cancer Institute at the US National Institutes of Health said: “In this cohort of postmenopausal women, breast cancer risk reduction appeared to be limited to vigorous forms of activity. It was apparent among normal weight women but not overweight women.”

Not to forget, non-vigorous activity, which included light housework such as vacuuming, washing clothes, painting, general gardening and light sports or exercise, such as walking, hiking, light jogging, recreational tennis, or bowling was not protective.
Breast cancer is the leading cause of cancer deaths among women worldwide, according to the American Cancer Society. The group estimates about 465,000 women died of breast cancer globally in 2007 and 1.3 million new cases were diagnosed.

The study appears in the Oct. 31 online issue of the open-access journal Breast Cancer Research.