Reducing Your Risk — Exercise

Studies of athletic women have shown that they have lower rates of breast and other cancers when compared to women who are less active. The minimum amount of moderate to vigorous activity that produces a reduction in breast cancer rates seems to be around 4 hours per week. ref Exercise lowers risk primarily by decreasing a woman’s exposure to estrogen. Active women tend to have fewer periods, a later menarche, earlier menopause and lower amounts of body fat.

All women can decrease their chances of breast cancer by at least 30%, by exercising 4 hours per week intensely enough to work up a sweat. ref

You'll find more information about exercise and cancer prevention, on the Health Canada website: Workshop Report: Physical Activity and Cancer Prevention