If you do shift work, and frequently work at night when the rest of the world is sleeping, you may be putting yourself at a higher risk for breast cancer. The World Health Organization has found enough cause to list ultraviolet light during sleep as a "probable carcinogen," putting it in the same category as toxic chemicals such as PCB's (polychlorinated biphenyls).

Exercise reduces the risk of breast cancer for all women at all risk levels, even exercise programs begun after menopause. A study conducted by researchers at Fred Hutchinson Cancer Research Center found that the activity does not have to be strenuous, but it should be consistent to obtain the maximum benefit.