In the United States, breast cancer affects about one in eight women over the course of their lifetime. Breast cancer is a cancer that starts in the tissues of the breast and is either diagnosed as ductal carcinoma or lobular carcinoma. Most breast cancers are ductal carcinoma, which starts in the ducts, rather than the lobules, where lobular carcinoma originates. Depending on how early it is detected, most forms of breast cancer are treatable and not fatal. While it is not as common, men can develop breast cancer as well.1
A recent analysis conducted by researchers at the University of North Carolina at Chapel Hill revealed that either mild or intense exercise before or after menopause may reduce breast cancer risk. However, significant weight gain may negate the possibility of prevention. This study was published in Cancer, which is a peer-reviewed journal of the American Cancer Society.2
The recent study conducted at UNC included 1,504 women who had breast cancer (233 noninvasive and 1,271 invasive) and 1,555 women without breast cancer. The ages of the women ranged from 20 to 98 years old. This study was part of the Long Island Breast Cancer Study Project, which is an investigation of possible environmental causes of breast cancer.3
The results of the study indicated that the women who exercised, regardless of the phase of life they were in, had a reduced risk of developing breast cancer. Those who exercised 10 to 19 hours per week benefited the most, and saw about a 30% reduced risk in developing cancer.4
Lauren McCullough, who led the study and is a doctoral candidate at the UNC Gillings School of Public Health, stated, “The observation of a reduced risk of breast cancer for women who engaged in exercise after menopause is particularly encouraging given the late age of onset for breast cancer.”5
Even though it was discovered exercise reduces the risk of breast cancer, the extent and duration of the exercise required to reap these benefits is still not known. It is also unknown whether or not women with certain body types experience a reduced risk when they exercise, and if exercise reduces the risk of all types of breast cancer.6
Additionally, the results of the study indicated women who were active yet experienced a significant amount of weight gain, especially after menopause, had an increased risk of developing breast cancer. This indicates that the cancer-reducing risk benefits of exercise are nullified if a healthy weight maintenance protocol is not followed.7
