More and more research is finding that exercise and other lifestyle factors can reduce your risk of cancer. Among women, new research found that exercise can reduce your risk of breast cancer by up to 30%. However, weight gain, even in the presence of exercise increased the risk of breast cancer.
We don’t know why exercise is linked with a reduced risk, but it is thought that a reduction in body fat results in less exposure to circulating hormones, growth factors and pro-inflammatory markers, all of which are associated with breast cancer risk, said study authors.
Exercise also improves other mechanisms that may affect cancer risk including enhanced immune response, antioxidant capacity and DNA repair.
In the study, any amount of exercise reduced the risk of breast cancer, but women that exercised from 10-19 hours a week had the greatest risk reduction--about 30%.
Furthermore, age didn’t matter, women who exercised before or after menopause had a reduced risk of breast cancer. This is particularly encouraging as breast cancer is more common in post-menopausal women.
The risk reduction was greatest for hormone receptor-positive breast cancer, the most common form of breast cancer.
With all the good news about exercise, there was one caveat in the findings. Even among active women, gaining a significant amount of weight, particularly after menopause, increased the risk of breast cancer, negating the beneficial effect of exercise.