When it comes to breast cancer, the information about treatment has been plentiful, but when it comes to prevention – what are some key things women should do to protect themselves while they are healthy?

A new study by the University of North Carolina Gillings School of Global Public Health, in Chapel Hill, N.C. found that it can be as simple as doing a bit of exercise.

The study noted that women who exercised cut their risk of breast cancer by as much as 30 percent. Weight gain, however, may undermine the benefit of exercise, according to the study published in the June 25 online edition of Cancer.

For the study, researchers collected data on more than 1,500 women with breast cancer and a similar number of women without the disease. All the women had taken part in the Long Island Breast Cancer Study Project.

They found women who exercised before or after menopause had a reduced risk of breast cancer. Women who exercised 10 to 19 hours a week had the largest benefit — about a 30 percent reduced risk.

The risk of breast cancer was cut with any amount of exercise, the study found. The risk reduction was seen mostly for hormone receptor-positive breast cancer, which is the most commonly diagnosed type among American women.

Even among active women, however, gaining a significant amount of weight, particularly after menopause, increased the risk of breast cancer, negating the beneficial effect of exercise, the researchers found.

If you are a woman looking to stay healthy, stay active.