Exercise May Offer Protection Against Breast Cancer

Past research showed that female college athletes had a much lower risk of breast cancer than their inactive peers. The conclusion: Something about exercise may stave off this deadly disease.

Now, research suggests that all women—not just former athletes— can reduce their breast cancer risk with exercise. Some studies say that it is the amount of exercise a woman averages across her lifetime that matters. But even women who do not begin exercising until they are older seem to lower their risk.

How much exercise is enough? Women age 40 and younger who averaged four hours of exercise a week cut their risk by 50 percent compared to less active women. But women who only exercised two hours a week also had a lower risk compared to inactive women.

The latest guidelines from the American Cancer Society emphasize moderate to vigorous exercise five or more days per week. Forty-five to 60 minutes of physical activity each day is the preferred amount, but even just 30 minutes may help reduce risk.