Walk at least three times a week—and keep it up if you’re diagnosed with breast cancer.

Exercise can prevent breast cancer, or help you beat the disease.

RODALE NEWS, EMMAUS, PA—Women who get active after being diagnosed with breast cancer have a 45 percent greater chance of survival than those who sit around most of the time, according to a study published in the Journal of Clinical Oncology. Women who exercised in the year before being diagnosed were also 30 percent more likely to survive, compared to women who were inactive leading up their diagnosis. The latest study joins two decades of research that links exercise to breast cancer risk reduction or greater survival rates.

THE DETAILS: Yale researchers studied 933 women, ages 18 to 64, who were enrolled in the Health, Eating, Activity, and Lifestyle (HEAL) study. The women were diagnosed with breast cancer between 1995 and 1998; researchers followed their progress though September 2004. Not only were women more likely to survive if they exercised, active women who lowered their physical activity levels after being diagnosed had a four-fold greater chance of dying than inactive women who stayed sedentary after diagnosis.

WHAT IT MEANS: You can reduce the chance of getting breast cancer in the first place by 30 to 40% if you are physically active. But if you are diagnosed, no matter what your age, make sure exercise is part of your treatment strategy. Women who engaged in moderate-intensity activities, such as walking at a brisk pace for three hours a week (the method that showed promise in the study) two years after being diagnosed with breast cancer had a nearly 70 percent greater chance of survival.

The Center for Disease Control lists other moderate-intensity activities as:

• Recreational swimming
• Playing doubles tennis
• Biking 5 to 9 mph on level or slightly hilly terrain
• Scrubbing floors or washing windows
• Weight lifting using Nautilus machines or free weights

Here’s even more incentive to keep moving during such a difficult time: Walking in 30-minute spurts can counteract the blues and even temporarily lift people out of major depression, according to a 2006 University of Texas at Austin study.