A new study by University of South Carolina researchers indicates aerobically fit women are three times less likely to die of breast cancer than those who seldom exercise.

The latest addition to the growing evidence on the benefits of aerobic exercise is reported in the April issue of the scientific journal Medicine & Science in Sports & Exercise.

Researchers from USC's Arnold School of Public Health studied 14,000 women who were given preventive medical exams and treadmill tests at the Cooper Clinic in Houston from 1970-2001. At the time of their exams, the women, ages 20 through 83, had no history of breast cancer.

Based on the treadmill tests, the women's fitness was classified as low, moderate or high. Researchers compared the fitness levels of the 68 women in the study group who had died of breast cancer through 2003.

"Women in the study's lowest fitness category were nearly three times more likely to die from breast cancer than women in the most fit group," said Dr. Steve Blair, a USC researcher and a past president of the American College of Sports Medicine.

To reach the moderate fitness category, women need to exercise about 150 minutes per week. High fitness translates to 300 minutes per week.

"With more than 40,000 women dying each year from this disease, finding a strong association between fitness, which can be improved by the relatively inexpensive lifestyle intervention of regular physical activity, such as walking, is exciting," Blair said.

Exercise should be a standard part of preventive treatment for a number of health problems, according to the American College of Sports Medicine.

The new study also backed up previous findings that exercise helps control cholesterol levels, lowers blood pressure and lessens the likelihood for diabetes and heart disease.