Exercise Improves Breast Cancer Survival

Medical Author: Melissa Stoppler, M.D.
Medical Editor: William C. Shiel, Jr, MD, FACP, FACR

Walking just one or more hours per week or undertaking a comparable amount of physical activity may improve survival in women who have breast cancer, according to a study of over 2,900 women with breast cancer.

Doctors at Harvard Medical School studied female registered nurses who were enrolled in the Nurses' Health Study and who were diagnosed with breast cancer in stages I-III between 1984 and 1998. The researchers looked at the women's responses to questions concerning their overall levels of physical activity, measured as metabolic equivalent task (MET) hours. Three MET-hours is equivalent to walking at average pace of 2 to 2.9 mph for 1 hour. The surviving women were followed in the study until June 2002.

When compared with women who took part in less than three MET-hours of activity per week, those who engaged in 3 to 8.9 MET-hours per week had a 20% lower death rate. For 9 to 14.9 MET-hours of physical activity, the risk of death was 50% lower. Higher levels of activity (15-23.9 and 24+ MET-hours) resulted in decreases in death rate of 44% and 40%, respectively, when compared with inactive women.