Harvard Women's Health Watch

Snapshots from the Women’s Health Initiative Observational Study

Almost 94,000 women are enrolled in the Women's Health Initiative Observational Study. For an average of nearly eight years, they have answered annual questionnaires about their health and activities. Based on the data, researchers have found the following: Physical activity is associated with a 30%–40% reduction in risk for heart disease. Strenuous exercise and brisk walking (about one mile per 15 minutes) confer the same degree of benefit. Breast cancer rates are 18% lower in women who walk briskly for 1.25–2.5 hours per week and even lower for women who briskly walk 10 hours or more per week.
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