Exercise Works, Even in Small Doses Results of a large, 5-year study of older men show that exercise need not be time-consuming to provide benefit to cardiovascular health. Researchers found that breaking up exercise into short bursts of activity throughout the day strengthened the heart just as well as one long workout. Collecting data on more than 7,300 men who reported their regular exercise habits, their heart disease risk was found to depend not on how long they exercised each day, but on how many overall calories they burned. Men who burned 4,400 calories per week through exercise were nearly 40% less likely to develop heart disease than were men who used up only 1,100 calories per week. This effect held, regardless of whether the men walked, climbed stairs, or played sports. Dr. Howard D. Sesso and his colleagues at the Harvard School of Public Health in Boston, Massachusetts, announced that it is "promising news" for sedentary people who want to take up exercise. In a separate study, the same researchers found that intense exercise such as running or swimming laps cut heart disease risk to a greater extent than moderate activity did. Among more than 12,500 middle-aged and older men, regular vigorous exercise reduced heart disease risk by up to 20%, while regularly walking was linked to only a 10% decline.