Physical activity during leisure time benefits our heart and longevity, but high workout levels on the job may actually hamper our health, report Danish researchers. Measuring the physical activity of 104,046 women and men of ages 20 to 100 for 11 years, researchers found that leisure physical activity reduced the risk of dying from heart disease by 26 to 41 percent, but high physical activity at work increased that risk by 13 to 27 percent. “A brisk, 30-minute walk will benefit your health by raising your heart rate and improving your cardiorespiratory fitness, while work activity often does not sufficiently increase heart rate to improve fitness,” says study author Andreas Holtermann, of the National Research Centre for the Working Environment, in Copenhagen.