Epidemiologic studies in Olympic year 1984 suggest that personal athleticism alters trends in life-style and coronary heart disease. Analysis of 572 first attacks among 16,936 Harvard alumni, 1962 to 1972, and 1,413 total deaths, 1962 to 1978, shows that habitual postcollege exercise, not student sports play, predicts low coronary heart disease risk. Sedentary alumni, even ex-varsity athletes, have high risk. Sedentary students becoming physically active alumni acquire low risk. Exercise benefit is independent of contrary life-style elements—smoking, obesity, weight gain, hypertension, and adverse parental disease history—in affecting coronary heart disease incidence. Hypertension is clinically the strongest predictor of coronary attack, but inadequate exercise is strongest on a community basis. Exercise level is inversely related to total, cardiovascular, and respiratory mortality but less related to cancer or unnatural deaths. The current exercise revolution may improve life-style, cardiovascular health, and longevity. (JAMA 1984;252:491-495)