Summary Ischemic heart disease occurs at near-epidemic proportions in Western civilization. Although all persons, especially Caucasian males, are “at risk,” there is a constellation of factors that apparently characterizes those individuals whose lives may be jeopardized prematurely. Available epidemiologic evidence indicates that the presence of hypertension, hypercholesterolemia and heavy cigarette smoking, either singly or in combination, are definite risk factors in the over-all population. Factors such as excessive obesity, heavy coffee drinking, diabetes mellitus and a positive family history of ischemic heart disease are also important, even though additional clarification of their over-all importance is still needed. In more recent years, two other areas of the life pattern have been strongly implicated as risk factors; namely, behavioral characteristics and habits of physical activity, either occupational or leisure-time. Unfortunately, these two areas were not well explored in some of the earliest large-scale epidemiologic studies, and further documentation of their influence on the natural history of ischemic heart disease is still required. The evidence available at present strongly suggests that individuals can be classified prospectively according to their behavioral traits and habits of activity. In general, the individuals with overzealous, poorly directed drive, increased Hypochondriasis (MMPI) and increased Activity Drive (TTS) have a higher incidence of myocardial infarction than do those subjects who lack these characteristics. Rosenman and Friedman labeled such individuals as possessing personality pattern Type A, whereas Wolf et al. suggested that their life style was patterned after that of the Greek mythologic character Sisyphus. The rate of myocardial infarction appears to be approximately one-half that of the sedentary population in men who are either regularly physically active throughout life or who enjoy an occupation that demands regular physical activity; i.e., bus conductors, mailmen, etc. In general, lifelong physically active men are characterized by a paucity of risk factors, whereas the sedentary population and Type A individuals often possess one or more. These findings suggest that the clinical manifestations of ischemic heart disease should be preventable if a suitable program were instituted in early life, preferably in the adolescent years. Such a program should be multifaceted and should include appropriate dietary manipulation, psychotherapy or improved education regarding behavioral traits, and supervised programs of regular physical activity. Of the three approaches, physical activity might be considered the keystone, since it offers a positive approach to health maintenance and can serve as the source around which an individual modifies the remainder of his life style. Coordination of the educational system and family structure with the efforts of the physician will be required to make such a preventive program feasible and successful.0