Cardiovascular reactivity (CVR) is the change in a cardiovascular parameter in response to a discrete environmental stimulus. A leading theory linking behavior to cardiovascular diseases such as atherosclerosis and hypertension proposed that an exaggerated physiological response to a psychological challenge increased the risk for development of disease. Such a link had not been established conclusively in 1988. To a considerable extent, this might have been due to the fact that numerous approaches were devised to elicit and measure CVR. Furthermore, no single test or combination of tests was available which would be suitable for administering to large numbers of individuals who differed in age, gender, cultural or ethnic background, and socioeconomic status, as would be required for definitive prospective studies of reactivity and cardiovascular disease.