The studies had several interrelated themes. One was to explore the relationships between environmental stress and blood pressure over a range of time courses, with acute laboratory studies at one extreme, and long- term prospective studies at the other. The basic model of stress included three elements: the objective nature of the stressor, the individual's perception of it, and his or her physiological susceptibility. This model incorporated elements of the Karasek Job Strain model and the Frankenhaueser effort-distress model, with two components corresponding to demand and control. A third dimension was social support. These models were tested under both laboratory and field conditions. Blood pressure was the main dependent variable, together with structural changes in the heart and carotid arteries. Five projects were included. Project l evaluated the ability of ambulatory blood pressure, and blood pressure variability, to predict cardiovascular morbidity, and also included a cross-sectional study comparing the relationships between blood pressure and target organ damage in Black and white individuals. The hypothesis that white coat hypertension is a condition associated with lower risk than sustained hypertension was also tested. Project 2 prospectively evaluated the effects of job strain and social support on blood pressure and other outcome variables in a working population. Project 3 studied psychosocial and hormonal factors influencing diurnal variations of blood pressure in women, including the changes associated with menstruation and the menopause. Project 4 assessed within-subject changes of blood pressure in subjects exposed to changing levels of occupational stress over two months. Project 5 examined the conceptual models of job strain, social support, and white coat hypertension in controlled laboratory conditions.