The study is supported by a program project grant and thus includes many subprojects. Projects 1A through 1C were supported beginning in 1986. Project 1A examined the effects of cardiovascular and hormonal responses to standardized laboratory challenges as a function of race, sex, age, and normal blood pressure versus borderline hypertension. The subjects were classified according to four categories: Black or white race; male or female sex; normal or raised blood pressure; and ages 25-39 or 40-54, giving a total of 16 cells with 15 subjects in each. The subjects were given a physical examination, electrocardiogram, blood screening test as well as a battery of special tests including a Structured Interview for Type A behavior pattern, playing a video game, a test designed to elicit anger, and exercise on a bicycle ergometer. During these tasks subjects were monitored for heart rate and blood pressure, and blood was sampled for plasma catecholamines, renin, cortisol, aldosterone, and vasopressin. Various psychological tests were administered including the Cook-Medley hostility scale, the Life Orientation test, a job stress scale, the John Henryism Active Coping Scale and others. Urine samples were collected for electrolyte and catecholamine excretion and ambulatory blood pressure was monitored on a work day and on a non-work day.