The study was cross-sectional and longitudinal. An estimated 1,523 children, 7 to 14 years old at baseline, whose families reported essential hypertension, participated in a blood pressure screening following medical verification of their family history of hypertension. Children whose systolic blood pressures were in the 5th to 25th percentiles or 75th to 95th percentiles were recruited. A sample of children was obtained with relatively equal distributions by race, age, gender, and blood pressure grouping. Environmental stress factors evaluated include: psychophysiological responses to physical and psychological stressors including physical exercise testing, video game, and mental arithmetic tests; sociopsychological variables including anger and hostility coping styles; and sociostructural variables including socioeconomic status and family stability. The environmental risk factors were assessed within the context of other hypertension risk factors such as cholesterol level, sodium and alcohol intake, tobacco usage, resting blood pressure, and body weight. Each child and his parents were followed annually.