Psychophysiologic reactions to behavioral challenges were examined in men aged 55 or less with no prior history of cardiovascular disorder. Three age-matched groups of twelve were recruited through factory screening: mild hypertensives (blood pressure in the range 175/105-145/90 persisting on retest), transient hypertensives (blood pressure above criterion on screening, falling on retest), and normotensives. Clinical examination, a laboratory rest session and period of blood pressure self-monitoring were followed by a laboratory stress session. The latter involved performance of two tasks demanding active behavioral coping (the Stroop interference task and video game) and one passive condition (a distressing movie). Mild hypertensives showed significantly greater pressor reactions (both in absolute and percentage terms) than normotensives to tasks requiring active behavioral coping, but not to the passive condition. The transient hypertension group produced heightened reactions in diastolic but not systolic pressure. Greater heart rate and pulse transit time reactions were also observed in the transient group, suggesting that exaggerated cardiac responsiveness to active challenges may be characteristic of the prehypertensive profile. No differences were recorded in electrodermal or respiratory variables, or in self-reported tension. Exaggerated pressor responses were also associated with high scores on the Hostility and Direction of Hostility questionnaire, and an absence of coronary-prone behavior. Implications for the etiology of essential hypertension are considered.

1. Ambulatory blood pressure monitoring was carried out in 10 subjects for a period of 48 h, the first or second 24 h part of which was selected randomly to be a period of complete bed rest. 2. Heart rate was significantly lower throughout the period of bed rest except for the period 04.00-08.00 hours, when there was little difference. 3. The circadian variation of blood pressure was reduced during the day of bed rest but this was mainly due to higher night-time pressures.