Persons at risk for hypertension may show elevated
blood pressure (BP) at rest and during mental stress; however,
the hemodynamics underlying the BP of those persons at
high risk are not well characterized. We chose 21 high
risk and 21 low risk men using their parental hypertension
history and resting systolic blood pressures on two screenings.
Then, on a day of extended rest versus a day with prolonged
mental arithmetic and reaction time tasks, we examined
whether high risk BP elevations reflected greater vascular
resistance or cardiac output. High risk men had raised
systolic/diastolic pressures (Fs = 74/15, ps
< .0001/.0001) and higher vascular resistance (F
= 6.6, p < .02) with minimal differences in
heart rate and cardiac output. This finding implicates
vascular resistance as the altered element in BP control
in these high risk men tested in a familiar environment
with minimal task-related threat.