Pressor responsiveness, age and hypertension.

It has long been accepted that enhanced vascular reactivity is an integral part of the hypertensive state. This study investigates pressor responsiveness to the selective alpha 1-adrenoceptor agonist, phenylephrine, in 62 normotensive and hypertensive subjects aged 20-70 years. Since blood pressure increases with age, it is possible that effects attributed specifically to blood pressure will be confounded by age. The present study showed no correlation between responsiveness and starting blood pressure. However, responsiveness was positively correlated with age. These results suggest that it may be an oversimplification to attribute increased vascular responsiveness to the hypertensive state.