The influence of age and blood pressure on the hemodynamic and humoral response to head-up tilt.

It has been reported that postural hypotension in the elderly is common. However, these studies included institutionalized and more or less disabled persons. Furthermore, postural hypotension may be related to baseline blood pressure. In this study, the influence of age and blood pressure on the hemodynamic and plasma catecholamine responses to orthostatic stress was investigated in young and old normotensive and hypertensive healthy subjects. In normotensive and hypertensive elderly persons, the percentage blood pressure responses during tilt were not significantly different from that seen in young normotensives. We measured a slight decrease of systolic blood pressure and a slight increase of diastolic blood pressure. The hypertensive young patients showed an enhanced diastolic blood pressure response with no fall in systolic blood pressure, in contrast to the normotensive young subjects. Both elderly groups had a lower increase of heart rate than the young subjects. The percentage increase in norepinephrine after tilting was significantly lower in elderly hypertensives than in elderly normotensives and young hypertensives. The presence of hypertension was associated with a decrease in blood pressure, but age had no influence on the change in blood pressure during tilt. In this group of healthy elderly subjects, there was no significant orthostatic hypotension when the blood pressure course of the entire tilt test was taken into account.