Age and the Hemodynamic Response to Posture and Exercise.
The effects of age on hemodynamic variables at rest, in response to orthostatic challenges, and during exercise were assessed from overall weighted statistical summaries of reports in the medical literature. In normotensive subjects at supine rest, cardiac output and stroke volume (p is less than 0.001), but not heart rate, declined with aging, whereas systemic vascular resistance increased (p is less than 0.001). The results were similar in hypertensives, but the slope of the change in cardiac output was steeper than in normotensives (p is less than 0.01). This age-related hemodynamic pattern was also observed in longitudinal follow-up studies. The orthostatic fall in stroke volume and rise in heart rate became less pronounced with increasing age (p is less than 0.05), but the postural increase in systemic vascular resistance was, on average, not related to age. Though the hemodynamic studies in healthy individuals observed that blood pressure is relatively well maintained when older subjects assume the upright position, population studies suggest that an increasing number of these subjects show a postural fall in blood pressure. This is overwhelming evidence that the oxygen uptake at peak exercise decreases with age, mainly related to a lesser peak cardiac output and heart rate (p is less than 0.001).
Fagard
Robert
R
Hypertension and Cardiovascular Rehabilitation Unit, Department of Pathophysiology, University of Leuven K.U.L., Leuven, Belgium.
Thijs
Lutgarde
L
Amery
Antoon
A