Older men (60-69 years) exhibited significantly lesser increases in heart rate and diastolic pressure in response to graded postural stress compared to younger men.
Observational
Does age affect the hemodynamic response to graded postural stress in healthy men?
Older men exhibit blunted heart rate and diastolic pressure responses to postural stress, providing a physiological mechanism for the increased incidence of postural hypotension in the elderly.
We studied the hemodynamic effect of graded gravity (g) increments from 10 degrees headdown (-0.17 g) to 70 degrees headup (+0.94 g) tilt on young (20 to 29 years), middle-aged (40 to 49 years) and older (60 to 69 years), healthy men. Thoracic blood volume and ventricular stroke volume decreased linearly with increasing g levels. Heart rates and diastolic pressures increased, but only at the higher g levels; however, the increases were significantly less in the 60- to 69-year-old men. The results indicate that thoracic blood volume and ventricular stroke volume are remarkably gravity dependent over the entire tilt range in all groups, the lesser heart rate and diastolic pressure responses in older participants are significant circulatory handicaps and may contribute to the increased incidence of postural hypotension in elderly persons, the sharp rise in vascular resistance at lower +g levels (when arterial pressure is unchanged) suggests that cardiopulmonary reflexes play an important role in human circulatory adjustment to the headup posture.
Smith et al. (Wed,) conducted a observational in Healthy. Older age (60-69 years) vs. Younger age (20-29 and 40-49 years) was evaluated on Hemodynamic response (heart rate and diastolic pressure). Older men (60-69 years) exhibited significantly lesser increases in heart rate and diastolic pressure in response to graded postural stress compared to younger men.