Cardiovascular response of young and older males to mental challenge.

Blood pressure, heart rate, rate pressure product, heart rate variability, stroke volume, cardiac output, peripheral resistance, and cardiac contractility derived from impedance cardiography were obtained from 15 young and 15 old males during and after the Stroop task. The old group demonstrated significantly higher absolute heart rate, systolic and mean arterial pressure, peripheral resistance, and rate pressure product, and lower cardiac output, stroke volume, and heart rate variability both during and recovering from Stroop. The young group showed significantly greater relative heart rate increase at the start of Stroop, higher relative levels of contractility during and recovering, and greater relative levels of peripheral resistance during and recovering from Stroop. Overall, old compared to young subjects possessed greater absolute but smaller relative cardiovascular responses during and recovering from Stroop. These results suggest that although the aging cardiovasculature may be less reactive, it may be under greater hemodynamic stress both during rest and mental challenge.