Baroreflex sensitivity is higher during acute psychological stress in healthy subjects under beta-adrenergic blockade.
Author(s): Truijen J, Davis SC, Stok WJ, Kim YS, van Westerloo DJ, Levi M, van der Poll T, Westerhof BE, Karemaker JM, van Lieshout JJ
Affiliation(s): Department of Internal Medicine, Academic Medical Center, University of Amsterdam, The Netherlands.
Publication date & source: 2011-02, Clin Sci (Lond)., 120(4):161-7.
Publication type: Randomized Controlled Trial; Research Support, Non-U.S. Gov't
Acute psychological stress challenges the cardiovascular system with an increase in BP (blood pressure), HR (heart rate) and reduced BRS (baroreflex sensitivity). beta-adrenergic blockade enhances BRS during rest, but its effect on BRS during acute psychological stress is unknown. This study tested the hypothesis that BRS is higher during acute psychological stress in healthy subjects under beta-adrenergic blockade. Twenty healthy novice male bungee jumpers were randomized and studied with (PROP, n=10) or without (CTRL, n=10) propranolol. BP and HR responses and BRS [cross-correlation time-domain (BRSTD) and cross-spectral frequency-domain (BRSFD) analysis] were evaluated from 30 min prior up to 2 h after the jump. HR, cardiac output and pulse pressure were lower in the PROP group throughout the study. Prior to the bungee jump, BRS was higher in the PROP group compared with the CTRL group [BRSTD: 28 (24-42) compared with 17 (16-28) ms.mmHg-1, P<0.05; BRSFD: 27 (20-34) compared with 14 (9-19) ms.mmHg-1, P<0.05; values are medians (interquartile range)]. BP declined after the jump in both groups, and post-jump BRS did not differ between the groups. In conclusion, during acute psychological stress, BRS is higher in healthy subjects treated with non-selective beta-adrenergic blockade with significantly lower HR but comparable BP.