CLINICS 2011;66(9):1523-1529 CLINICAL SCIENCE DOI:10.1590/S1807-59322011000900003 Impaired hemodynamic response to mental stress in subjects with prehypertension is improved after a single bout of maximal dynamic exercise Renata Frauches Medeiros, Bruno Moreira Silva, Fabricia Junqueira Neves, Natalia Galito Rocha, Allan Robson Kluser Sales, Antonio Claudio Nobrega Department of Physiology and Pharmacology & Postgraduate Program in Cardiovascular Sciences, Fluminense Federal University, Niteroi/RJ, Brazil. INTRODUCTION: High blood pressure during mental stress in subjects with prehypertension is associated with blunted vasodilation in skeletal muscles, which might be improved by an acute bout of exercise. OBJECTIVE: To investigate the hemodynamic responses to mental stress before and after a bout of exercise in subjects with prehypertension. METHOD: Eighteen subjects with prehypertension and 16 with normotension underwent a mental stress test before and after a maximal cardiopulmonary exercise test on a treadmill. Blood pressure was measured by auscultation, and forearm blood flow was measured by venous occlusion plethysmography; from these measurements, the vascular conductance was calculated. RESULTS: Subjects with prehypertension had a higher mean blood pressure during mental stress (prehypertension 112¡2 vs. normotension 101¡3 mm Hg, p,0.05), and their vascular conductance did not increase (baseline 0.025¡0.004 vs. mental stress 0.022¡0.003 a.u., p.0.05). After the exercise bout, the mean blood pressure during mental stress was lower in subjects with prehypertension (before exercise 112¡2 vs. after exercise 107¡2 mm Hg, p,0.05), and vascular conductance increased (baseline 0.011¡0.001 vs. mental stress 0.024¡0.004 a.u., p,0.05). CONCLUSION: Subjects with prehypertension had elevated blood pressure and a blunted vasodilator response during mental stress, but their blood pressure was attenuated and their vasodilator response was normalized after a single bout of maximal dynamic exercise. KEYWORDS: Psychological stress; Blood pressure; Blood flow; Physical exercise; Hypertension. Frauches RM, Silva BM, Neves FJ, Rocha NG, Sales ARK, Nobrega AC. Impaired hemodynamic response to mental stress in subjects with prehypertension is improved after a single bout of maximal dynamic exercise. Clinics. 2011;66(9):1523-1529. Received for publication on February 8, 2011; First review completed on March 16, 2011; Accepted for publication on May 16, 2011 E-mail: anobrega@id.uff.br Tel.: 55 21 2629-2404 INTRODUCTION Arterial hypertension (HT) affects approximately one billion people worldwide, and as the population ages, this number tends to increase.1 The classification of prehyper- tension (PHT) was introduced in the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. This classification focuses attention on a segment of the popula- tion at elevated risk of developing cardiovascular disease and for whom therapies that prevent or delay the onset of HT would be valuable.1 Copyright 2011 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Mental or psychological stress occurs on a daily basis, and the ability of organisms to respond to it is natural and necessary. The cardiovascular system participates exten- sively in the response to stressful situations, and some of its adjustments involve increases in systemic blood pressure2,3 and vasodilation in skeletal muscles.4,5 How- ever, it has been shown that subjects with PHT have an augmented blood pressure response to mental stress,6-8 which has been associated with an increased risk for the development of HT.2,3 Santangelo et al.6 suggested that one mechanism that might lead to this enhanced pressor response is blunted muscle vasodilation during mental stress. More recently, Schwartz et al.7 found that blunted vasodilation in skeletal muscles in subjects with PHT was not associated with muscle sympathetic nerve activity. Therefore, it is important to assess the impact of factors that might attenuate or reverse the enhanced pressor response and blunted muscle vasodilation during mental stress in subjects with PHT. 1523