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Acute hypotensive effect of dynamic, isometric and combined (dynamic + isometric)resistance exercise in medicated hypertensives men: hemodynamic and autonomic mechanisms

Grant number: 18/23653-3
Support type:Regular Research Grants
Duration: August 01, 2019 - July 31, 2021
Field of knowledge:Health Sciences - Physical Education
Principal Investigator:Cláudia Lúcia de Moraes Forjaz
Grantee:Cláudia Lúcia de Moraes Forjaz
Home Institution: Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Assoc. researchers: David Andrew Low

Abstract

Dynamic and handgrip isometric resistance training have been shown to decrease blood pressure (BP) by different mechanisms, suggesting that their combination may produce a greater hypotensive effect in hypertensives (HT). Additionally, each resistance exercise session may produce post-exercise hypotension (PEH), which has clinical relevance when presents significant magnitude and persists for many hours. In addition, PEH can be used to predict the chronic BP responses to training, which justifies studying PEH before investigating the chronic effects of training that implies in more time and investment. A single session of dynamic (DE) and isometric handgrip (I-hE) resistance exercises might cause PEH, but its duration and mechanisms need to be studied. In addition, no previous study has investigated the effects of the combination between these exercises (CE), which may potentiate the hypotensive effect. Thus, this study will evaluate and compare the effects of a single session of DE, I-hE and CE on post-exercise BP and its mechanisms. Sixty medicated hypertensive men will be randomized to one of the following sessions: control (70 min seated rest); DE (8 exercises, 3 sets, repetitions to moderate fatigue, 50% of 1RM); I_hE (4 sets, unilateral handgrip, alternating members, 2 min, 30% of MVC); and CE (DE + I-hE). In each session, before and after the interventions, the following variables will be measured: clinic and ambulatory BP; systemic hemodynamics (cardiac output, systemic vascular resistance, heart rate and stroke volume); vascular function (forearm blood flow, endothelial function, shear stress and arterial stiffness); and cardiovascular autonomic modulation (sympathetic and parasympathetic cardiac modulations, baroreflex sensitivity and sympathetic vasomotor modulation). Data will be compared between sessions and times of measurement by mixed analyses of variance (ANOVAs), considering p<0.05 as significant. (AU)