Effect of Isometric Handgrip Training on Ambulatory Blood Pressure: a Multi-center Study

Meta-analysis studies have demonstrated that isometric training with handgrip promotes reductions in clinical blood pressure, reaching 8 mmHg for systolic blood pressure and 4 mmHg for diastolic. However, the effects of this training modality on ambulatory blood pressure, which is better discriminant of cardiovascular risk than clinical BP, remains uncertain. Thus, the ISOPRESS Network, consists of researchers from Brazilian institutions of education and research (Federal University of Santa Catarina, Federal University of Amazonas, Federal University of Sergipe, Federal Rural University of Pernambuco and Universidade Nove de Julho), will conduct a multi-center study to analyze the effects of isometric handgrip training on clinic and 24-h ambulatory blood pressure in patients with hypertension. For this, each research center will conduct a randomized controlled trial with medicated patients with hypertension, of both sex. The participants will be randomized into two groups: isometric handgrip training group (HBT: n = 25 per center) and control group (CG: n = 25 per center).Subjects assigned to the HBT will train three times per week, four sets of 2-min isometric contractions (using alternate hands) at 30% of maximal voluntary contraction, during 24 weeks. Subjects randomized to the CG will perform stretching and relaxation exercises three times per week, during 24 weeks. The evaluations will occur in three moments: baseline, post-12 and post-24 weeks. The primary outcome will be ambulatory blood pressure, while clinic blood pressure and cardiac autonomic modulation will be analyzed as secondary outcomes. For data analysis, in addition to descriptive statistics, two-way ANOVA for mixed model will be applied for within and between groups comparison. The level of significance that will be adopted is p<0.05.