Effect of isometric handgrip training on resting blood pressure in adults: a meta-analysis of randomized controlled trials

INTRODUCTION: The aims of this study were to update the meta-analysis of the effect of isometric handgrip (IHG) training on resting systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) in healthy adults, and to analyze the association between IHG training and participants with different initial BP status. EVIDENCE ACQUISITION: PubMed, EMBASE, and Cochrane library were searched for eligible studies until Nov. 24, 2014. Cochran's Q statistic and the I2 statistic were used to assess the heterogeneity among included studies, and for the homogeneous outcomes (P≥0.05 and I2<50%) a fixed-effects model was selected for meta-analysis, while a random-effects model was applied for heterogeneous outcomes (P<0.05 or I2≥50%). Mean difference (MD) with 95% confidence interval (CI) was calculated to evaluate the effects of IHR on participants. EVIDENCE SYNTHESIS: A total of 7 trials from 6 articles were included, consisting of 157 subjects. The results suggested that SBP (MD=-8.33, 95% CI: -11.19 to -5.46; P<0.01) and DBP (MD=-3.93, 95% CI: -6.14 to -1.72; P<0.01) were significantly decreased in IHG training group compared with control group. In subgroup analysis, SBP, DBP, and HR were all significantly decreased in prehypertensive subjects (P<0.01). In medicated hypertensive subgroup and normotensive subgroup, only SBP and DBP were significantly reduced (P<0.01). CONCLUSIONS: IHG training lowers resting SBP and DBP in healthy adults, and IHG training may be an efficacious form of clinical treatment or prevention of hypertension.