Clinically Meaningful Blood Pressure Reductions With Low Intensity Isometric Handgrip Exercise: A Randomized Trial

Abstract

There exists no examination of what is the minimum antihypertensive threshold intensity for isometric exercise training. Twenty two normotensive participants were randomly assigned to training intensities at either 5% or 10% of their maximal contraction. Twenty participants completed the study. Clinical meaningful, but not statistically significant, reductions in systolic blood pressure were observed in both 5% and 10% groups -4.04 mm Hg (95 % CI -8.67 to +0.59, p=0.08) and -5.62 mm Hg (95 % CI -11.5 to +0.29, p=0.06) respectively after 6 weeks training. No diastolic blood pressure reductions were observed in either 5 % -0.97 mm Hg (95 % CI -2.56 to +0.62, p=0.20) or 10 % MVC +1.8 mm Hg (95 % CI -1.29 to +4.89, p=0.22) groups respectively after training. In those unable to complete isometric exercise at the traditional 30 % intensity, our results suggest there is no difference between 5 and 10 % groups and based on the principle of regression to the mean, this could mean both interventions induce a similar placebo-effect.