Evaluation of the Safety and Efficacy of two different Isometric Exercises in the Reduction of Blood Pressure in People with Resistant Hypertension José Luís da Silva Lopes Porto,

Abstract

Over the years, there has been reluctance to include isometric exercises in hypertension treatment guidelines due to safety concerns and inconsistent efficacy data. However, recent research has demonstrated the benefits of isometric exercise, particularly the handgrip (IHG) and wall squat (IWS). Despite this, no studies have examined the effects of isometric exercise in people with resistant hypertension. This study aimed to analyse the blood pressure (BP) response to two isometric exercises - IHG and IWS - in order to evaluate their safety and effectiveness in individuals with resistant hypertension. Nine people aged between 40 and 75 years underwent a familiarization session (in which the procedures were explained and the intensity of IHG and IWS was assessed) followed by 3 randomized experimental sessions: a control session, an IHG session ( 4 x 2 min, at 30% of maximum voluntary contraction) and an IWS session (4 x 2 min, 95% of maximum heart rate achieved in the incremental test). BP was measured before, during each repetition (at 30s and 90s), immediately after and in the 12 hours following each session. Statistical analysis was done using SPSS v. 27. Significant differences in Systolic BP (SBP) and Diastolic BP (DBP) were found between IWS and IHG at multiple time points, with greater changes from baseline in IWS (e.g. last rep: 63/27 vs 36 /12 mmHg, p<0.05). One participant experienced excessive BP elevations on 3 occasions during IWS (i.e., SBP≥250 mmHg and DBP≥115 mmHg). No statistically significant differences were detected between the conditions, immediately after and in the 12 hours after the sessions, despite the reduction in mean SBP in the 12 hours after the sessions on the IHG and IWS days (Control - 120.2 mmHg; IHG - 114.0 mmHg; IWS - 116.9 mmHg; p= 0.641). Although most participants tolerated exercise, excessive BP elevations during IWS indicate a need for caution when prescribing isometric exercise until it is confirmed that it can be performed safely. Regarding effectiveness, none of the exercises showed statistical superiority in relation to Control, although reductions in mean SBP suggest potential clinical benefits.