Abstract
OBJECTIVE: Isometric exercise can be an alternative approach to lowering blood pressure in individuals with hypertension. However, it is uncertain whether the muscle mass involved can influence Post-Exercise Hypotension (PEH). Thus, the authors evaluate the acute effect of an isometric exercise session with a Small Muscle Mass (SMM) and a Large Muscle Mass (LMM) on Systolic (SBP) and Diastolic (DBP) blood pressure in individuals with hypertension. METHOD: Randomized clinical trial with 36 volunteers aged 40‒70y with hypertension allocated into (n = 12/group): control group (no exercise), SMM group (bilateral isometric handgrip contractions using a hydraulic handheld dynamometer), and LMM group (bilateral isometric full knee extension on a leg extension machine). Both exercise interventions consisted of 4 × 2 min of bilateral contraction at 30 % of the individual's maximum capacity. The authors used 24-hour Ambulatory Blood Pressure Monitoring (ABPM) after the interventions. One-way ANOVA or Generalized Estimation Equations (GEE) were used to test for potential differences (p < 0.05). RESULTS: The authors found no increase in SBP/DBP immediately after the interventions. However, 24 h ABPM revealed lower SBP post-intervention in the SMM group (Δ-4.1 mmHg; p = 0.044) and the LMM group (Δ-5.6 mmHg; p = 0.040) compared to the control group, with no difference between these groups. DBP did not change over a period of 24 h ABPM. CONCLUSIONS: In conclusion, isometric exercise-induced PEH assessed by 24 h ABPM regardless of the muscle mass involved. This study shows that both interventions may contribute to lowering blood pressure in individuals with hypertension. TRIAL REGISTRATION: www. CLINICALTRIALS: gov; ID NCT03982758.