Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis

OBJECTIVE: We aimed to compare the efficacy of isometric exercise training (IET) versus high-intensity interval training (HIIT) in the management of resting blood pressure (BP). DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed (MEDLINE), the Cochrane library and SPORTDiscus were systematically searched. ELIGIBILITY CRITERIA: Randomised controlled trials published between 1 January 2000 and 1 September 2020. Research trials reporting the effects of IET or HIIT on resting BP following a short-term intervention (2-12 weeks). RESULTS: 38 studies were analysed (18 IET and 20 HIIT), including 1583 (672 IET and 911 HIIT) participants, of which 612 (268 IET and 344 HIIT) were controls.IET produced significantly greater reductions in resting BP compared with HIIT with systolic, diastolic and mean BP effect sizes of 8.50 mm Hg vs 2.86 mm Hg (Q=17.10, p<0.001), 4.07 mm Hg vs 2.48 mm Hg (Q=4.71, p=0.03) and 6.46 mm Hg vs 3.15 mm Hg (Q=4.21, p=0.04) respectively. However, HIIT reduced resting heart rate significantly more than IET (3.17bpm vs 1.34bpm, Q=7.63, p=0.006). CONCLUSION: While both modes are efficacious, IET appears to be the superior mode of exercise in the management of resting BP. However, HIIT may achieve wider physiological benefits, with greater reductions in resting heart rate.