Functional high-intensity interval training is not equivalent when compared to combined training for blood pressure improvements in postmenopausal women: a randomized controlled trial

Introduction Low-volume functional high-intensity interval training (F-HIIT) improves cardiorespiratory fitness, body composition, and physical function similarly to combined training (CT, gold standard protocol), however no previous studies have compared the F-HIIT equivalence with CT in reducing blood pressure in older people, particularly in postmenopausal women (PW). Therefore, the aim of this study (trial registration: NCT03200639) was designed to test whether F-HIIT of low volume is an equivalent strategy to CT for improving blood pressure (BP) in PW. Material and Method Forty-nine PW were divided into two groups: F-HIIT and CT. The F-HIIT protocol was composed of 10 sets of 60 seconds of high-intensity exercises interspersed with 60 seconds of low-intensity exercises for recovery. The CT protocol was composed of 30 minutes of moderate-intensity walking, followed by five total body resistance exercises. Both protocols were performed 3-times-a-week for 12 weeks. The BP from rest condition (before exercise) was measured before and after 12 weeks of intervention in both groups, using an automatic blood pressure monitor. The boundaries values for equivalence for systolic and diastolic BP was set at 5.14 and 2.92 mmHg, respectively. Results There was only a significant reduction (P < .05) in systolic BP in CT group from baseline (-3.2 (95% CI, -6.2 to -0.2) mmHg). The difference of systolic BP between F-HIIT and CT was 5.8 (95% CI, 1.3-10.4) mmHg, showing non-equivalence (inferiority) for F-HIIT. Conclusion Thus, these results suggest that low-volume F-HIIT protocol is not an equivalent strategy when compared to CT for BP improvements in PW.