Sex Differences in Cardiometabolic Health Indicators following HIIT in Patients with Coronary Artery Disease.

Way, Kimberley L; Vidal-Almela, Sol; Moholdt, Trine; Currie, Katharine D; Aksetøy, Inger-Lise Aamot; Boidin, Maxime; Cornelissen, Veronique A; Joa, Kyung-Lim; Keech, Andrew; Jayo-Montoya, Jon Ander; Taylor, Jenna L; Fouriner, Karine; Reed, Jennifer L

PURPOSE Cardiorespiratory fitness (CRF) is an independent predictor of mortality, and females typically achieve smaller improvements in CRF than males following exercise-based cardiac rehabilitation (CR). High-intensity interval training (HIIT) has been shown to produce superior improvements in CRF than traditional CR, but the sex-differences are unknown. The purpose of this systematic review and meta-analysis was to evaluate sex-differences for changes in CRF and cardiometabolic health indicators following HIIT in adults with coronary artery disease (CAD).Methods and ResultsA systemic search of 5 electronic databases for studies examining the effect of HIIT on measured CRF and cardiometabolic health indicators in adults with CAD was performed. Data (published and unpublished) from 14 studies were included in the meta-analyses with ~8-fold greater male than female participation (n=836 vs. n=103). Males with CAD achieved a near significant absolute improvement in CRF (mean difference [MD]: 1.07, 95% CI: -0.08 to 2.23 mL/kg/min, p=0.07) following HIIT when compared to control; there were insufficient data to conduct such an analysis in females. Significantly smaller improvements in CRF were experienced by females than males (MD: -1.10, 95% CI: -2.08 to -0.12 mL/kg/min; p=0.03); there was no sex-difference for the relative (percentage) change in CRF following HIIT. Females achieved significantly smaller reductions in body mass index (MD: -0.25, 95% CI: -0.03 to -0.47 kg/m2; p=0.02) and fasting blood glucose (MD: -0.38, 95% CI: -0.05 to -0.72; p=0.03); no sex-differences were observed for other cardiometabolic health indicators. CONCLUSION There are no sex-differences for relative improvements in CRF following HIIT; however, females are greatly underrepresented in trials. Future studies should increase female participation and perform sex-based analyses to determine sex-specific outcomes with HIIT.