The Effects of High-Intensity Interval Training on Exercise Capacity and Prognosis in Heart Failure and Coronary Artery Disease: A Systematic Review and Meta-Analysis

Abstract

Objective: The purpose of this study is to compare the effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on exercise capacity and several prognostic markers in patients with coronary artery disease (CAD) and heart failure (HF).

Methods: This systematic review is registered on the INPLASY website (number: INPLASY202080112). We conducted a comprehensive search in eight databases of literature before September 13, 2019. Trials comparing HIIT and MICT in participants with CAD or HF aged 52-78 years were included. Exercise capacity (peak oxygen consumption (peak VO₂)) and prognostic markers, such as the anaerobic threshold (AT), minute ventilation/carbon dioxide production (VE/VCO₂) slope, left ventricular ejection fraction (LVEF), and prognostic value of the predicted VO₂ max per cent (the predicted VO₂ peak (%)) were examined.

Results: A total of 15 studies were included comprising 664 patients, 50% of which were male, with an average age of 60.3 ± 13.2 years. For patients with CAD, HIIT significantly improved peak VO₂ values (95% CI 0.7 to 2.11) compared with MICT, but peak VO₂ values in patients with HF did not seem to change. For training lasting less than eight weeks, HIIT significantly improved peak VO₂ values (95% CI 0.70 to 2.10), while HIIT lasting 12 weeks or longer resulted in a modestly increased peak VO₂ value (95% CI 0.31 to 5.31). High-intensity interval training significantly increased the AT when compared with MICT (95% CI 0.50 to 1.48). High-intensity interval training also caused a moderate increase in LVEF (95% CI 0.55 to 5.71) but did not have a significant effect on the VE/VCO₂ slope (95% CI -2.32 to 0.98) or the predicted VO₂ peak (95% CI -2.54 to 9.59) compared with MICT.

Conclusions: High-intensity interval training is an effective therapy for improving peak VO₂ values in patients with CAD. High-intensity interval training in the early stage (eight weeks or fewer) is superior to MICT. Finally, HIIT significantly improved prognostic markers, including the AT and LVEF in patients with CAD and HF.

Figure 1

Systematic review process. CAD: coronary artery disease; HF: heart failure.

Figure 2

Risk of bias assessment.

Figure 3

Forest plots of the effect of HIIT and MICT on peak VO₂ for patients with CAD and HF. HIIT: high-intensity interval training; MICT: moderate-intensity continuous training; peak VO₂: peak oxygen consumption; CAD: coronary artery disease; HF: heart failure; SD: standard deviation; CI: confidence interval.

Figure 4

(a) Subgroup analysis of HIIT and MICT on peak VO₂ according to disease categories (CAD versus HF); (b) sensitivity analysis. HIIT: high-intensity interval training; MICT: moderate-intensity continuous training; peak VO₂: peak oxygen consumption; CAD: coronary artery disease; HF: heart failure; SD: standard deviation; CI: confidence interval.

Figure 5

Subgroup analysis of HIIT and MICT on peak VO₂ according to training duration (≤8weeks, 8-12weeks, and ≥12weeks). HIIT: high-intensity interval training; MICT: moderate-intensity continuous training; peak VO₂: peak oxygen consumption; CAD: coronary artery disease; HF: heart failure; SD: standard deviation; CI: confidence interval.

Figure 6

Forest plot summary of the effect of HIIT and MICT on prognostic markers in patients with CAD and HF: (a) anaerobic threshold (AT); (b) left ventricular ejection fraction (LVEF); (c) the VE/carbon dioxide production (VCO₂) slope (the VE/VCO₂slope); (d) the prognostic value of percent predicted VO₂max (the predicted VO₂ peak (%)). HIIT: high-intensity interval training; MICT: moderate-intensity continuous training; CAD: coronary artery disease; HF: heart failure; SD: standard deviation; CI: confidence interval.