The effect of high-intensity interval training versus moderate-intensity continuous on cardiorespiratory fitness in cardiac patients: a meta-analysis

Aims: The objective of this study was to determine the effect of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) in cardiac population on their cardiorespiratory fitness, through a meta-analysis of the recent available literature. It was hypothesised that HIIT would have a greater effect on improving cardiac patients exercise capacity than MICT. Method: A literature search was conducted between the 5th of July 2020 and the 19th of July 2020. To examine the effect of HIIT versus MICT on their V̇ O2peak/max in the cardiac population. The inclusion criteria were as follows; (A) studies HIIT protocol is identified as training between 85 – 100% of V̇ O2peak or V̇ O2max; (B) a HIIT session ≤ 4 minutes with passive or active recovery in between; (C) the study reported baseline V̇ O2max or V̇ O2peak; (D) the journal article was written in English. The exclusion criteria are as follows; HIIT protocol performed at intensity > 100% of V̇ O2max. Result: Eight studies, including 220 and 201 participants in the HIIT and MICT protocols, respectively. It was analysed within the meta-analysis. The results indicate that improvement of cardiorespiratory fitness is in favours of MICT over HIIT protocol (SMD = -0.32; 95% CI, -0.51 – 0.13) with moderate effect size. Conclusion: The high-intensity interval training protocol was not as effective in improving cardiorespiratory fitness in the cardiac population than MICT protocol