Purpose: To compare the effectiveness of high-intensity aerobic interval training (AIT) with active recovery and continuous moderate-intensity exercise (CME) on exercise capacity and metabolic risk factors in adults with cardiometabolic disorders through a systematic review and meta-analysis.
Methods: Studies were selected from 5 electronic databases (PubMed, MEDLINE, CINAHL, Physiotherapy Evidence Database [PEDro] and Cochrane Library Register of Controlled Trials). Randomized controlled trials (RCTs), published in English, that compared the effects of AIT with CME on exercise capacity and metabolic risk factors in adults with cardiometabolic disorders were included. Aerobic interval training was defined as high-intensity training separated by active recovery periods; CME incurred identical energy expenditure as AIT. Each trial was evaluated using the PEDro scale. Weighted mean difference (WMD) and 95% CIs were used to determine the effect size for each outcome.
Results: Six RCTs with 153 participants (40 overweight/obesity, 19 with metabolic syndrome, and 94 with heart disease) were included. The mean value on the PEDro scale for these studies was 5.0. Aerobic interval training significantly increased peak oxygen consumption (WMD, 3.6 mL·kg·min; 95% CI, 2.3-4.9) with a trend of decreasing fasting glucose (WMD, -0.4 mmol/L; 95% CI, -0.9 to 0.2, P = .18) compared with CME. The effects on other metabolic risk factors were similar between AIT and CME.
Conclusion: Analysis of a limited number of studies with small sample sizes indicates that AIT is superior to CME in terms of improving exercise capacity. Further high quality studies with larger sample size are required to confirm this finding in adults with cardiometabolic disorders.