Effects of using high-intensity interval training and calorie restriction in different orders on metabolic syndrome: A randomized controlled trial.

Abstract

Studies of the effectiveness of high-intensity interval training (HIIT) combined with calorie restriction (CR) are very limited, and the most effective order of intervention is unclear. Therefore, we investigated the impact of time-efficient HIIT with CR intervention on metabolic syndrome (MetS) and the impact of the intervention order on changes in MetS risk factors. Thirty-two participants with MetS underwent an 11-wk intervention program comprising 8 wk of HIIT and 3 wk of CR. Participants were randomly assigned to either the HIIT-then-CR or CR-then-HIIT groups. Thereafter, the CR-then-HIIT group performed a further 8 wk of training once per week after the initial intervention period. Risk factors for MetS and peak oxygen uptake (VO2peak) were assessed during the entire study period. During the 11-wk intervention period, body composition, MetS risk factors, and VO2peak significantly improved in both groups. No significant differences in these improvements were attributable to the intervention order; nonetheless, there was a tendency toward larger effect sizes in the CR-then-HIIT group. During the postintervention period (8 wk), a single weekly HIIT session prevented VO2peak reduction in the CR-then-HIIT group (-2.0 ± 7.2%; P=0.31). The time-efficient intervention program with HIIT and CR had a beneficial effect on MetS; however, the intervention order had no influence on the changes in risk factors.