Effect of aerobic exercise training followed by a low-calorie diet on metabolic syndrome risk factors in men

Background and aims: Whether low-volume, high-intensity, interval training (HIIT) is an adequate exercise method for improving metabolic risk factors is controversial. Moreover, it is not known if performing a short-term, low-calorie diet intervention (LCDi) after a HIIT program affects risk factors. This study investigated how an 8-week, 3 times/week exercise intervention (EXi) incorporating either HIIT or moderate-intensity continuous training (MICT) followed by a 4-week LCDi affects risk factors. Methods and results: Twenty-six male workers with metabolic risk factors (47.4 +/- 7.1 years; cardiorespiratory capacity ((V) over dotO(2peak)) of 28.5 +/- 3.9 ml/kg/min) were randomly assigned to either the HIIT (3 sets of 3-min cycling with a 2-min active rest between sets, 180 kcal) or MICT (45 min, 360 kcal) group. After the EXi, all subjects participated in a 4-week LCDi (4 counseling sessions). During the EXi, (V) over dotO(2peak) improved more (P < 0.05) through HIIT (25.4 +/- 14.6%) than through MICT (14.9 +/- 12.8%), whereas improvements in body fat and HDL cholesterol were similar. During the LCDi, some risk factors improved further (P < 0.05) without any group differences, while (V) over dotO(2peak) in the HIIT group decreased (P < 0.05) to the same level as in the MICT group. Conclusion: (V) over dotO(2peak) increased more with HIIT than with MICT during the EXi despite HIIT having a lower exercise volume than MICT, but this advantage of HIIT promptly disappeared through detraining. An intervention strategy consisting of 8 weeks of either HIIT or MICT followed by a 4-week LCDi has a positive effect on metabolic risk factors. Clinical Trial Registration: UMIN11352. (C) 2015 Elsevier B.V. All rights reserved.