Exploring the role of successful exercise-induced body weight loss on cardiometabolic health in individuals with metabolic syndrome.
BACKGROUND AND AIM: High-intensity interval training (HIIT) is known to improve cardiorespiratory fitness (i.e., VO2MAX), a key marker of cardiometabolic health in individuals with metabolic syndrome (MetS). Nonetheless, body weight loss is widely recognized as a crucial factor in reducing insulin resistance and improving metabolic risk factors. Thus, we aimed to determine the importance of body weight loss following exercise training on improving MetS. METHODS AND RESULTS: Two hundred and twenty-eight adults (55.3 ± 7.9 yr) with overweight/obesity (32.5 ± 4.6 kg·m-2) and MetS were randomized to: a) standard health care non-exercise group (CONTROL group, N=58) or b) standard health care plus 16 weeks of HIIT (EXER group, N=170). MetS (MetS z-score), insulin resistance (HOMA-IR), cardiorespiratory fitness (VO2PEAK), maximal cycling power (WPEAK), and body weight/composition were assessed. After intervention, EXER group participants were divided according to their weight loss response to training: i) those achieving the weight loss predicted from estimated exercise energy expenditure (-BW group, n=78; -3.3 ± 2.2 kg); ii) those not reaching the expected weight loss (=BW group, n=38; -0.7 ± 0.5 kg); iii) and those who gained weight (+BW group, n=54; 1.1 ± 1.0 kg). VO2PEAK significantly improved regardless of body weight loss response (-BW, 0.3 ± 0.3; =BW, 0.2 ± 0.3; +BW, 0.3 ± 0.2 L·min-1; all p < 0.001) compared to CONTROL group (0.0 ± 0.3 L·min-1). However, significant improvements in MetS z-score (-0.31 ± 0.41) and HOMA-IR (-0.7 ± 1.6) were observed only in the -BW group (both p < 0.001). CONCLUSIONS: Exercise recommendations should consider that greater improvements in MetS are observed when interventions are accompanied by successful body weight loss. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05120778.