High-intensity interval versus moderate-intensity continuous training: Superior metabolic benefits in diet-induced obesity mice

Aims: Exercise is beneficial in obesity, however, the debate about the value of high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) has been long lasting. Therefore, here we have compared the possible beneficial effects of two different exercise training regimes in a mouse model of diet-induced obesity (DIO). Materials and methods: Following 7 wk. on high fat diet (HFD), ten-week-old male ICR mice (n = 30) were assigned to HIIT, distance-matched MICT or remained sedentary for the next 8 constitutive weeks while maintaining the dietary treatments. Age-matched sedentary mice with standard diet were used as a control (n = 10). Exercise was performed on a motorized treadmill for 5 days a week. Key findings: Both modes of exercise ameliorated adiposity and related metabolic dysfunction induced by HFD and sedentary lifestyle, while mice following HIIT exhibited significantly lower body weight, percentage of fat mass and smaller adipocyte size. HIIT was more favorable in preventing liver lipid accumulation by restoring mRNA levels of genes involved in hepatic lipogenesis (SREBP1, ACC1, FAS) and beta-oxidation (PPAR alpha, CPT1 alpha, HAD). In addition, HIIT was more efficient in mitigating adipose tissue inflammation and insulin insensitivity, partly dependent on abrogating phosphorylation of JNK/IRS1 (Ser307) pathway. Moreover, only HIIT led to pronounced beige adipocyte recruitment in inguinal subcutaneous adipose tissue. Significance: We conclude that HIIT contribute a more favorable regulation of metabolic dysfunctions in DIO mice compared with MICT.