Weightlifting outperforms voluntary wheel running for improving adiposity and insulin sensitivity in obese mice

Abstract

Background: Exercise is an effective intervention for obesity and type 2 diabetes, with significant physiological benefits over pharmacological interventions. However, there is limited preclinical data available comparing endurance and resistance exercise for the impacts on obesogenic pathology and glycemic control. Methods: Male mice were subjected to 8 weeks of diet-induced obesity (DIO) by high-fat diet (HFD) feeding concurrent with voluntary wheel running (endurance exercise (EEX)) or weightlifting (resistance exercise (REX)). Sedentary (SED) mice fed on normal chow (NC) or HFD were used as controls. Results: EEX and REX interventions significantly attenuated weight gain vs. HFD-SED due to reduction of fat mass, not changes in lean mass, as assessed by EchoMRI. While REX suppressed visceral and subcutaneous fat accumulation significantly, only EEX enlarged brown fat mass. Exercise tolerance testing (i.e., run-to-fatigue) revealed significantly improved exercise capacity in EEX group vs. NC-SED. Interestingly, although HFD led to trends of increased skeletal muscle mass, only EEX with HFD led to significant muscle weight gain. Neither exercise modality resulted in significant changes of hindlimb skeletal muscle contractile properties and cardiac function compared to SED mice on HFD. Importantly, REX showed significantly enhanced benefits over EEX in improving homeostatic model assessment of insulin resistance (HOMA-IR), glucose tolerance, and insulin tolerance. Conclusion: These results provide a direct and translatable comparison of endurance and resistance exercise training in a preclinical context of obesity and hyperglycemia. The current data set demonstrates an advantage of resistance exercise over endurance exercise in improving glucose and insulin tolerance under the condition of obesity, and that these improvements are independent of significant alterations of muscle weight gain and exercise performance.