Exercise and Ectopic Fat in Type 2 Diabetes

Background: Ectopic fat is an independent cardiometabolic risk factor for type 2 diabetes (T2D). Physical activity leads to increased cardiorespiratory fitness (CRF) and is a cornerstone therapy for T2D. While current recommended physical activity levels are effective for improving cardiometabolic health, few people achieve these, therefore, it is important to explore alternate yet efficacious exercise interventions that reduce cardiometabolic risk factors such as ectopic fat in T2D. Studies: Study 1 of this thesis assessed the association between CRF and non-alcoholic liver disease (NAFLD) in inactive overweight and obese adults via cross-sectional analysis; study 2 of this thesis assessed the effect of regular exercise on ectopic fat in T2D via systematic review and meta-analysis; study 3 of this thesis assessed the efficacy of a novel low-volume high-intensity interval training (HIIT) intervention and a traditional moderate-intensity continuous training (MICT) intervention vs. placebo (PLA) for improving liver fat (LF), pancreas fat (PF) and other cardiometabolic risk factors in obese inactive adults with T2D. Results: The results of study 1 demonstrated that CRF was significantly associated with NAFLD in inactive overweight and obese adults. The association was largely explained by anthropometric and circulating liver enzyme levels; the results of study 2 showed that aerobic exercise (AEx) led to significant reductions in visceral adipose tissue vs. control and a similar relationship was observed for LF, however, there was a lack of data to confirm this; the results of study 3 demonstrated that the HIIT and MICT interventions led to significant improvements in LF, PF and glycaemic control vs. PLA. Conclusions: The findings from this thesis showed that AEx is an effective therapy for reducing ectopic fat and improving cardiometabolic health in T2D. These benefits were also evident for AEx at levels much lower than recommend guidelines and independent of weight loss