Prediabetes is a metabolic condition defined by elevated fasting (impaired fasting glucose (IFG)) and/or postprandial (impaired glucose tolerance (IGT)) glucose. Prediabetes affects nearly 86 million adults in the United States, with most (up to 70%) progressing to type 2 diabetes within as little as one year. Recent studies have indicated that elevated post-prandial glycemia and hypertriglyceridemia are early indicators of prediabetes, and are major risk factors for complications of prediabetes, including cardiovascular disease (CVD), stroke, elevated blood pressure, and obesity. Resistance exercise is a central component of exercise recommendations for individuals with type 2 diabetes and prediabetes, but the effect of resistance exercise on postprandial lipid and glucose metabolism are not known in this population.

In Chapter 2, we examine the effects of a single bout of resistance exercise on post-prandial glucose kinetics, insulin sensitivity, and carbohydrate oxidation after consumption of a mixed meal. Our results suggest that a single session of resistance exercise increases glucose tolerance, reduces post-prandial insulin levels, increases insulin sensitivity and glucose clearance, and increases carbohydrate oxidation.

In Chapter 3, we examine the effects of a single bout of resistance exercise on post-prandial exogenous and endogenous lipid handling and partitioning into plasma chylomicrons, VLDL, and free fatty acids (FFA), as well as lipoprotein kinetics, FFA kinetics, and lipid oxidation. We found that a single session of resistance exercise reduces exogenous and endogenous lipid contributions to circulating lipoprotein and FFA pools, increases lipoprotein turnover, escalates FFA clearance rates, and improves lipid oxidation.

In Chapter 4, we examine the effects of a single bout of resistance exercise on skeletal muscle mitochondrial respiration and the expression of key genes known to regulate lipid and glucose metabolism. We also identify changes the expression of genes known to influence lipid and glucose metabolism in subcutaneous abdominal adipose tissue after the single session of resistance exercise. Our results suggest that a single session of resistance exercise increases skeletal muscle mitochondrial lipid oxidation, coupled respiration, and uncoupled respiration concurrently with increases in the expression of genes that increase lipid oxidation. We also found that genes involved in adipose tissue lipolysis and glyceroneogenesis were significantly up-regulated in adipose tissue after the resistance exercise session.

Overall, these results provide evidence for the beneficial effects of resistance exercise on postprandial glucose and lipid metabolism in obese men with prediabetes after consumption of a mixed meal. Improvements in postprandial lipid and glucose responses could reduce the risk for progression to type 2 diabetes, as well as the risk for complications of prediabetes.