Moderate-intensity endurance training improves late phase β-cell function in adults with type 2 diabetes

Physical activity is important for type 2 diabetes treatment, yet the underlying mechanisms for these beneficial effects of exercise are not fully understood. Here, we investigated the effects of exercise training on biphasic β-cell insulin secretory function, a key factor regulating blood glucose. Adults with type 2 diabetes (7F/3M, age 49 ± 5 years, BMI 30 ± 3 kg/m²) completed a 10-week moderate-intensity exercise program and multiple components of glucose homeostasis were measured. Training improved glycemic control, insulin sensitivity, and processing of proinsulin-to-insulin. Training increased late phase β-cell function by 38% (p = 0.01), which was correlated with changes in VO_2peak suggesting training response-dependent effects. Ras-Responsive Element Binding Protein 1 (RREB1) concentrations, a protein postulated to increase type 2 diabetes risk, were inversely correlated with increases in training-induced late-phase disposition index, consistent with an inhibitory role of RREB1 on insulin secretion. Moderate-intensity exercise training improves late-phase β-cell function and glycemic control in adults with type 2 diabetes.