Impact of Exercise–Nutritional State Interactions in Patients with Type 2 Diabetes

ABSTRACT Introduction This study examines the role of nutritional status during exercise training in patients with type 2 diabetes mellitus by investigating the effect of endurance-type exercise training in the fasted versus the fed state on clinical outcome measures, glycemic control, and skeletal muscle characteristics in male type 2 diabetes patients. Methods Twenty-five male patients (glycated hemoglobin (HbA1 c ), 57 ± 3 mmol·mol −1 (7.4% ± 0.3%)) participated in a randomized 12-wk supervised endurance-type exercise intervention, with exercise being performed in an overnight-fasted state ( n = 13) or after consuming breakfast ( n = 12). Patients were evaluated for glycemic control, blood lipid profiles, body composition and physical fitness, and skeletal muscle gene expression. Results Exercise training was well tolerated without any incident of hypoglycemia. Exercise training significantly decreased whole-body fat mass (−1.6 kg) and increased high-density lipoprotein concentrations (+2 mg·dL −1 ), physical fitness (+1.7 mL·min −1 ·kg −1 ), and fat oxidation during exercise in both groups ( P TIME < 0.05), with no between-group differences ( P TIME × GROUP > 0.05). HbA1 c concentrations significantly decreased after exercise training ( P TIME < 0.001), with a significant greater reduction after consuming breakfast (−0.30% ± 0.06%) compared with fasted state (−0.08% ± 0.06%; mean difference, 0.21%; P TIME × GROUP = 0.016). No interaction effects were observed for skeletal muscle genes related to lipid metabolism or oxidative capacity. Conclusions Endurance-type exercise training in the fasted or fed state do not differ in their efficacy to reduce fat mass, increase fat oxidation capacity, and increase cardiorespiratory fitness and high-density lipoprotein concentrations or their risk of hypoglycemia in male patients with type 2 diabetes. HbA1 c seems to be improved more with exercise performed in the postprandial compared with the postabsorptive state.