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 (HbA1c), 57 ± 3 mmol·mol (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), physical fitness (+1.7 mL·min·kg), and fat oxidation during exercise in both groups (PTIME < 0.05), with no between-group differences (PTIME × GROUP > 0.05). HbA1c concentrations significantly decreased after exercise training (PTIME < 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%; PTIME × 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. HbA1c seems to be improved more with exercise performed in the postprandial compared with the postabsorptive state.