Introduction and purpose: Chronic hyperglycemia in type 2 diabetes mellitus (T2DM) promotes oxidative stress by enhancing the production of reactive oxygen species (ROS) and impairing the endogenous antioxidant defense system. This study aimed to investigate the effects of eight weeks of combined exercise training, with and without gamma-oryzanol supplementation, on oxidative stress markers, total antioxidant capacity, glycemic indices, and insulin resistance in men with T2DM.
Methods: Thirty men with T2DM were purposefully recruited and assigned to three groups (n=10 per group): combined training +placebo (CT+P), combined training + gamma-oryzanol supplementation (CT+S), and control-placebo (C). The training groups performed combined exercise (resistance training at 40–70% of one-repetition maximum [1RM] and endurance training at 50–70% of heart rate reserve [HRR]) for eight weeks, three sessions per week. The supplementation group received 600 mg/day of gamma-oryzanol in two divided doses over the same period. Fasting blood samples were collected 48 hours before and after the intervention to measure serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC), fasting blood glucose (FBG), insulin, and glycated hemoglobin (HbA1c). Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) was calculated accordingly. Data were analyzed using two-way repeated-measures ANOVA followed by LSD post-hoc test, with statistical significance set at P ≤ 0.05.
Results: Significant reductions were observed in FBG, insulin, HOMA-IR, HbA1c and MDA levels in both intervention groups compared to the control group (P < 0.05). Moreover, significant increases were found in SOD (P=0.012) and TAC (P=0.017) levels in the intervention groups versus the control group. However, no statistically significant differences were detected between the CT+P and CT+S groups for any of the measured variables (P > 0.05).
Conclusion: Eight weeks of combined (aerobic-resistance) training improved glycemic indices, insulin resistance, and oxidative stress in men with type 2 diabetes. This improvement was independent of gamma-oryzanol supplementation, as no additional effect was observed when this supplement was added to the training.