Timing of Exercise Affects Glycemic Control in Type 2 Diabetes Patients Treated with Metformin

OBJECTIVE: The purpose of the study was to examine the acute effects of the timing of exercise on the glycemic control during and after exercise in T2D. METHODS: This study included 26 T2D patients (14 women and 12 men) who were treated with metformin. All patients were tested on four occasions: metformin administration alone (Metf), high-intensity interval training (HIIT) performed at 30 minutes (EX30), 60 minutes (EX60), and 90 minutes (EX90) postbreakfast, respectively. Glucose, insulin, and superoxide dismutase (SOD) activity were examined. RESULTS: Glucose decreased significantly after the exercise in EX30, EX60, and EX90. Compared with Metf, the decline in glucose immediately after the exercise was larger in EX30 (−2.58 mmol/L; 95% CI, −3.36 to −1.79 mmol/L; p < 0.001), EX60 (−2.13 mmol/L; 95% CI, −2.91 to −1.34 mmol/L; p < 0.001), and EX90 (−1.87 mmol/L; 95% CI, −2.65 to −1.08 mmol/L; p < 0.001), respectively. Compared with Metf, the decrease in insulin was larger in EX30 and EX60 (both p < 0.001). CONCLUSIONS: Timing of exercise is a factor to consider when prescribing exercise for T2D patients treated with metformin. This trial is registered with ChiCTR-IOR-16008469 on 13 May 2016.