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.