Pre-exercise blood glucose affects glycemic variation of aerobic exercise in patients with type 2 diabetes treated with continuous subcutaneous insulin infusion

Aims: Considering the insulin sensitivity may increase by exercise particularly in patients with type 2 diabetes (T2D), glycemic variation during exercise needs to be studied when the patients are treated with insulin. This study aimed to explore the influence factors of the efficacy and safety of aerobic exercise in patients with T2D treated with Continuous Subcutaneous Insulin Infusion (CSII).

Methods: A total of 267 patients with T2D, treated with CSII, were included. Glycemic variations were assessed by continuous glucose monitoring (CGM). Patients were asked to complete 30 min aerobic exercise for at least one time during CGM. The patients were divided into effective and ineffective group by incremental glucose area under curve from 0 to 60 min after exercise (AUC_{0-60 min}).

Results: The patients completed a total of 776 times of aerobic exercises. Blood glucose decreased fastest in the first 60 min of exercise. Pre-exercise blood glucose (PEBG) was negatively correlated with AUC_{0-60 min} (standardized β = -0.386, P < 0.001) and incremental AUC of blood glucose ≤ 4.4 mmol/L (standardized β = -0.078, P = 0.034), and was significantly higher in effective group than in ineffective group (P < 0.001). The Δglucose AUC_{0-60 min} during post-dinner was significantly higher than that during pre-lunch, post-lunch and pre-dinner (P < 0.05 for all).

Conclusions: PEBG is positively correlated with efficacy of aerobic exercise. Aerobic exercise will not worsen hyperglycemia when the PEBG > 16.7 mmol/L. Post-dinner exercise decreases the blood glucose better than other periods of the day.

Clinical trials registration: ChiCTR-ONC-17010400, www.chictr.org.cn.