A Randomized Crossover Pilot Study Evaluating Glucose Control During Exercise Initiated 1 or 2 h After a Meal in Adults with Type 1 Diabetes Treated with an Automated Insulin Delivery System

Aims: To assess the safety and efficacy of two exercise sessions performed 60- and 120-min postmeal with a combination of meal bolus reduction and increased glucose target to the automated insulin delivery (AID) system.Methods: A randomized crossover trial in 13 adult participants (6 females) living with type 1 diabetes using AID (A1c = 7.9% +/- 0.6%, age = 53.5 +/- 15.5 years, T1D duration = 29.0 +/- 16.0 years) was conducted. Just before breakfast, at the time of meal bolus, the AID glucose target was increased from 6 to 9 mmol/L, and a meal bolus reduction of 33% was applied. Two 60-min exercise sessions (60% of VO2 peak) were undertaken either 60 min (60EX) or 120 min (120EX) after a standardized breakfast, followed by a 90-min recovery period.Results: The mean reduction in plasma glucose (PG) levels from prebreakfast to postexercise (-0.8 +/- 2.4 mmol/L vs. +0.3 +/- 2.3 mmol/L, P = 0.082) were similar between 60EX and 120EX. From prebreakfast to postexercise, PG times in range (3.9-10.0 mmol/L; 63.4% +/- 43.1% 60EX vs. 51.9% +/- 29.7% 120EX, P = 0.219) and time above range (>10.0 mmol/L; 36.3% +/- 43.3% 60EX vs. 48.1% +/- 29.7% 120EX, P = 0.211) did not differ between interventions. The 60EX attenuated the glucose rise between premeal to pre-exercise (+1.8 +/- 2.1 mmol/L 60EX vs. +3.9 +/- 2.1 mmol/L 120EX, P = 0.001). No hypoglycemic events (<3.9 mmol/L) occurred during the study.Conclusion: Premeal announcement combining meal bolus reduction and increased glucose target was effective and safe during 60 min of moderate-intensity aerobic exercise, whether exercise onset was 60 or 120 min following a meal.

Automated summary

This study aimed to assess the safety and efficacy of combining meal bolus reduction and increased glucose target in the automated insulin delivery (AID) system for exercise sessions performed 60- and 120-min postmeal. The results showed that this method was effective and safe during moderate-intensity aerobic exercise, regardless of whether the exercise was performed 60 or 120 min after a meal.