Glycemic Responses to Two Different Exercise Modalities in Adolescents with Type 1 Diabetes Using Automated Insulin Delivery Systems: The AIDing Exercise Study

Objective: To examine the glycemic responses to two exercise modalities—high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE)—when applying consensus guideline preexercise preparatory measures in adolescents with type 1 diabetes using automated insulin delivery (AID) systems. Research Design and Methods: In a two-period, crossover trial, 24 individuals (12 using MiniMed™ 780G and 12 using Tandem Control-IQ™) completed two experimental study days involving HIIE and MICE sessions. Participants were matched on age, sex, and total daily dose across AID systems. Continuous glucose monitoring (CGM) and insulin pump data were collected from participants’ AID systems. Plasma glucose (PG) was measured throughout the study days. Exercise was announced 60 min before MICE initiation, but not before HIIE. Results: No significant difference was observed for the primary outcome, CGM-derived time in range (TIR CGM : 3.9–10.0 mmol/L [70–180 mg/dL]), between study visits (HIIE: 91.7 [58.3–100.0] % vs. MICE: 83.3 [75.0–100.0] %, P = 0.261). Participants developed hypoglycemia during both visits (HIIE: 8 vs. MICE 11). When analyzed by the AID system, TIR PG (PG: 3.9–10.0 mmol/L [70–180 mg/dL]) was higher during MICE in the MiniMed™ 780G group, with no difference in the number of participants experiencing hypoglycemia at either visit. Conclusions: When applying consensus guideline preexercise recommendations, both exercise modalities achieved generally stable glycemic outcomes; however, hypoglycemia remained a challenge across study visits. These findings highlight that current AID systems still fall short of ensuring safe glycemic responses during exercise.