Blood Glucose Target Before and During Exercise in Adults With Type 1 Diabetes Using an Artificial Pancreas

Despite major technological advances in type 1 diabetes (artificial pancreas), the management of hypoglycemia remains a major challenge, especially during and after physical activity. The primary outcome is to determine the temporary blood glucose (BG) target to be set 60 minutes before aerobic exercise in people with type 1 diabetes (PWT1D) using do-it-yourself automated insulin delivery (DIY-AID) systems. Three glycemic thresholds to be applied 60 minutes before physical activity will be tested in 32 people on AID-DIY: 8.3 (current target for commercial AID systems), 8.8, and 9.3 mmol/L. Each participant will perform 3 sessions of moderate aerobic physical activity (ergocycle) at 60% of vo2peak with a different glycemic target each time (random order). Plasma glucose will be measured every 20 minutes before and during physical activity, and blood glucose measured by continuous glucose reading (DEXCOM) for 24 hours post-intervention. Once the best glycemic target is selected, participants could come to the research center for 1 or 2 more voluntary interventions to test the threshold during 1) fasting exercise and 2) late luteal phase of the menstrual cycle.