Exercise-induced Glycemic Variations and Hybrid Closed-loop Systems

Type 1 diabetes is characterized by high risk of hypoglycemia and associated fear of hypoglycemia. Hypoglycemia risk is higher during and after physical activity, especially aerobic activity of long duration. Fear of hypoglycemia can result in avoidance of exercise or overcompensatory eating, both related to worse metabolic control and increased cardiometabolic risk. Hybrid closed-loop (HCL)systems have significantly improved risk of hypoglycemia. They also offer the possibility to set a temporary target for physical activity, further reducing the risk of hypoglycemia during physical activity. Although temporary target seems to work rather well with moderate-intensity aerobic exercise, little data is available for other types of exercise, like resistance exercise, high-intensity interval exercise, combined modalities of exercise, in which the temporary target seems to perform less well. The present study aims to test the performance of current HCL systems under different exercise conditions and evaluate the relationship between different exercise variables (recorded during exercise), physical activity variables (measured by accelerometry) and glycemic variations in HCL system users.

Inclusion Criteria:Age ≥ 18 years and ≤ 65 years oldT1DM duration ≥ 1 year;Automated insulin pump therapy (Hybrid closed-loop) ≥ 12 weeks; HbA1c < 10 %Physically able to complete the study protocolExclusion Criteria:severe diabetic nephropathy, retinopathy and neuropathy;acute cardiovascular events in the last 6 months;presence of diabetic foot ulcers;severe hypoglycemia, diabetic ketoacidosis in the past month;severe visual impairment; systemic steroid therapy;pregnancy;any major life-threatening disease.