Closed-loop Control of Glucose Levels (Artificial Pancreas) During Postprandial Exercise in Adults With Type 1 Diabetes

Patients will be admitted at the research clinical facility at 6:30. The artificial pancreas intervention will start at 7:00. A standardized breakfast will be served at 8:00. At 9:30, patients will performed a 60-minute exercise on the ergocycle at 60% of VO2 max. At 11:30, patients will be switched to standard insulin pump therapy and a lunch will be served. Patients will be discharged after lunch consumption.

Patient's insulin pump will be used to infuse insulin.

The Dexcom G4 Platinum glucose sensor will be used to measure glucose levels.

Patient's usual fast-acting insulin analog will be used.

Variable subcutaneous insulin infusion rates will be used to regulate glucose levels. Patient's usual fast acting insulin analog (Lispro, Aspart or Guilisine) will be infused using the patient's pump. The glucose level as measured by the real time sensor (Dexcom G4 Platinum, Dexcom Inc.) will be entered manually into the computer every 10 minutes. The pump's infusion rate will then be changed manually based on the computer generated recommendation infusion rates.