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

Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormones: insulin and glucagon.

We aim to conduct a randomized two-way cross-over trial comparing single-hormone closed-loop strategy and dual-hormone closed-loop strategy to compare the two interventions during exercise periods in adults with type 1 diabetes. A moderate intensity exercise will be performed for 60 minutes at 60% of the maximum oxygen consumption (VO2max). A high intensity exercise will be 40 minutes of interval training. The interval training will be preceded by a 10 minutes warm-up and followed by a 10 minutes cool down.

Inclusion criteria

• Males and females ≥ 18 years of old.
• Clinical diagnosis of type 1 diabetes for at least one year.
• The subject will have been on insulin pump therapy for at least 3 months.
• Last (less than 3 months) HbA1c ≤ 12%.

Exclusion criteria

• Clinically significant microvascular complications: nephropathy (estimated glomerular filtration rate below 40 ml/min), neuropathy (especially diagnosed gastroparesis) or severe proliferative retinopathy as judged by the investigator.
• Recent (< 3 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.
• Ongoing pregnancy.
• Severe hypoglycemic episode within two weeks of screening.
• Other serious medical illness likely to interfere with study participation or with the ability to complete the exercise periods by the judgment of the investigator (e.g. orthopedic limitation).
• Failure to comply with team's recommendations (e.g. not willing to eat snack, not willing to change pump parameters, etc).
• Problems with venous access