Safely finishing a half marathon by an adult with type 1 diabetes using a commercially available hybrid closed-loop system.

Glycemic targets are often difficult to achieve in people with type 1 diabetes, especially during exercise. Consequently, many people with type 1 diabetes avoid sports as a result of fear of hypoglycemia. Strenuous physical activity, such as a half marathon, imposes difficulties on people with type 1 diabetes. The first commercial hybrid closed-loop (HCL) system with the potential to facilitate better diabetes management during exercise has recently been marketed. So far, no data on HCL performance during strenuous exercise have been published. A woman with well-controlled type 1 diabetes participated in and safely finished a half marathon while undergoing HCL therapy. HCL could safely establish glycemic control without causing either hypo- or relevant hyperglycemia, and without the need for rescue carbohydrates while running. In the days after the half marathon, there was no change in glycemic control compared with the period before.