The purpose of this study is to compare three different therapeutic and nutritional approaches during a prolonged aerobic exercise in moderately active type 1 diabetes people using advanced technologies, to identify the best strategy for the management of this type of exercise. Participants will be randomly assigned to different interventions in three different occasions: insulin therapy adjustment; nutritional adjustment; combination of insulin and nutritional adjustment.

Regular exercise is recommended in people with type 1 diabetes (T1D) for its several health benefits (increased cardiovascular fitness, greater muscle strength, improved insulin sensitivity). However, therapeutic, and nutritional management of physical exercise is complex due to the multiple intra- and interindividual factors influencing glycemic response to exercise in T1D people. Glucose levels can increase, stay stable, or decrease depending on the type, duration, and intensity of exercise. During prolonged aerobic exercise, there is an increase in the risk of hypoglycemia also in patients using advanced technologies such as the hybrid artificial pancreas (HAP). The HAP consists of a continuous glucose monitoring (CGM) sensor and an insulin pump connected by a control algorithm that infuses insulin based on the glucose value recorded by the CGM sensor. With HAP there is the possibility to set a higher glucose target to make the insulin doses less aggressive during a scheduled session of physical exercise thus reducing the risk of hypoglycemia. However, there are different approaches, including insulin therapy adjustments or consumption of carbohydrates, proposed to minimize glycemic excursions during prolonged aerobic exercise in patients with T1D. Currently, the best strategy to manage physical exercise in people with type 1 diabetes on HAP, is not defined.

So, the aim of this study is to identify the optimal strategy for the management of prolonged aerobic exercise in moderately active T1D patients using hybrid artificial pancreas treatment. The exercise consists of an outdoor walk of 10 km over 4 hours and a height difference of 200-300 m. Each participant will be randomly assigned to three different therapeutic and nutritional interventions on three different occasions: 1)Target, which consists in setting a higher glucose target from 1 hour before until the end of the walk; 2) Snack, which consists of the consumption of 15 g of complex carbohydrates as whole grain crackers every 30 minutes, during the 4 hours of the walk; 3) Target+Snack consists in the combination of both Target and Snack interventions. Glycemic control expressed as CGM metrics and insulin doses delivered by HAP during the 4 hours of walks will be assessed.

Inclusion Criteria:

• Type 1 diabetes
• Using of hybrid artificial pancreas

Exclusion Criteria:

• Health conditions that may affect the safe performance of physical activity
• Pregnancy