The objective of the study is to evaluate whether pre-exercise administration of low-dose subcutaneous glucagon prevents or attenuates exercise-induced declines in plasma glucose concentration during and after moderate-intensity continuous exercise (MICE) performed approximately 90 minutes after a meal in adults with type 1 diabetes using an automated insulin delivery (AID) system.

The primary endpoint is the difference in the change in plasma glucose (PG) from exercise initiation to the nadir during exercise and through the 2-hour post-exercise period between the glucagon (GCN) and carbohydrate (CHO) visits.

This is a randomized, non-blinded, two-period crossover study including 18 adults with type 1 diabetes using an EU-approved automated insulin delivery (AID) system. Each participant will attend one screening visit followed by two experimental visits performed in random order, separated by at least seven days.

Eligible participants are adults (≥18 years) with type 1 diabetes for at least 2 years, using an automated insulin delivery system for ≥3 months, treated with NovoRapid or Fiasp for at least 1 week prior to enrollment, and proficient in carbohydrate counting.

At each experimental visit, participants will perform a standardized bout of MICE approximately 90 minutes after a meal. On one visit, a low-dose glucagon injection will be administered immediately before exercise; on the other, 20 g oral glucose tablets will be consumed. Right before exercise, the AID system's higher glucose target/exercise mode will be activated and will remain active until 15 minutes after exercise.

Inclusion Criteria:

• Age ≥ 18 years
• Type 1 diabetes ≥ 2 years
• Using an automated insulin delivery system for ≥ 3 months
• NovoRapid or Fiasp use ≥1 week
• Proficiency in carbohydrate counting

Exclusion Criteria:

• Allergies to lactose or glucagon
• Known or suspected allergies to glucagon or related products
• History of hypersensitivity or allergic reaction to glucagon or lactose
• Patients with diagnosed pheochromocytoma, insulinoma or gastroparesis
• Concomitant medical or psychological conditions identified through review of medical history, physical examination and clinical laboratory analysis that, according to the investigator's assessment, makes the individual unsuitable for study participation
• Lack of compliance with key study procedures at the discretion of the investigator
• Females of childbearing potential who are pregnant, breast-feeding or intend to become pregnant or are not using adequate contraceptive methods (methods are considered adequate for study enrolment for females: an intrauterine device, hormonal contraception (birth control pills, implant, patch, vaginal ring or injection), a single partner who is sterile or infertile, or sexual abstinence. Contraception is required throughout the study duration. Sterilized or postmenopausal women (>12 months since last period) are not required to use contraception)
• Inability to understand the individual information and to give informed consent