The objective of this study is to investigate if the addition of a 12-week program of home-based high intensity interval training to a standard educational program aiming at preventing hypoglycemia episodes will restore hypoglycemia awareness in people living with type 1 diabetes and impaired awareness of hypoglycemia to a further extent than a standard educational program alone.

Participants will be randomized for 12 weeks to the standard educational program with or without high intensity interval training. The Gold method will be used to identify people with impaired awareness of hypoglycemia.

The educational program will consist of two education sessions on avoidance of hypoglycemia, causes of hypoglycemia, treatment (e.g. glucagon) of hypoglycemia, how to better recognize hypoglycemia symptoms, understand how to use a CGM/Flash-GM and understand CGM/Flash-GM reports to adjust insulin doses.

Participants randomized to the training program will be asked to train three times per week for 12 weeks following the home-based program that will be provided to them. Participants will be asked to perform at least 2 training sessions per week (ideally all 3 sessions) with the exercise specialist on a virtual platform.

Inclusion Criteria:

1. Males and females aged between 18 and 65 years old.
2. Clinical diagnosis of type 1 diabetes for at least five years.
3. Treatment with multiple daily insulin injections or insulin pump therapy and using insulin analogs (rapid, ultra-rapid or basal). The type of insulin should be stable for at least 1 month. Participants not using an insulin analog will be offered the opportunity to switch to an insulin analog and this will be done at least 1 month before inclusion.
4. Impaired awareness of hypoglycemia (Gold score ≥ 4).
5. HbA1c ≤ 10%
6. Using a continuous glucose monitor or being willing to start using one for the study
7. Having an electronic device supporting the Polar Beat application (heart rate monitor).

Exclusion Criteria:

1. Clinically significant microvascular complications: nephropathy (estimated glomerular filtration rate below 40 ml/min), neuropathy (especially advanced peripheral neuropathy with significantly lower limb reduced proprioceptive perception) or severe proliferative retinopathy as reported by the patient and/or judged by the investigator.
2. High risk foot problem (e.g., previous amputation, history of foot wound, known severe neuropathy or peripheral arterial disease)
3. Recent (< 3 months) acute macrovascular event e.g., acute coronary syndrome or cardiac surgery or history of significant heart disease.
4. Known significant cardiac rhythm abnormality based on investigator judgment.
5. Abnormal blood panel and/or anemia (Hb < 100g/L).
6. Ongoing pregnancy or breastfeeding.
7. Severe hypoglycemic episode or diabetic ketoacidosis within 1 month of screening.
8. Uncontrolled hypertension (blood pressure >160/100 mm Hg).
9. Uncontrolled angina.
10. Treatment with oral steroids within the last 3 months.
11. History of significant lung disease that would limit exercise.
12. Seizure within the last 3 months.
13. Participation in high-intensity interval training (or equivalent) in the past 6 months.
14. Physical ability preventing the completion of the 12-week training program (e.g., orthopedic limitation).
15. Inability to give consent.