Inclusion Criteria:  Type 1 diabetes for ≥ 2 years and negative C-peptide (<100pmol/l) Male and female aged 18-65 years old HbA1c <9% (at least two values in a row in the past year), based on analysis from the central laboratory unit of Ghent University Hospital. Insulin treatment: multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII): insulin pump alone without connection to sensor, or sensor-augmented pump (SAP) with or without stop at/before low; however no hybrid closed-loop systems will be included). Able to understand study instructions and to provide written informed consent.  Exclusion Criteria:  Physical or psychological disease likely to interfere with the normal conduct of the study as judged by the investigator. Body mass index >= 35 kg/m2. Self-monitoring of blood glucose (SBMG) with finger prick CSII with a hybrid closed-loop insulin pump Taking any medication that affects heart rate. Current treatment with drugs known to interfere with metabolism, e.g. systemic corticosteroids, SGLT2 inhibitors, glucagon-like-peptide 1 (GLP-1) receptor agonists, or metformin. Hypoglycaemic unawareness (Gold score ≥4) or having experienced any episode of a severe hypoglycaemic event within the last 6 months (i.e. need of third-party assistance). Known coronary or cerebral artery disease, i.e. history of angina pectoris, myocardial infarction (MI), stroke or any cardiovascular procedure. Severe non-proliferative and unstable proliferative retinopathy, based on medical record. Severe diabetic peripheral neuropathy (DPN) or autonomic neuropathy, based on medical record. Uncontrolled hypertension (>180/100 mmHg). Pregnant or planning to become pregnant during the study period (females) Breastfeeding (females).