Using a Personalized Decision Support Tool to Help People With Type 1 Diabetes Manage Exercise

Prior treatment

• Intercurrent illness or medical condition that precludes safe participation in moderate-intensity exercise (e.g., unstable cardiopulmonary disease, uncontrolled arrhythmia, or uncontrolled hypertension), as previously assessed by the participant's primary care physician
• Concurrent participation in another interventional drug or device study within 30 days prior to enrollment
• Use of medications with potential to substantially affect glycemia (e.g., SGLT-2 inhibitors, GLP-1 receptor agonists, or GIP agonists), unless on a stable regimen with no planned changes during the study
• Use of systemic corticosteroids within 4 weeks prior to participation
• History of severe hypoglycemia (requiring third-party assistance) or diabetic ketoacidosis within the prior 6 months

Other illness

• Known coronary artery disease with symptoms limiting moderate physical activity, or history of myocardial infarction, percutaneous coronary intervention, or coronary artery bypass grafting within the past 12 months
• Inability to comply with study procedures or safety requirements (e.g., inability to achieve target heart-rate zone, attend scheduled visits, or enable required device data access), or otherwise deemed unsuitable by the investigator

Lab values

• Renal insufficiency with estimated GFR \<45 mL/min/1.73 m², dialysis dependence, or adrenal insufficiency

Other

• Pregnancy, lactation, or plans to become pregnant during the study period
• Use of non-CSII insulin delivery, including long-acting injectable or inhaled insulin, during the study period

• Adults between the age of 18-60 years
• Able to perform moderate intensity walking for 60 minutes (target 40-60% age-predicted maximal heart rate).
• Willing and able to comply with study procedures, including supervised exercise visits and device wear
• Able to provide written informed consent
• Clinical diagnosis of type 1 diabetes for \>1 year, based on the investigator's clinical judgement
• Current use of continuous subcutaneous insulin infusion with Tandem Control-IQ and a compatible continuous glucose monitor (CGM) for \>1 month prior to enrollment
• Stable insulin delivery regimen, with no planned changes to insulin pump settings or insulin dosing strategy during the study period
• Consistent CGM use during the month prior to enrollment (\>80% data availability)
• No diagnosis of diabetes or other disorders of glucose metabolism
• Not using insulin or glucose-lowering medications