Impact of Obesity on Microvascular Insulin Action and Cardiorespiratory Fitness in Type 1 Diabetes
Impact of Obesity on Microvascular Insulin Action and Cardiorespiratory Fitness in Type 1 Diabetes (
University of Virginia
60 participants
Feb 23, 2026
INTERVENTIONAL
Conditions
Summary
The purpose of this study is: * To see if insulin resistance (how sensitive your muscle tissue is to insulin) is associated with lower cardio fitness in people with Type 1 diabetes compared to healthy controls, before and after a High Intensity Interval Training (HIIT) exercise program. * To see if being overweight and having Type 1 diabetes is associated with lower cardio fitness compared to overweight healthy controls, before and after a HIIT exercise program.
Eligibility
Inclusion Criteria4
- Male or female ≥21 and ≤50 years old
- For persons with T1D: Disease duration ≥ 5 years and HbA1c ≤ 8.5% on multiple daily insulin injection or insulin pump
- Body mass index: ≥19 and ≤27 kg/m2 for control and T1D, ≥30 and ≤40 kg/m2 (27.5 to 37.5 for Asian Americans) for obesity and T1D + obesity. BMI is limited to ≤40 kg/m2 (37.5 for Asian Americans) for easier vascular access and cardiac imaging.
- Stable use of non-insulin medications for over 6 months other than estrogen/progesterone containing medications which must be discontinued at least 3 months prior to the study (intrauterine devices may be continued due to limited systemic absorption)
Exclusion Criteria14
- Acute or chronic disease other than T1D or obesity
- History of microvascular or macrovascular diabetes complications
- History of diabetic ketoacidosis in the past 24 months
- History of hypoglycemia unawareness
- Recently active (>20 min of moderate/high intensity exercise, 2 times/week)
- Subjects who are smokers or who have quit smoking <5 years
- Subjects with hypertriglyceridemia (>400 mg/dl)
- Current use of vasoactive medications (i.e. calcium channel blockers, angiotensin-converting enzyme or renin inhibitors, angiotensin-receptor blockers, nitrates, alpha- or beta-blockers, or diuretics).
- Females taking oral contraceptives in the past 3 months
- Subjects with a history of significant metabolic, cardiac, cerebrovascular, hematological, pulmonary, gastrointestinal, liver, renal, or endocrine disease or malignancy
- Pregnant (as evidenced by positive pregnancy test) or nursing women
- Musculoskeletal condition preventing participation in exercise testing or exercise training
- History of gastroparesis
- Pulse oximetry <90%
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Interventions
15 weeks of HIIT exercise training
Locations(1)
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NCT07573228