Obesity's effect on muscle insulin action and cardiorespiratory fitness in type 1 diabetes
Impact of Obesity on Microvascular Insulin Action and Cardiorespiratory Fitness in Type 1 Diabetes (
This will see if muscle insulin resistance and excess weight are linked to lower cardio fitness in adults with type 1 diabetes compared with healthy controls before and after a high-intensity interval training program.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 60 (estimated) |
| Ages | 21 Years to 50 Years |
| Sex | All |
| Sponsor | University of Virginia Academic / other |
| Locations | 1 site (Charlottesville, Virginia) |
| Trial ID | NCT07573228 on ClinicalTrials.gov |
What this trial studies
Researchers will compare adults with type 1 diabetes (with and without obesity) to matched healthy controls, measuring muscle microvascular insulin responsiveness and cardiorespiratory fitness before and after a supervised high-intensity interval training (HIIT) program. The protocol includes baseline and post-training physiological testing, measures of muscle oxidative stress, mitochondrial function, capillary density, and satellite cell counts to explore mechanisms. Participants are adults aged 21–50 with defined BMI ranges and stable diabetes management, and the intervention is structured exercise training with pre/post tissue and vascular assessments. The design tests whether obesity worsens microvascular insulin resistance and whether that predicts declines in fitness that can be modified by HIIT.
Who should consider this trial
Good fit: Ideal candidates are adults 21–50 years old with type 1 diabetes for at least 5 years and HbA1c ≤8.5% on multiple daily injections or an insulin pump (or healthy controls), fitting the study's specified BMI categories and without major comorbidities.
Not a fit: People with active chronic diseases other than type 1 diabetes, a history of diabetes complications, recent diabetic ketoacidosis, hypoglycemia unawareness, or those outside the age/BMI limits are unlikely to benefit or qualify.
Why it matters
Potential benefit: If successful, the study could clarify mechanisms linking obesity and microvascular insulin resistance to reduced fitness in type 1 diabetes and support targeted exercise or weight-management strategies to improve fitness.
How similar studies have performed: Previous exercise trials, including HIIT, have reliably improved cardiorespiratory fitness and whole-body insulin sensitivity, but the specific role of muscle microvascular insulin resistance in type 1 diabetes is less well established and relatively novel.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * • 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 Criteria: * • 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%
Where this trial is running
Charlottesville, Virginia
- University of Virginia — Charlottesville, Virginia, United States (Recruiting)
Study contacts
- Principal investigator: Zhenqi Liu, MD — University of Virginia
- Study coordinator: Lee Hartline, MEd
- Email: lmh9d@virginia.edu
- Phone: 434-924-5247
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.