Effects of Walking and Unilateral Leg Heating on Vascular Function in Diabetic Patients

The notion that habitual aerobic exercise increases insulin-induced vasodilation is largely
founded on rodent studies, hence the urgent need for human studies, especially in patients
with type 2 diabetes (T2D). For example, it remains unknown if increased walking, the most
common form of physical activity, enhances skeletal muscle vasodilator actions of insulin in
T2D. In addition, the molecular mechanisms by which exercise improves vasoreactivity to
insulin have not been examined in humans. The investigators propose that in T2D patients who
are sedentary (i.e., the vast majority), increased leg blood flow with walking or local
heating signifies a vital strategy to correct vascular insulin resistance. This study will
establish whether increased physical activity and associated hemodynamic forces (e.g., shear
stress) are a direct form of vascular medicine in humans.

Inclusion Criteria:

Patients with type 2 diabetes who are overweight and obese (BMI 25-39 kg/m2), 35 to 65
years of age, and sedentary (<60 minutes structured exercise/week). Healthy volunteers
without type 2 diabetes: 18 to 65 years of age.

Exclusion Criteria:

1. Cardiovascular disease including myocardial infraction, heart failure, coronary artery
disease, stroke;

2. renal or hepatic diseases;

3. active cancer;

4. autoimmune diseases;

5. immunosuppressant therapy;

6. excessive alcohol consumption (> 14 drinks/week);

7. current tobacco use;

8. pregnancy;

9. mobility limitations.