Plasma Triglyceride Extraction by The Muscle

Inclusion Criteria: * Body mass index (BMI): \< 25 kg/m2 or \> 30 kg/m2; * Insulin sensitivity index (ISI): insulin-sensitive ISI ≥ 7, insulin-resistant ISI ≤ 5. Exclusion Criteria: * Medication or supplements known to affect either endothelial function or lipid metabolism (i.e. arginine, protein, fish oil) * Acute illness * Uncontrolled metabolic disease, including liver or renal disease * Atrial fibrillation, history of syncope, limiting or unstable angina, congestive heart failure, known or suspected right-to-left, bi-directional or transient right-to-left cardiac shunts * Cardiac pacemaker or other medical device implanted in the body * Pulmonary hypertension or other unstable cardiopulmonary conditions * ECG documented abnormalities or valvular disease * Low hemoglobin or hematocrit (i.e., lower than accepted laboratory values) * History of hypertension or elevated blood pressure (systolic, \>140 mmHg or a diastolic, \>95 mmHg) * History of hyperlipidemia or plasma triglyceride concentration \>200 mg/dl * Diagnosed diabetes, or 2-h plasma glucose \>200 mg/dl during an oral glucose tolerance test * Current participation in a weight-loss regimen, including extreme dietary practices * Use of anabolic steroids or corticosteroids (within 3 months)