Inclusion Criteria:

• Men and women (21-60 years of age) good health, stable weight, and without any contraindication to exercise.

Exclusion Criteria:

• Anemia (Hct<34%)
• Elevated liver enzyme (25% above normal),
• Proteinuria,
• Hypothyroidism (sTSH > 8)
• Hypertension (blood pressure > 150 mmHg systolic, or > 95 mmHg diastolic)
• Diabetes mellitus (fasting glucose ≥ 126 mg/dl)
• A history of myocardial infarction or peripheral vascular disease
• Liver disease
• Alcohol or drug abuse
• Malignancy or neuromuscular disease
• Subjects will be excluded if taking chronic medications known to adversely affect glucose homeostasis (oral glucocorticoids, nicotinic acid)
• Females currently on hormone replacement therapy (HRT) can participate in the study if they have been on HRT for at least 6 months and will continue to be on HRT during the study.

• Disqualifying findings on physical examination include:

  • Lower extremity thrombophlebitis
  • Evidence of peripheral neuropathy, paresis or edema.

If the resting EKG prior to the exercise test shows any abnormalities, the test will not be conducted. If any abnormalities develop during the test, the test will be stopped. On both occasions, the participant will be referred to their PCP for further evaluation and will only be allowed to continue the study with written clearance by his/her PCP or cardiologist. American College of Sports Medicine (ACSM) criteria will be used to halt maximal exercise testing should adverse cardiovascular responses develop. Only after a cardiologist interprets the resting and exercise ECG of the participant and clears them for exercise, will subjects be able to continue with the study