Tissue-specific Insulin Resistance in Obstructive Sleep Apnea: Role of Hypoxia

Sixty nondiabetic men and women Inclusion Criteria: * Age \>19 years * BMI \>18.5 kg/m2 * Participants newly diagnosed obstructive sleep apnea (OSA) must meet the criteria for one of the two following groups: * OSA with hypoxia (H-OSA) defined as those with an H-Apnea Hypopnea Index (AHI) ≥15 so as to match the NH-OSA subjects in event frequency and because this is the range defined as more than mild OSA such that we would be likely to see pathology associated with OSA; or, * OSA without hypoxia (NH-OSA) defined as having a rate of non-hypoxic respiratory events ≥ 15 per hour (NH-AHI≥15) and having a rate of hypoxic events of less than 5 per hour (H-AHI\<5,(52)). Exclusion Criteria: * Type 1 or 2 diabetes mellitus currently being treated with medications * History of chronic obstructive pulmonary disease (COPD) or parenchymal lung disease * Unstable hypertension * Treatment for asthma (dependent on type of treatment) * Current alcohol consumption exceeding 1 drink/day in women and 2 in men * HIV infection * Infectious hepatitis * Pregnancy or lactation within the past six months * Irregular use of any hypolipidemic agent * History of surgery for obesity * Hgb below the lower limit of normal * Aspartate transaminase (AST) or alanine transaminase (ALT) greater than 3 times the upper limit of normal * Change in body weight \>5% within preceding 3 months (by self-report)