71 participants were enrolled; 41 with PCOS and 30 without. Inclusion criteria: female sex, obesity (BMI percentile >95%) and sedentary status (<3 hours of exercise/week; validated with both a 3 day activity recall and 7 day accelerometer use). Exclusion criteria: diabetes, alanine transferase (ALT) >80 IU/mL, BP >140/90 mmHg, hemoglobin <9mg/dl, serum creatinine >1.5 mg/dl, smoking, medications affecting IS (oral steroids, metformin, thiazolidinediones, atypical antipsychotics, hormonal contraceptives), antihypertensive medications, statins, pregnancy, and breastfeeding. PCOS was diagnosed per NIH criteria with adolescent adaptation: oligomenorrhea (<8 menses a year), clinical or biochemical signs of hyperandrogenism, and at least 2 years post-menarche (8 (link)). The study was approved by the University of Colorado AMC Institutional Review Board. Informed consent was obtained from all participants 18–20 years old, and parental consent and participant assent from all participants <18 years old.