Effects of exercise on insulin resistance and body composition in overweight and obese women with and without polycystic ovary syndrome

Context: Polycystic ovary syndrome (PCOS) is an insulin-resistant (IR) state. Visceral fat (VF) is independently associated with IR. Objectives: The objectives of the study were to explore mechanisms underpinning IR by assessing the effect of exercise training on IR and body composition in overweight PCOS and non-PCOS women. Design: This was a prospective exercise intervention study. Setting and Participants: The study was conducted at an academic medical center. Participants included 20 overweight PCOS and 14 overweight non-PCOS women. Intervention: The intervention included 12 wk of intensified aerobic exercise (3 h/wk). Main Outcome Measures: IR on euglycemic hyperinsulinemic clamp, body composition including abdominal visceral and sc fat distribution by computer tomography and lipids was measured. Results: PCOS subjects were more IR (P = 0.02) and had more VF (P = 0.04 age adjusted) than non-PCOS women. In PCOS women, IR correlated with VF (r = -0.78, P <0.01). With exercise training, both groups maintained weight but within PCOS, VF (-12.0 cm(2), P = 0.03) and within non-PCOS abdominal sc fat (-40.2 cm(2), P = 0.02) decreased. Despite exercise-induced improvement in IR within PCOS (+27.9 mg 1 m(-2) 1 min(-1), P = 0.03), no relationship with decreased VF (r = -0.08, P = 0.84) and no differential changes in IR and VF between groups were noted. Triglycerides decreased within PCOS (-0.27 mmol/liter, P = 0.02) and decreased differentially between groups (P <0.01).