Context: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular morbidity. Recurrent episodes of occlusion of upper airways during sleep result in hormonal changes that may predispose to high cardiovascular risk.These risks can rapidly be reduced by effective nasal continuous positive airway pressure (nCPAP) therapy Objective: To evaluate hypothalamic pituitary adrenal axis, insulin resistance, blood pressure values and adipokines in severe obese patients with and without OSAS and to determine if continuous positive airway pressure therapy (nCPAP) influenced responses.