Obesity is a major public health problem in developed and developing countries, causing a range of respiratory and metabolic changes. There is a strong correlation between obesity and cardiorespiratory sleep disorders. The weight loss reduces the comorbidities and improves the quality of life, but clinical treatment it is not effective for a long period. In this context, currently bariatric surgery is an option for the real weight loss in the long term. Obstructive sleep apnea (OSA) is a common clinical condition observed in patients with obesity. The primary aim of this protocol are to assess the inflammatory profile of severe obese patients undergone to bariatric surgery, through systemic and adipose markers of inflammation. A secondary objective is study the impact of this surgery on sleep variables and quality of life. Investigators hypothesized that weight loss induced by bariatric surgery reduces systemic inflammatory profile, improve sleep quality and quality of life of subjects with severe obesity. Will participate in this study, patients with severe obesity (BMI > 40 or 35 to 39.9 kg/m2 associated comorbidities), with indication of bariatric surgery, screened Bariatric Surgery Service of Santa Casa de São Paulo in São Paulo. Inclusion criteria are severely obese, bariatric surgery indication and agreement to participate in the study. Are excluded patients with BMI > 55 kg/m2, clinical instability, mental instability or significant and unrealistic expectations of surgery. Patients will be assessed before and after bariatric surgery, 90, 180 and 360 days. The evaluation protocol will consist of clinical history, vital signs, neck and waist circumference, clinical analysis of blood inflammatory markers, lung function tests, maximal ventilatory pressures, full overnight standard polysomnography, excessive daytime sleepiness scale, cardiovascular risk, quality of life and personal satisfaction questionnaires.