ARTIGO ORIGINAL DOI: 10.4025/cienccuidsaude.v17i1.34368 Cienc Cuid Saude 2018 Jan-Mar 17(1) *Physiotherapist.Master in human nutrition, professor of the Faculdade Sete de Setembro, in thesubjectsof of human anatomy and physiology. Paulo Afonso, BA, Brazil. E-mail: rafaell_85@hotmail.com **Doctor.Doctorate in Medicine. Adjunct professor of medicine at the Federal University of Alagoas (UFAL) in the medical clinic department. Maceió, Al, Brazil. E-mail: irrivera@uol.com.br ***Graduated in Physical Education and Physiotherapy. Specialist in Strength training and physical conditioning. Recife, PE, Brazil. E-mail: zirlenebrito@hotmail.com ****Doctor. Doctorate in Medicine. Adjunct professor of medicine andofthemaster'sdegree in HumanNutritionatthe Federal UniversityofAlagoas andFacultyofhumannutrition(UFAL/FANUT). Maceió, Al, Brazil. E-mail: malayde1@uol.com.br EFFECT OF OBESITY ON LUNG PHYSIOLOGY AND DISTURBANCES BEFORE AND AFTER BARIATRIC SURGERY Rafaell Batista Pereira* Ivan Romero Rivera** Zirlene Correia Toscano de Brito*** Maria Alayde Mendonça da Silva**** ABSTRACT This work aims to compare spirometry data before and after bariatric surgery, as well as the frequency of lung disorders. An observational, retrospective and analytical cohort study was performed, through the selection of patients with a diagnosis of obesity and indication of bariatric surgery. The sample size consisted of 28 obese patients, of 23 were women and five were men, to analyze the variables through spirometry, following the ATS protocols, using the best breath of three and selecting the best results curves. After surgery, there was a significant improvement in lung volumes and capacity: Forced vital capacity (FVC), FVC / Forced Expiratory Volume in one second ratio (FVC / FEV1) and Expiratory Flow Peak (EFP) and the Forced Expiratory Volume in one second FEV1, these variables increased significantly. There was also a strong and significant correlation between weight loss and increased FVC / FEV1, and EFP. The Relative Risk for lung disorders was 2.8-fold more likely to develop pulmonary dysfunction in obese than non-obese (post-surgical) patients. Gastroplasty improved lung physiology as well as reduced the frequency of disorders. Keywords: Obesity. Weight loss. Bariatric surgery. Spirometry. Pneumopathies. INTRODUCTION Obesity is characterized by excessive accumulation of body fat in the human body; anatomically, can be classified as hyperplastic and hypertrophic. Hyperplastic obesity is when a person has an abnormally increased number of fat cells. A normal person has about 30 billion adipose cells, while an obese person with hyperplasia may have 42 to 106 billion of these cells. Hypertrophic obesity, in turn, is related to the increase in the size of existing cells, a situation triggered by high caloric intake and sedentary lifestyle (1) . Studies have shown that metabolic changes (dyslipidemia, diabetes mellitus), lung disorders, changes in lung volumes and capacity, obstructive sleep apnea, renal, biliary diseases and certain types of neoplasms, as well as cardiovascular diseases, systemic arterial hypertension and neurological diseases are associated with obesity (1,2) . The clinical treatment of obesity with the use of diet, physical activity and psychotherapy is not always enough to determine the necessary weight loss, especially in severe obese patients. As a treatment strategy, bariatric surgery has become a practicable option for determining great weight loss and body fat, with a significant reduction in obesity- related comorbidities mentioned earlier (2,3) . In Brazil, there are few articles published in recent years evaluating the relationship between obesity and pulmonary functions in patients undergoing bariatric surgery and the risk of obesity associated with pulmonary disorders in patients undergoing spirometry examination, which determined the question that guides the present research: To what extent does severe obesity influence mechanics and, consequently, pulmonary function as well as disorders associated with the respiratory system? The measurement of pulmonary function can be evaluated through spirometry, since it is the examination with greater precision and specificity that detects, in addition to lung volumes and capacity, also the speed with which the air is inspired or expired. In this way, the exam can evaluate the predicted value for each person, as well as monitor the evolution of these parameters after interventions. The interpretation of pulmonary volumes can assess pulmonary physiology, identifying changes in different phases of ventilation and also of forced pulmonary volumes (4) .