Função pulmonar, força muscular respiratória e capacidade funcional de exercício em indivíduos obesos com apneia obstrutiva do sono

Abstract

Obesity is a chronic disease characterized by the excessive accumulation of body fat due to the difference between consumption and energy expenditure. It presents a multifactorial etiology and is associated with other comorbidities, such as hypertension, diabetes mellitus, atherosclerosis, and Obstructive sleep apnea (OSAS). OSAS is considered a chronic, progressive and incapacitating disease with high morbidity and mortality. The respiratory musculature of individuals with OSAS is affected due to obstructive events. These individuals exhibit decreased upper airway muscle activity and repetitive inspiratory efforts against the obstructed airway. Obesity associated with OSAS increases the risk of collapse of the upper airways during sleep, which alters the functioning of the respiratory system and also interferes with the functional capacity of the individual. The objective of this study was to correlate lung function and inspiratory muscle strength with exercise tolerance in obese subjects with OSAS. Thirty-one patients with OSAS, diagnosed through polysomnography at the Pulmonology Outpatient Clinic of the Otávio de Freitas-HOF Hospital, were selected. These individuals were instructed to respond to two self-administered questionnaires, the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESE). Later, they underwent pulmonary function testing through spirometry and inspiratory muscle strength from the manovacuometry. For the evaluation of functional capacity, the subjects were submitted to two walking tests; The shuttle test and the six-minute walk test. The Kolmogorov-Smirnov test was performed to evaluate the normality of the sample. The Spearman test was used for correlation and for differences between means the Student t test for independent samples. The results showed that the sample had forced vital capacity (FVC) (predicted%) of 76.4 ± 12.3% and forced expiratory volume first second (FEV1) (predicted%) of 80.1 ± 6.3 %. The maximal inspiratory pressure (MIP) was 60.0 ± 21.9 cmH2O and the maximum expiratory pressure (MEP) was 81.3 ± 22.2 cmH2O. The distances covered in the test shuttle and the six-minute walk test were 221 ± 97m and 480 ± 67.3m, respectively. There was a moderate and positive correlation between the distance traveled in the shuttle test and the FVC (r = 0.658 and p = 0.001) and between the test shuttle distance and FEV1 (r = 0.522, p = 0.003). According to the results of the sample, in obese individuals with untreated OSAS there is a reduction in lung function, inspiratory muscle strength and physical capacity. In addition, it has been observed that the decline of lung function, but not respiratory muscle strength, is associated with physical effort tolerance in these patients.