Spirometric values of obese and non-obese subjects on orthostatic, sitting and supine positions

Abstract

BACKGROUND: It is possible that obesity could lead to pulmonary restriction with decreasing lung volumes. However, controversies about this restriction and its etiology still exist. Thus, the purpose of this report was to evaluate the effects of body weigh excess on spirometry, on three different body positions, evaluated by Body Mass Index (BMI), percentage of fatness and the ratio of abdominal girth to hip breadth (AG/HB). METHODS: Forty-six sedentary volunteers, with ages between 20 and 40 years, were studied and distributed on five groups, based on BMI. Skin fold thickness and ratio of abdominal girth to hip breadth (AG/HB) of the volunteers were measured. FVC, FEV1 and ratio of FEV1 to FVC were measured on three different body positions--sitting, supine and orthostatic positions. RESULTS: Comparing the values measured and predicted between the groups, no difference was detected. Comparing body positions, the supine position shows lower values than sitting and orthostatic positions (p<0.05). Associations between CVF, VEF1 e VEF1/CVF values and BMI, percentage of fatness and ratio of AG/HB were not found. CONCLUSIONS: Spirometric values from obese people are into normality range and decrease on the supine position.