Association between body composition and maximal respiratory pressures in women aged 40-80 years old

Abstract

Background: Some authors say the excess of body mass and fat distribution in the thorax upper region do not promote respiratory muscle dysfunction. Some others report the excess of adipose tissue in the thoracic cavity and abdomen causes mechanical disadvantage to respiratory muscles. Aim: This study investigated associations between body composition and maximal respiratory pressures (MRP) in women. Methods: 204 women (40-80 years old) were classified as normal weight, overweight, obese grade I, II and III, according to their body mass index (BMI), and evaluated in relation to body composition (body fat mass and fat free mass) with a bioelectrical impedance analysis (BIA) device. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were assessed with a digital manometer. We performed multiple linear regression analyses to model the effect of BMI and the variables of body composition on MIP and MEP, adjusting for covariates (age, income and education). Results: In the fully adjusted models, women classified as normal and overweight performed significantly weaker MIP (-42.8 cmH2O, p Conclusion: In the studied population, we observed higher MRP for higher BMI categories. Since we found MRP significantly associated only to fat free mass and not to body fat mass, we hypothesized that the women considered obese develop more muscle mass, with significant changes in MRP.