Some Aspects of Pulmonary Functions in the Underweight and Overweight Human Subjects

Several factors such as respiratory muscle strength, lung compliance, resistance to airflow etc., affect the lung functions. Studies on pulmonary functions in relation to body composition are lacking. We hypothesized that lung functions both in the obese and the undernourished subjects would be reduced due to mechanical disadvantages. Therefore, the present study was designed with the aim to compare some aspects of lung functions in humans with varying body fat content and fat free mass. A large number of young college students of both sexes included in the study were classified into normal (N), undernourished (UN) and overweight (OW) groups based on their body mass index (BMI). Body fat (BF) and lean body mass (LBM) were estimated in each subject using Futrex -5000 A. The body fat varied from 13% to 25% in male subjects and 26% to 35% in females as BMI increased. Male subjects with low BMI had 87% LBM while those with normal and high BMI had 80% and 75% respectively. Correspondingly, females had lower LBM values of 73%, 69% and 65% as the BMI increased. Interestingly, absolute values of LBM content increased in subjects of both sexes with increments in BMI. Pulmonary functions including , forced vital capacity (FVC), forced expiratory volume in the first one second (FEV1) and peak expiratory flow rate (PEFR) were also assessed by using Morgan’s spirocheck. Data was analysed using ANOVA and unpaired t test for statistical significance of differences. The relationship between lung functions, BMI, BF and LBM was not significantly different from one another either in the male or female groups except for differences between the genders. FVC was about 3.7 L, FEV1% was about 80% and PEFR was about 375 L/min in male subjects while the females recorded significantly lower values.