Pulmonary ventilation ratios in normal and overweight/obese children carrying variously loaded backpacks

Abstract

Objectives: Pulmonary response to physical activity (PA) varies with intensity, Body Mass Index (BMI). The study records Inspiratory: expiratory ratio [I:E ratio] reflecting oxygenation status and breath counts during progression of PA which is undocumented, specifically, during schoolbag carriage- the most common PA in children. Design: 60 walk sessions (N=60), 20-min each, were recorded in 12 male schoolchildren (10-15 years) (n=6 normal BMI, n=6 overweight/obese BMI). They walked at their preferred pace with schoolbags weighing 0, 4, 8, 12 and 16% of bodyweight on 5 different occassions. Methods: The bodyweight and height was recorded for participants on obtaining guardian’s consent. Pulmonary response during walk was recorded using COSMED k4b2 which records data for each breath taken during the 20-min walk. Results: Breath counts increased with load, duration of schoolbag carriage and BMI. Ti and Te differed significantly (p<0.01) with load, duration of schoolbag carriage and BMI. Percentage of breaths deviating from normal I:E ratio of 1:2 were higher in case of higher loads and BMI. Conclusion: Equal and inverse ratio ventilations increased during the end of PA and may be the normal physiological response to improve oxygenation in body.