Objective: To investigate whether ventilatory factors limit exercise in overweight and obese children during a 6-min step test and to compare ventilatory responses during this test with those of healthy weight children.
Design: Cross-sectional, prospective comparative study.
Subjects: Twenty-six overweight/obese subjects and 25 healthy weight subjects with no known respiratory illness.
Measurements: Various fatness and fat distribution parameters (using air displacement plethysmography and anthropometry), pulmonary function tests, breath-by-breath gas analysis during exercise, perceived exertion.
Results: Young people who are overweight or obese are more likely to experience expiratory flow limitation (expFL) during submaximal exercise compared with their healthy weight peers [OR 7.2 (1.4, 37.3), P=0.019]. Subjects who had lower lung volumes at rest were even more likely to experience exercise-induced expFLs [OR 8.35 (1.4-49.3)]. Both groups displayed similar breathing strategies during submaximal exercise.
Conclusion: Young people who are overweight/obese are more likely to display expFL during submaximal exercise compared with children of healthy weight . Use of compensatory breathing strategies appeared to enable overweight children to avoid the experience of breathlessness at this intensity of exercise.