Does physical activity affect respiratory muscle strength?

Abstract

Introduction: Few studies relate respiratory muscle strength to physical activity in healthy children. One study reports that boys aged 7-8y who swim have larger maximum respiratory pressures than those who are sedentary or play indoor soccer (Santos et al Physiother Theory Pract 2012:28:26-31). Data in healthy children, including girls, over a wider age range are lacking. Aims: To compare maximum inspiratory and expiratory pressures (MIP and MEP) in healthy children according to (i) whether they engage in exercise or not, and (ii) whether they spend >6h per day in sedentary occupations outside school. Method: We measured spirometry, MIP and MEP (Vyntus pneumo, Carefusion), and height and weight in children aged 5-11 in their primary schools. A questionnaire determined which children engaged in exercise (defined as spending more than 10 minutes at a time in vigorous physical activity), and whether they spent more than six hours per day in sedentary activity. Results: We studied 51children; 13 reported no exercise. Twenty-seven children spent >6hr per day in sedentary activities. We obtained MIP on 44 and MEP on 47 children. There was no significant relationship between respiratory muscle strength and height. There was an overall trend for higher respiratory pressures in the more physically active children. Conclusion: MIP and MEP show considerable variability in healthy children. Preliminary data suggest that physical activity in children may influence respiratory muscle strength, but a bigger sample size is required.