Influence of gender on ventilatory efficiency during exercise in young children

Abstract

In this study, we assessed the ventilatory response in 84 children (46 males: age 8.1 ± 1.0 years, body mass 34.2 ± 7.9 kg, height 1.32 ± 0.16 m; 38 females: age 8.0 ± 0.8 years, body mass 31.7 ± 8.7 kg, height 1.31 ± 0.08 m) during a cycle ergometer test to determine if there was an influence of gender on ventilatory efficiency. The test commenced at 25 W and increased by 10 W every minute. Expired air was collected through a face mask and analysed breath by breath. The ventilatory anaerobic threshold was determined according to gas exchange methods and we focused our attention on the analysis of carbon dioxide production ([Vdot]CO₂), ventilation ([Vdot] _E), the ratio [Vdot] _E/[Vdot]CO₂ and its slope. Differences between the sexes at maximal power output were strongly significant for [Vdot] _E and [Vdot]CO₂ (P = 0.0001 and P = 0.0004 respectively) and moderately significant for the [Vdot] _E/[Vdot]CO₂ ratio (P = 0.05). The slope of [Vdot] _E versus [Vdot]CO₂ was 30.8 ± 4.2 for males and 29.4 ± 3.2 for females, with no difference between the sexes (P = 0.1). In conclusion, although the peak values of [Vdot] _E and [Vdot]CO₂ were significantly different between the sexes, there were no such differences in ventilatory efficiency during a maximal incremental test expressed as the slope of [Vdot] _E/[Vdot]CO₂, at least in young children.

Keywords:

• Ventilatory efficiency
• gender
• children
• ventilation and exercise