Ventilatory responses to hypoxia in healthy subjects: a comparison between young children and adults

Ventilatory responses and breathing patterns during acute hypoxia have been studied at sea level in healthy subjects (8 children, 8 adults). While breathing ambient air it appears that, compared to adults, children hyperventilate when ventilation is standardized to body mass unit. During hypoxia, ventilatory strategy differs with age: when adults essentially increase tidal volume (VT), children increase VT and ventilatory frequency (fr). The ventilatory steady-state response to hypoxia is lesser in children than in adults, that is to say, children have a lower O2 ventilatory sensitivity. These results, which show that adults and children have qualitatively and quantitatively different ventilatory responses to hypoxia, are interpreted in terms of the ability to displace gaseous volumes.