Abstract
BACKGROUND: Food intake augments CO(2) production; however, minute ventilation is not augmented during exercise after food intake. Respiratory chemoreceptors respond to CO(2) and influence respiration. We examined the effect of food intake on respiratory chemosensitivity to CO(2) in young adults. METHODS: The hypercapnic ventilatory response was measured in eleven healthy individuals before and after food intake. To evaluate the respiratory chemoreflex response to CO(2), minute ventilation was plotted against end-tidal PCO(2) using data obtained with the rebreathing method. RESULTS: Sublingual temperature, CO(2) output, minute ventilation, and end-tidal PCO(2) were all significantly higher at baseline in the session after food intake than in the session before food intake. On the other hand, there was no significant difference in chemosensitivity to CO(2) between the sessions before and after food intake (1.60 ± 0.62 vs. 1.53 ± 0.62 l min(-1) mmHg(-1)). CONCLUSIONS: Food intake does not influence respiratory chemosensitivity to CO(2) in young adults, which is different from infants. This suggests that control of respiration differs between young adults and infants and that the elevated minute ventilation after food intake in young adults is not caused by a change in respiratory chemosensitivity.