کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2847973 | 1167398 | 2008 | 7 صفحه PDF | دانلود رایگان |
How children are able to adapt their ventilation to the intensity of exercise faster than adults remain unclear. We hypothesized that differences of V˙E observed between children and adults depend on either peripheral chemoreceptors or central command activity. We examined ventilatory control parameters in either normoxic or hypoxic condition (FIO2=0.15FIO2=0.15). We analyzed the adaptability of the respiratory exchanges by (i) the measurement of ventilatory kinetics time-constant and (ii) the central command by the mouth-occlusion pressure (P0.1). A group of nine pre-pubescent children (mean age 9.5 ± 1 years) and a group of eight adults (mean age 24 ± 3.1 years) performed a constant-load exercise. In normoxia, children had significantly shorter time-constant (τ ) V˙CO2 (respectively, 38.5 ± 4.3 and 53.1 ± 5.3 s; P < 0.001), τ V˙E (respectively, 52.5 ± 13.1 s vs. 66.1 ± 12.3 s; P < 0.001), and τP0.1 (57.4 ± 15.4 and 61.0 ± 12.9 s, respectively; P < 0.001) than adults. In hypoxia, children exhibited shorter τP0.1/VT/Ti compare to adults. Reinforced by the significant correlation between τ V˙E and τP0.1/VT/Ti for children but not adults, we concluded that ventilatory response differences could be due in part to the respiratory system impedance.
Journal: Respiratory Physiology & Neurobiology - Volume 161, Issue 3, 31 May 2008, Pages 239–245