Ward Alexandra M M, Guluzade Nasimi A, Kowalchuk John M, Keir Daniel A
School of Kinesiology, The University of Western Ontario, 1151 Richmond Street, London, ON, N6A 3K7, Canada.
Department of Physiology and Pharmacology, The University of Western Ontario, London, ON, Canada.
Eur J Appl Physiol. 2023 Mar;123(3):509-522. doi: 10.1007/s00421-022-05073-4. Epub 2022 Nov 12.
During a step-change in exercise power output (PO), ventilation () increases with a similar time course to the rate of carbon dioxide delivery to the lungs (. To test the strength of this coupling, we compared and kinetics from ten independent exercise transitions performed within the moderate-intensity domain. Thirteen males completed 3-5 repetitions of ∆40 W step transitions initiated from 20, 40, 60, 80, 100, and 120 W on a cycle ergometer. Preceding the ∆40 W step transitions from 60, 80, 100, and 120 W was a 6 min bout of 20 W cycling from which the transitions of variable ∆PO were examined. Gas exchange ( and oxygen uptake, ) and were measured by mass spectrometry and volume turbine. The kinetics of the responses were characterized by the time constant (τ) and amplitude (Δ/Δ). Overall, kinetics were consistently slower than kinetics (by ~ 45%) and τ rose progressively with increasing baseline PO and with heightened ∆PO from a common baseline. Compared to τ, τ was on average slightly greater (by ~ 4 s). Repeated-measures analysis of variance revealed that there was no interaction between τ and τ in either the variable baseline (p = 0.49) and constant baseline (p = 0.56) conditions indicating that each changed in unison. Additionally, for Δ/Δ, there was no effect of either variable baseline PO (p = 0.05) or increasing ΔPO (p = 0.16). These data provide further evidence that, within the moderate-intensity domain, both the temporal- and amplitude-based characteristics of V̇ kinetics are inextricably linked to those of .
在运动功率输出（PO）发生阶跃变化期间，通气量（）的增加与二氧化碳输送到肺部的速率具有相似的时间进程（。为了测试这种耦合的强度，我们比较了在中等强度范围内进行的10次独立运动转换过程中的和动力学。13名男性在功率自行车上完成了从20、40、60、80、100和120W开始的3 - 5次40W阶跃转换。在从60、80、100和120W进行40W阶跃转换之前，先进行6分钟的20W骑行，然后检查可变∆PO的转换。通过质谱仪和容积式涡轮机测量气体交换（和摄氧量，）以及。反应动力学通过时间常数（τ）和幅度（∆/∆）来表征。总体而言，动力学始终比动力学慢（约45%），并且τ随着基线PO的增加以及从共同基线升高的∆PO而逐渐上升。与τ相比，τ平均略大（约4秒）。重复测量方差分析表明，在可变基线（p = 0.49）和恒定基线（p = 0.56）条件下，τ和τ之间均无相互作用，表明二者同步变化。此外，对于∆/∆，可变基线PO（p = 0.05）或增加的∆PO（p = 0.16）均无影响。这些数据进一步证明，在中等强度范围内，动力学基于时间和幅度的特征都与的特征紧密相连。
