Canadian Centre for Activity and Aging, The University of Western Ontario, London, ON, Canada.
Eur J Appl Physiol. 2011 Dec;111(12):3107-18. doi: 10.1007/s00421-011-1937-9. Epub 2011 Apr 3.
The relationship between the adjustment of muscle deoxygenation (∆[HHb]) and phase II VO(2p) was examined in subjects presenting with a range of slow to fast VO(2p) kinetics. Moderate intensity VO(2p) and ∆[HHb] kinetics were examined in 37 young males (24 ± 4 years). VO(2p) was measured breath-by-breath. Changes in ∆[HHb] of the vastus lateralis muscle were measured by near-infrared spectroscopy. VO(2p) and ∆[HHb] response profiles were fit using a mono-exponential model, and scaled to a relative % of the response (0-100%). The ∆[HHb]/∆VO(2p) ratio for each individual (reflecting the matching of O(2) distribution to O(2) utilization) was calculated as the average ∆[HHb]/∆VO(2p) response from 20 to 120 s during the exercise on-transient. Subjects were grouped based on individual phase II VO(2p) time-constant (τVO(2p)): <21 s [very fast (VF)]; 21-30 s [fast (F)]; 31-40 s [moderate (M)]; >41 s [slow (S)]. The corresponding ∆[HHb]/∆VO(2p) were 0.98 (VF), 1.05 (F), 1.09 (M), and 1.22 (S). The larger ∆[HHb]/∆VO(2p) in the groups with slower VO(2p) kinetics resulted in the ∆[HHb]/∆VO(2p) displaying a transient "overshoot" relative to the subsequent steady state level, which was progressively reduced as τVO(2) became smaller (r = 0.91). When τVO(2p) > ~20 s, the rate of adjustment of phase II VO(2p) appears to be mainly constrained by the matching of local O(2) distribution to muscle VO(2). These data suggest that in subjects with "slower" VO(2) kinetics, the rate of adjustment of VO(2) may be constrained by O(2) availability within the active tissues related to the matching of microvascular O(2) distribution to muscle O(2) utilization.
在呈现出一系列慢至快的 VO₂p 动力学的受试者中，研究了肌肉去氧（∆[HHb]）调节与相 II VO₂p 之间的关系。在 37 名年轻男性（24 ± 4 岁）中检查了中等强度的 VO₂p 和 ∆[HHb]动力学。通过逐口气测量 VO₂p。通过近红外光谱测量股外侧肌的 ∆[HHb]变化。使用单指数模型拟合 VO₂p 和 ∆[HHb]响应曲线，并将其归一化为响应的相对百分比（0-100%）。对于每个个体，∆[HHb]/∆VO₂p 比值（反映了 O₂ 分布与 O₂ 利用的匹配）被计算为运动过程中 20 到 120 秒之间的平均∆[HHb]/∆VO₂p 响应，在运动瞬变过程中。根据个体相 II VO₂p 时间常数（τVO₂p）对受试者进行分组：<21 s[非常快（VF）]；21-30 s[快（F）]；31-40 s[中等（M）]；>41 s[慢（S）]。相应的 ∆[HHb]/∆VO₂p 分别为 0.98（VF）、1.05（F）、1.09（M）和 1.22（S）。VO₂p 动力学较慢的组中较大的 ∆[HHb]/∆VO₂p 导致 ∆[HHb]/∆VO₂p 相对于随后的稳态水平表现出短暂的“过冲”，随着 τVO₂p 变小，这种过冲逐渐减小（r = 0.91）。当 τVO₂p >~20 s 时，相 II VO₂p 的调整速率似乎主要受到与肌肉 VO₂ 利用相匹配的局部 O₂ 分布的限制。这些数据表明，在 VO₂ 动力学较慢的受试者中，VO₂ 的调整速率可能受到与微血管 O₂ 分布与肌肉 O₂ 利用相匹配有关的活性组织中 O₂ 可用性的限制。
