Relating pulmonary oxygen uptake to muscle oxygen consumption at exercise onset: in vivo and in silico studies
Relating pulmonary oxygen uptake to muscle oxygen consumption at exercise onset: in vivo and in silico studies
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DOI：
10.1007/s00421-006-0176-y
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发表时间：
2006-07-01
影响因子：
3
通讯作者：
Cabrera, M. E.
中科院分区：
文献类型：
--
作者：
Lai, N.;Dash, R. K.;Cabrera, M. E.
在涉及大肌肉块的运动过程中，评估体内肌肉耗氧量 UO2m 对于研究运动开始时调节能量代谢的机制至关重要。虽然在这些情况下 UO2m 在技术上很难获得，但肺摄氧量 VO2p 可以轻松测量并用作 UO2m 的替代值。然而，在人类运动的非稳定阶段，VO2p 和 UO2m 之间的定量关系需要建立。应用基于血液和组织细胞动态质量平衡的氧气运输和利用计算模型来量化模型模拟的 UO2m 和测量的 VO2p 在中等 (M)、重度 (H) 和极重 (V) 强度运动期间的动态关系。分别使用间接量热法和近红外光谱 (NIRS) 测量 7 名人类受试者的 VO2p 和肌肉氧饱和度 StO(2m)。 VO2p 和 StO(2m) 在每个强度下的动态响应与之前发布的数据一致。肌肉耗氧量的响应时间，tau(UO2m)；通过模型结果和 StO(2m) 测量结果的直接比较估计，StO(2m) 明显快于肺摄氧量 tau(VO2p)（P < 0.001）； （M：13 +/- 4 与 65 +/- 7 秒；H：13 +/- 4 与 100 +/- 24 秒；V：15 +/- 5 与 82 +/- 31 秒）。因此，通过考虑血液和组织中氧储存的动态并通过肌肉氧合测量确定肌肉耗氧量，本研究证明了运动开始时 UO2m 和 VO2p 之间存在显着的时间分离。
Assessment of the rate of muscle oxygen consumption, UO2m, in vivo during exercise involving a large muscle mass is critical for investigating mechanisms regulating energy metabolism at exercise onset. While UO2m is technically difficult to obtain under these circumstances, pulmonary oxygen uptake, VO2p, can be readily measured and used as a proxy to UO2m. However, the quantitative relationship between VO2p and UO2m during the nonsteady phase of exercise in humans, needs to be established. A computational model of oxygen transport and utilization-based on dynamic mass balances in blood and tissue cells-was applied to quantify the dynamic relationship between model-simulated UO2m and measured VO2p during moderate (M), heavy (H), and very heavy (V) intensity exercise. In seven human subjects, VO2p and muscle oxygen saturation, StO(2m), were measured with indirect calorimetry and near infrared spectroscopy (NIRS), respectively. The dynamic responses of VO2p and StO(2m) at each intensity were in agreement with previously published data. The response time of muscle oxygen consumption, tau(UO2m); estimated by direct comparison between model results and measurements of StO(2m) was significantly faster (P < 0.001) than that of pulmonary oxygen uptake, tau(VO2p); (M: 13 +/- 4 vs. 65 +/- 7 s; H: 13 +/- 4 vs. 100 +/- 24 s; V: 15 +/- 5 vs. 82 +/- 31 s). Thus, by taking into account the dynamicsThus, by taking into account the dynamics of oxygen stores in blood and tissue and determining muscle oxygen consumption from muscle oxygenation measurements, this study demonstrates a significant temporal dissociation between UO2m and VO2p at exercise onset.