EFFECT OF CHANGE IN P-50 ON EXERCISE TOLERANCE AT HIGH-ALTITUDE - A THEORETICAL-STUDY
EFFECT OF CHANGE IN P-50 ON EXERCISE TOLERANCE AT HIGH-ALTITUDE - A THEORETICAL-STUDY
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DOI：
10.1152/jappl.1982.53.6.1487
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发表时间：
1982-01-01
影响因子：
3.3
通讯作者：
WEST, JB
中科院分区：
文献类型：
--
作者：
BENCOWITZ, HZ;WAGNER, PD;WEST, JB
对海拔高度的习服常常导致O2解离曲线（ODC）的显著移动。据报道，左移ODC可增加中等海拔人类的运动耐量，并增加呼吸低氧气体混合物的大鼠的存活率。这一悖论是用肺气体交换的计算机模型来检验的。波尔积分程序允许肺泡毛细血管扩散。当扩散平衡完成时，混合静脉（P.hivin.vO2）和动脉PO2 [分压]随着O2消耗（. ovrhdot.VO2）的增加而下降，但P.hivin.vO2接近平台。在这些条件下，右移ODC是有利的（较高的P.hivin.vO2），但在所有非常高的海拔。如果VO2或VO2充分增加，则O2转移的扩散限制可在任何海拔发生。如果发生这种情况，左移的ODC导致更高的计算VO2 max（与标准ODC相比）。扩散限制总是在右移ODC比左移ODC更低的VO2处发生。在一定海拔高度上，ODC的负移或负移是否有利于气体交换取决于是否存在扩散限制。
Acclimatization to altitude often results in a rightward shift of the O2 dissociation curve (ODC). A left-shifted ODC is reported to increase exercise tolerance in humans at medium altitude and increase survival in rats breathing hypoxic gas mixtures. This paradox was examined using a computer model of pulmonary gas exchange. A Bohr integration procedure allowed for alveolar-capillary diffusion. When diffusion equilibration was complete, mixed venous (P.hivin.vO2) and arterial PO2 [partial pressure] fell as O2 consumption (.ovrhdot.VO2) was increased, but P.hivin.vO2 approached a plateau. Under these conditions a right-shifted ODC is advantageous (higher P.hivin.vO2) at all but very high altitudes. Diffusion limitation of O2 transfer may occur at any altitude if .ovrhdot.VO2 is increased sufficiently. If this occurs, a left-shifted ODC results in higher calculated .ovrhdot.VO2 max (compared with the standard ODC). Diffusion limitation always occurs at a lower .ovrhdot.VO2 with a right-shifted ODC than with a left-shifted ODC. Whether a leftward or rightward shift in the ODC is advantageous to gas exchange at an altitude depends on the presence or absence of diffusion limitation.