Wagner P D, Roca J, Hogan M C, Poole D C, Bebout D C, Haab P
Department of Medicine, University of California San Diego, La Jolla 92093.
Adv Exp Med Biol. 1990;277:825-33. doi: 10.1007/978-1-4684-8181-5_94.
The four experiments summarized above demonstrate that there is a strong relationship between both measured muscle venous PO2 and calculated mean muscle capillary PO2 and VO2max. This is true for whole body or exercising muscle VO2max, and is seen both in isolated canine gastrocnemius and intact man. This behavior is exactly what would be expected if the diffusing properties for oxygen in skeletal muscle play a constraining role in setting maximum VO2. These data therefore support the hypothesis we advanced (Wagner, 1988a; Wagner, 1988b), that it is a quantitative integrative relationship between convective and diffusive phenomena that combine to set maximum VO2. A specific prediction of this integrative hypothesis (i.e., the non-uniqueness of VO2max as a function of convective oxygen delivery) was confirmed (Experiment 3). While at this point in time phenomena such as perfusion heterogeneity and muscle shunts cannot be quantitatively taken into account in such analyses, the remarkable concurrence between expectations of the hypothesis and experimental data continue to lend support to the basic idea that maximum VO2 is not limited by any single step of the oxygen transport pathway from atmosphere to mitochondria, but rather by the way in which each and every step combines with every other step to determine oxygen supply.
上述四个实验表明，所测肌肉静脉血氧分压和计算得出的平均肌肉毛细血管血氧分压与最大摄氧量之间均存在密切关系。这对于全身或运动肌肉的最大摄氧量均适用，在离体犬腓肠肌和完整人体中均可见到。如果骨骼肌中氧气的扩散特性在设定最大摄氧量方面起限制作用，那么这种表现正是所预期的。因此，这些数据支持了我们提出的假说（瓦格纳，1988a；瓦格纳，1988b），即对流和扩散现象之间的定量综合关系共同决定了最大摄氧量。这一综合假说的一个具体预测（即最大摄氧量作为对流性氧气输送的函数并非唯一）得到了证实（实验3）。虽然目前在这类分析中还无法定量考虑诸如灌注不均一性和肌肉分流等现象，但假说预期与实验数据之间的显著一致性继续支持这样一个基本观点，即最大摄氧量并非受从大气到线粒体的氧气运输途径中任何单个步骤的限制，而是受每个步骤与其他每个步骤相互结合以确定氧气供应的方式的限制。
