We analysed the importance of systemic and peripheral arteriovenous O₂ difference ( difference and a‐v_fO₂ difference, respectively) and O₂ extraction fraction for maximal oxygen uptake ( ). Fick law of diffusion and the Piiper and Scheid model were applied to investigate whether diffusion versus perfusion limitations vary with . Articles (n = 17) publishing individual data (n = 154) on , maximal cardiac output ( ; indicator‐dilution or the Fick method), difference (catheters or the Fick equation) and systemic O₂ extraction fraction were identified. For the peripheral responses, group‐mean data (articles: n = 27; subjects: n = 234) on leg blood flow (LBF; thermodilution), a‐v_fO₂ difference and O₂ extraction fraction (arterial and femoral venous catheters) were obtained. and two‐LBF increased linearly by 4.9‐6.0 L · min^–1 per 1 L · min^–1 increase in (R² = .73 and R² = .67, respectively; both P < .001). The difference increased from 118‐168 mL · L^–1 from a of 2‐4.5 L · min^–1 followed by a reduction (second‐order polynomial: R² = .27). After accounting for a hypoxemia‐induced decrease in arterial O₂ content with increasing (R² = .17; P < .001), systemic O₂ extraction fraction increased up to ~90% ( : 4.5 L · min^–1) with no further change (exponential decay model: R² = .42). Likewise, leg O₂ extraction fraction increased with to approach a maximal value of ~90‐95% (R² = .83). Muscle O₂ diffusing capacity and the equilibration index Y increased linearly with (R² = .77 and R² = .31, respectively; both P < .01), reflecting decreasing O₂ diffusional limitations and accentuating O₂ delivery limitations. In conclusion, although O₂ delivery is the main limiting factor to , enhanced O₂ extraction fraction (≥90%) contributes to the remarkably high in endurance‐trained individuals.

中文翻译：

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氧提取分数对健康年轻男性最大摄氧量的贡献。

我们分析了全身和外周动静脉 O ₂差异（分别为差异和 a-v _f O ₂差异）和 O ₂提取分数对最大摄氧量的重要性（）。应用 Fick 扩散定律和 Piper 和 Scheid 模型来研究扩散与灌注限制是否随。 发表 关于最大心输出量（指标稀释或 Fick 方法）、差异（导管或 Fick 方程）和全身 O _{2 的}个体数据 ( n = 154) 的文章 ( n = 17)提取部分进行了鉴定。对于外周反应， 关于腿部血流量（LBF；热稀释）、a-v _f O ₂差异和 O ₂提取分数（动脉和股静脉导管）的组平均数据（文章：n  = 27；受试者：n = 234）) 获得。和双 LBF 线性增加 4.9-6.0 L · min ^–1每增加1 L · min ^–1（分别为R ²  = .73 和R ²  = .67；两者P  < .001）。该差从118-168毫升增加·大号^–1来自2-4.5 L · min ^–1的 a，然后是减少（二阶多项式：R ²  = .27）。考虑到低氧血症引起的动脉 O ₂含量随着增加（R ²  = .17；P  < .001）而降低后，全身 O ₂提取分数增加到~90%（：4.5 L · min ^–1）而没有进一步变化（指数衰减模型：R ²  = .42）。同样，腿 O ₂提取分数增加，接近 ~90-95% 的最大值 ( R ² = .83）。肌肉 O ₂扩散能力和平衡指数Y 分别随( R ²  = .77 和R ²  = .31；两者P  < .01)线性增加，反映了 O ₂扩散限制的减少和 O ₂输送限制的加剧。总之，虽然 O ₂输送是 的主要限制因素，但增强的 O ₂提取率（≥90%）有助于耐力训练个体的显着升高。