Effects of F1O2 on leg VO2 during cycle ergometry in sedentary subjects
Effects of F1O2 on leg VO2 during cycle ergometry in sedentary subjects
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DOI：
10.1097/00005768-199805000-00009
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发表时间：
1998-05-01
期刊：
影响因子：
--
通讯作者：
Wagner, PD
中科院分区：
文献类型：
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作者：
Cardús, J;Marrades, RM;Wagner, PD
在最近一项对完全久坐的正常年轻受试者的研究中，当F1 O2从0.15降低到0.12时，腿部VO 2 max因缺氧而与平均毛细血管PO 2成比例地降低。然而.最大摄氧量从F1 O2 = 0.15增加到0.21，低于平均毛细血管PO 2增加的预期值。这一发现使我们假设，在久坐不动的受试者呼吸室内空气，VO 2 max是不受限制的O-2供应，而是由线粒体的氧化能力。本研究试图通过评估腿部VO 2 max（VO（2）leg）呼吸100% O-2以及常氧和缺氧情况，在久坐受试者中获得支持或反对这一假设的进一步证据。分析了在F1 O2 = 0.12、0.15和0.21下研究的18例受试者的数据以及在0.12、0.15和1.00下研究的6例受试者的数据。在所有24例患者中，我们通过动脉和静脉采血以及在每个F1 O2时进行最大踏车测力时的热稀释腿部血流量来测量下肢VO（2）。相对于在F1 O2 = 0.15时观察到的情况，室内空气或100%O-2呼吸并没有增加下肢VO（2），但当呼吸12%O-2时，下肢VO（2）减少。在F_1O_2 = 0.12和0.15时的数据与先前的最大VO_2max的O-_2供应限制的预测一致。这些结果证实并扩展了我们先前的观察结果，即在久坐不动的情况下，与训练有素的受试者相反，肌肉VO 2 max仅在缺氧时受到O-2供应的限制。
In a recent study of completely sedentary normal young subjects, leg VO2max was reduced by hypoxia in proportion to mean capillary PO2 as F1O2 was reduced from 0.15 to 0.12. However. the increase in VO2max from F1O2 = 0.15 to 0.21 was less than expected for the increase in mean capillary PO2. This finding has led us to hypothesize that in sedentary subjects breathing room air, VO2max is not limited by O-2 supply but rather by oxidative capacity of mitochondria. The present study sought to obtain further evidence for or against this hypothesis in sedentary subjects by assessing leg VO2max (VO(2)leg) breathing 100% O-2, as well as in normoxia and hypoxia. Data from 18 subjects studied at F1O2 = 0.12, 0.15, and 0.21 and from six more studied at 0.12, 0.15, and 1.00 were analyzed. In all 24 we measured VO(2)leg by arterial and venous blood sampling and thermodilution leg blood flow during maximal cycle ergometry at each F1O2. VO(2)leg was not increased by room air or 100% O-2 breathing relative to that observed at F1O2 = 0.15, but it was reduced while breathing 12% O-2. The data at F1O2 = 0.12 and 0.15 conformed to the predictions of O-2 supply Limitation of maximal VO2max as previously. These results confirm and extend our prior observations that in sedentary, as opposed to trained subjects,muscle VO2max is O-2 supply limited only in hypoxia.