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首页> 外文期刊>Canadian Journal of Physiology and Pharmacology >Effect of hyperoxia and hypoxia on leg blood flow and pulmonary and leg oxygen uptake at the onset of kicking exercise.
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Effect of hyperoxia and hypoxia on leg blood flow and pulmonary and leg oxygen uptake at the onset of kicking exercise.

机译：高氧和缺氧对踢腿运动开始时腿部血流以及肺部和腿部氧气摄取的影响。

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The purpose of this study was to examine the interactions of adaptations in O2 transport and utilization under conditions of altered arterial O2 content (CaO2), during rest to exercise transitions. Simultaneous measures of alveolar (VO2alv) and leg (VO2mus) oxygen uptake and leg blood flow (LBF) responses were obtained in normoxic (FiO2 (inspired fraction of O2) = 0.21), hypoxic (FiO2 = 0.14), and hyperoxic (FiO2 = 0.70) gas breathing conditions. Six healthy subjects performed transitions in leg kicking exercise from rest to 48 +/- 3 W. LBF was measured continuously with pulsed and echo Doppler ultrasound methods, VO2alv was measured breath-by-breath at the mouth and VO2mus was determined from LBF and radial artery and femoral vein blood samples. Even though hypoxia reduced CaO2 to 175.9 +/- 5.0 from 193.2 +/- 5.0 mL/L in normoxia, and hyperoxia increased CaO2 to 205.5 +/- 4.1 mL/L, there were no differences in the absolute values of VO2alv or VO2mus across gas conditions at any of the rest or exercise time points. A reduction in leg O2 delivery in hypoxia at the onset of exercise was compensated by a nonsignificant increase in O2 extraction and later by small increases in LBF to maintain VO2mus. The dynamic response of VO2alv was slower in the hypoxic condition; however, hyperoxia did not affect the responses of oxygen delivery or uptake at the onset of moderate intensity leg kicking exercise. The finding of similar VO2mus responses at the onset of exercise for all gas conditions demonstrated that physiological adaptations in LBF and O2 extraction were possible, to counter significant alterations in CaO2. These results show the importance of the interplay between O2 supply and O2 utilization mechanisms in meeting the challenge provided by small alterations in O2 content at the onset of this submaximal exercise task.
机译：这项研究的目的是研究在从静止到运动的过渡过程中，在动脉血中氧含量（CaO2）改变的条件下，氧在运输和利用中的适应性相互作用。同时测量了高氧（FiO2（O2的吸入分数）= 0.21），低氧（FiO2 = 0.14）和高氧（FiO2 = 0.70）气体呼吸条件。六名健康受试者的腿部踢腿运动从休息到48 +/- 3 W进行了过渡。使用脉冲和回波多普勒超声方法连续测量LBF，通过口呼吸来测量VO2alv，并通过LBF和放射状确定VO2mus动脉和股静脉的血液样本。即使缺氧使常氧状态下的CaO2从193.2 +/- 5.0 mL / L降低至175.9 +/- 5.0，高氧血症使CaO2升高至205.5 +/- 4.1 mL / L，但整个过程中VO2alv或VO2mus的绝对值没有差异在任何休息或运动时间点的气体状况。运动开始时在低氧状态下腿部O2输送量的减少可以通过O2提取量的无明显增加来补偿，随后通过LBF的少量增加来保持VO2mus来弥补。缺氧条件下VO2alv的动态反应较慢;然而，在中度强度的腿踢运动开始时，高氧并不影响氧气输送或摄取的反应。在所有气体条件下，运动开始时都发现相似的VO2mus反应，这表明在LBF和O2提取中进行生理适应是可能的，以应对CaO2的显着变化。这些结果表明，在这种次最大运动任务开始时，氧气供应和氧气利用机制之间的相互作用对于迎接氧气含量的微小变化所带来的挑战非常重要。

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