Bender P R, McCullough R E, McCullough R G, Huang S Y, Wagner P D, Cymerman A, Hamilton A J, Reeves J T
Cardiovascular Pulmonary Research Laboratory, University of Colorado Health Sciences Center, Denver 80262.
J Appl Physiol (1985). 1989 Jun;66(6):2733-8. doi: 10.1152/jappl.1989.66.6.2733.
Arterial O2 saturation (Sao2) decreases in hypoxia in the transition from rest to moderate exercise, but it is unknown whether other several weeks at high altitude SaO2 in submaximal exercise follows the same time course and pattern as that of ventilatory acclimatization in resting subjects. Ventilatory acclimatization is essentially complete after approximately 1 wk at 4,300 m, such that improvement in submaximal exercise SaO2 would then require other mechanisms. On days 2, 8, and 22 on Pikes Peak (4,300 m), 6 male subjects performed prolonged steady-state cycle exercise at 79% maximal O2 uptake (VO2 max). Resting SaO2 rose from day 1 (78.4 +/- 1.6%) to day 8 (87.5 +/- 1.4%) and then did not increase further by day 20 (86.4 +/- 0.6%). During exercise, SaO2 values (mean of 5-, 15-, and 30-min measurements) were 72.7% (day 2), 78.6% (day 8), and 82.3% (day 22), meaning that all of the increase in resting SaO2 occurred from day 1 to day 8, but exercise SaO2 increased from day 2 to day 8 (5.9%) and then increased further from day 8 to day 22 (3.7%). On day 22, the exercise SaO2 was higher than on day 8 despite an unchanged ventilation and O2 consumption. The increased exercise SaO2 was accompanied by decreased CO2 production. The mechanisms responsible for the increased exercise SaO2 require further investigation.
在从静息状态过渡到中等强度运动时，低氧环境下动脉血氧饱和度（Sao2）会下降，但在高原地区进行亚极量运动时，持续数周的其他情况（未明确的内容）下动脉血氧饱和度是否遵循与静息受试者通气适应相同的时间进程和模式尚不清楚。在4300米高度大约1周后，通气适应基本完成，因此亚极量运动时动脉血氧饱和度的改善需要其他机制。在派克斯峰（4300米）的第2天、第8天和第22天，6名男性受试者以最大摄氧量（VO2 max）的79%进行了长时间的稳态自行车运动。静息动脉血氧饱和度从第1天的（78.4±1.6%）升至第8天的（87.5±1.4%），到第20天则未进一步升高（86.4±0.6%）。运动期间，动脉血氧饱和度值（5分钟、15分钟和30分钟测量值的平均值）分别为72.7%（第2天）、78.6%（第8天）和82.3%（第22天），这意味着静息动脉血氧饱和度的所有升高都发生在第1天到第8天，但运动时动脉血氧饱和度从第2天到第8天升高了（5.9%），然后从第8天到第22天进一步升高（3.7%）。在第22天，尽管通气量和耗氧量不变，但运动时的动脉血氧饱和度高于第8天。运动时动脉血氧饱和度的升高伴随着二氧化碳产生量的减少。运动时动脉血氧饱和度升高的机制需要进一步研究。
