Kovtun Lyudmila T, Voevoda Mikhail I
Federal State Budgetary Institution "Research Institute of Physiology and Fundamental Medicine", Siberian Branch, Russian Academy of Medical Sciences, Novosibirsk, Russia.
Int J Circumpolar Health. 2013 Aug 5;72. doi: 10.3402/ijch.v72i0.21574. eCollection 2013.
Hypoxia is the reduction of oxygen availability due to external or internal causes. There is large individual variability of response to hypoxia.
The aim of this study was to define individual and typological features in susceptibility to hypoxia, its interrelation with hypoxic and hypercapnic ventilatory responses (HVR and HCVR, respectively) and their changes after cold acclimation.
Twenty-four healthy men were tested. HVR and HCVR were measured by the rebreathing method during hypoxic and hypercapnic tests, respectively. These tests were carried out in thermoneutral conditions before and after cold exposures (nude, at 13°C, 2 h daily, for 10 days). Susceptibility to hypoxia (sSaO2) was determined as haemoglobin saturation slope during hypoxic test.
It was found that HVR and HCVR significantly increased and susceptibility to hypoxia (sSaO2) tended to decrease after cold acclimation. According to sSaO2 results before cold exposures, the group was divided into 3: Group 1--with high susceptibility to hypoxia, Group 2--medium and Group 3--low susceptibility. Analysis of variances (MANOVA) shows the key role of susceptibility to hypoxia and cold exposures and their interrelation. Posterior analysis (Fisher LSD) showed significant difference in susceptibility to hypoxia between the groups prior to cold acclimation, while HVR and HCVR did not differ between the groups. After cold acclimation, susceptibility to hypoxia was not significantly different between the groups, while HCVR significantly increased in Groups 1 and 3, HVR significantly increased in Group 3 and HCVR, HVR did not change in Group 2.
Short-term cold exposures caused an increase in functional reserves and improved oxygen supply of tissues in Group 1. Cold exposure hypoxia has caused energy loss in Group 3. Group 2 showed the most appropriate energy conservation reaction mode to cold exposures. No relation was found between the thermoregulation and the susceptibility to hypoxia.
缺氧是由于外部或内部原因导致的氧气供应减少。个体对缺氧的反应存在很大差异。
本研究旨在确定缺氧易感性的个体和类型特征，其与缺氧和高碳酸通气反应（分别为HVR和HCVR）的相互关系以及冷适应后它们的变化。
对24名健康男性进行测试。分别在缺氧和高碳酸测试期间通过再呼吸法测量HVR和HCVR。这些测试在冷暴露前后的热中性条件下进行（裸体，13°C，每天2小时，共10天）。缺氧易感性（sSaO2）被确定为缺氧测试期间的血红蛋白饱和度斜率。
发现冷适应后HVR和HCVR显著增加，缺氧易感性（sSaO2）趋于降低。根据冷暴露前的sSaO2结果，将该组分为3组：第1组——对缺氧高度敏感，第2组——中等敏感，第3组——低敏感。方差分析（MANOVA）显示了缺氧易感性和冷暴露及其相互关系的关键作用。事后分析（Fisher LSD）显示冷适应前各组之间在缺氧易感性方面存在显著差异，而各组之间的HVR和HCVR没有差异。冷适应后，各组之间的缺氧易感性没有显著差异，而第1组和第3组的HCVR显著增加，第3组的HVR显著增加，第2组的HCVR和HVR没有变化。
短期冷暴露导致第1组的功能储备增加，组织的氧气供应得到改善。冷暴露缺氧导致第3组的能量损失。第2组显示出对冷暴露最适当的能量保存反应模式。未发现体温调节与缺氧易感性之间的关系。
