Vargas M, León-Velarde F, Monge-C C, Palacios J A, Robbins P A
Departamento de Ciencias Fisiológicas, Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima 100, Peru.
J Appl Physiol (1985). 1998 Mar;84(3):1024-9. doi: 10.1152/jappl.1998.84.3.1024.
High-altitude (HA) natives have blunted ventilatory sensitivities to hypoxia, and it is uncertain whether this blunting is reversible on migration to sea level (SL). To study this, the ventilatory sensitivities to hypoxia of HA natives residing near SL were compared with those of SL natives. Two studies were performed. In study A, 24 HA subjects who had lived above 3,000 m for an average of 14 yr and had been resident at SL for an average of 23 yr were compared with 23 SL controls. In study B, 25 HA subjects who had lived above 3,500 m for at least 20 yr and had been resident at SL for no more than 5 yr were compared with 25 SL controls. Hypoxic sensitivities were assessed by breathing seven progressively more hypoxic gas mixtures that contained progressively more CO2 in an attempt to maintain isocapnia throughout. The ventilatory sensitivities to hypoxia (l . min-1 . %-1 . m-2) did not differ significantly (by analysis of variance) between HA and SL natives in either study A (-0.51 +/- 0.25, mean +/- SD) or study B (-0.34 +/- 0. 15), but the ventilatory sensitivities did differ significantly between the two studies for reasons which are not entirely clear. We conclude that HA natives residing at SL, even if previously at HA for >20 yr, do not maintain the severely blunted hypoxic responses that have been reported in such individuals.
高原（HA）原住民对低氧的通气敏感性降低，目前尚不确定这种降低在迁移至海平面（SL）后是否可逆。为了研究这一问题，对居住在SL附近的HA原住民与SL原住民的低氧通气敏感性进行了比较。进行了两项研究。在研究A中，将平均在海拔3000米以上生活了14年且在SL居住平均23年的24名HA受试者与23名SL对照者进行比较。在研究B中，将至少在海拔3500米以上生活了20年且在SL居住不超过5年的25名HA受试者与25名SL对照者进行比较。通过让受试者呼吸七种逐渐降低氧含量且逐渐增加二氧化碳含量的混合气体来评估低氧敏感性，以试图在整个过程中维持等碳酸血症。在研究A（-0.51±0.25，均值±标准差）和研究B（-0.34±0.15）中，HA和SL原住民之间的低氧通气敏感性（升·分钟-1·%-1·平方米-2）在方差分析中无显著差异，但两项研究之间的通气敏感性确实存在显著差异，原因尚不完全清楚。我们得出结论，居住在SL的HA原住民，即使之前在HA地区生活超过20年，也不会维持此前报道的此类个体严重降低的低氧反应。
