Faculty of Biology and Medicine, ISSUL, Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland.
National Centre of Nordic-Ski, Research and Performance, Prémanon, France.
Eur J Appl Physiol. 2017 Dec;117(12):2401-2407. doi: 10.1007/s00421-017-3726-6. Epub 2017 Sep 27.
Normobaric hypoxia (NH) is used as a surrogate for hypobaric hypoxia (HH). Recent studies reported physiological differences between NH and HH. Baroreflex sensitivity (BRS) decreases at altitude or following intense training. However, until now no study compared the acute and chronic changes of BRS in NH vs. HH. First, BRS was assessed in 13 healthy male subjects prior and after 20 h of exposure at 3450 m (study 1), and second in 15 well-trained athletes prior and after 18 days of "live-high train-low" (LHTL) at 2250 m (study 2) in NH vs. HH. BRS decreased (p < 0.05) to the same extent in NH and HH after 20 h of hypoxia and after LHTL. These results confirm that altitude decreases BRS but the decrease is similar between HH and NH. The persistence of this decrease after the cessation of a chronic exposure is new and does not differ between HH and NH. The previously reported physiological differences between NH and HH do not appear strong enough to induce different BRS responses.
常压低氧（NH）常被用作模拟高原低氧（HH）。最近的研究报告称，NH 和 HH 之间存在生理差异。在海拔高度或经过强烈训练后，血压反射敏感性（BRS）会降低。然而，到目前为止，还没有研究比较 NH 和 HH 中的 BRS 的急性和慢性变化。首先，在海拔 3450 米处暴露 20 小时前后，对 13 名健康男性进行了 BRS 评估（研究 1），其次，在 NH 与 HH 中，对 15 名训练有素的运动员进行了 18 天的“高住低练”（LHTL）前后的 BRS 评估（研究 2）。在 20 小时的缺氧和 LHTL 后，NH 和 HH 中的 BRS 均出现相同程度的下降（p<0.05）。这些结果证实，海拔高度会降低 BRS，但在 HH 和 NH 之间，这种下降是相似的。慢性暴露停止后，这种下降仍然存在，且在 HH 和 NH 之间没有差异，这是新的发现。NH 和 HH 之间先前报道的生理差异似乎不够强烈，不足以引起不同的 BRS 反应。
