Richalet J P, Kéromès A, Carillion A, Mehdioui H, Larmignat P, Rathat C
INSERM U 138, départment de physiologie, facultc de Médécine, Créteil.
Arch Mal Coeur Vaiss. 1989 Aug;82 Spec No 2:49-54.
Exercising in high altitude is impeded during the first days of exposure to altitude hypoxia by the symptoms of Acute Mountain Sickness (AMS). Susceptibility to AMS is independent of endurance training and determined by the sensitivity of carotid chemoreceptors to hypoxemia and induced hyperventilation and tachycardia. Cardiac response to hypoxia is not as well known as ventilatory response, especially at exercise. A group of 138 male alpinists has been explored before their departure to a high altitude expedition using an hypoxic gas mixture (equivalent altitude = 4.800 m), at rest and at exercise (5 minutes at 50 p. 100 maximal O2 consumption). Cardiac response to hypoxia was assessed by the ratio DFc/DSaO2: variation in heart rate (hypoxia - normoxia)/variation in arterial O2 saturation, at rest (r) and during exercise (e). After the expedition, subjects were classified in AMS+ or AMS- group if they suffered or not from severe AMS, and also following their climbing skill. Cardiac response to hypoxia at rest is lower in AMS+ subjects (DFc/DSaO2 = - 0.86 +/- 0.40 nn - 1.% - 1) than in AMS- subjects (-1.12 +/- 0.69, p less than 0.05), but is not linked to the climbing skill. Similar differences were observed at exercise: DFc/DSaO2e = - 0.88 +/- 0.32 (AMS+) and - 1.05 +/- 0.50 (AMS-) (p less than 0.05). Associated with the respiratory response to hypoxia, the cardiac response allows the detection of AMS high-risk subjects and may be used in an much less than aptitude to altitude much greater than test.
在暴露于高原低氧环境的最初几天，急性高原病（AMS）的症状会阻碍在高原进行运动。对AMS的易感性与耐力训练无关，而是由颈动脉化学感受器对低氧血症以及由此引发的过度通气和心动过速的敏感性决定。心脏对低氧的反应不如通气反应那么为人所知，尤其是在运动时。一组138名男性登山运动员在出发进行高原探险前，使用低氧混合气体（等效海拔 = 4800米），在静息和运动状态下（以最大摄氧量的50%运动5分钟）接受了测试。通过心率变化（低氧 - 常氧）/动脉血氧饱和度变化的比值DFc/DSaO2来评估心脏对低氧的反应，分别在静息状态（r）和运动状态（e）下进行。探险结束后，根据受试者是否患有严重AMS以及他们的登山技能，将其分为AMS+组或AMS-组。静息状态下，AMS+受试者的心脏对低氧的反应（DFc/DSaO2 = - 0.86 ± 0.40 nn - 1.% - 1）低于AMS-受试者（-1.12 ± 0.69，p < 0.05），但与登山技能无关。在运动时也观察到了类似的差异：DFc/DSaO2e = - 0.88 ± 0.32（AMS+）和 - 1.05 ± 0.50（AMS-）（p < 0.05）。与对低氧的呼吸反应相关，心脏反应有助于检测AMS高危受试者，并且可用于远超过能力适应性测试的高原测试。
