Hypoxia, Hypobaria, and Exercise Duration Affect Acute Mountain Sickness
Hypoxia, Hypobaria, and Exercise Duration Affect Acute Mountain Sickness
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DOI：
10.3357/amhp.4266.2015
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发表时间：
2015-07-01
影响因子：
0.9
通讯作者：
Muza, Stephen R.
中科院分区：
文献类型：
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作者：
DiPasquale, Dana M.;Strangman, Gary E.;Muza, Stephen R.
前言：本研究同时量化了常压低氧(NH)、低压低氧(HH)、运动持续时间和暴露时间对急性高原病严重程度(AMS-C)的影响。方法：36名受试者(27.7+/-7.8岁)参加了部分重复测量研究，完成了六种条件中的两种：常压常氧(NN：300m/984 ft当量)、NH或HH(PO2=91 mm Hg；4400 m/14,436 ft当量)，结合中等强度自行车10或60分钟。受试者完成环境症状问卷调查，分别在暴露前、暴露后1.5h、暴露后4h和暴露后1.5h测量血氧饱和度(SpO2)。我们以NH、HH和长期锻炼为指标变量，以AMS-C为结果变量，对暴露时间进行聚类调整标准差的多元线性回归模型。以SpO2和AMS-C评分作为协变量。结果：NH和HH导致AMS-C显著递增，而NN则不是。HH对AMS-C的影响与NH显著不同，HH的AMS-C是NH的1.6倍。HH导致AMS-C显著升高，与运动持续时间无关，而NH仅与较长时间的运动相结合。讨论：AMS-C的升高分别与NH、HH和长时间运动独立相关，HH对AMS-C的影响更严重。这表明，低氧可能会影响AMS的发展，超过单独低氧诱导的水平。这进一步表明，在研究AMS时，NH和HH可能不能互换，运动持续时间可能会影响生理反应。
INTRODUCTION: This study simultaneously quantified the effects of normobaric hypoxia (NH), hypobaric hypoxia (HH), exercise duration, and exposure time on acute mountain sickness severity (AMS-C).METHODS: Thirty-six subjects (27.7 +/- 7.8 yr) participated in a partial repeated measures study, completing two of six conditions: normobaric normoxia (NN: 300 m/984 ft equivalent), NH or HH (PO2 = 91 mmHg; 4400 m/14,436 ft equivalent), combined with moderate intensity cycling for 10 or 60 min. Subjects completed the Environmental Symptoms Questionnaire and oxygen saturation (SpO2) was measured before, 1.5 h, 4 h, and 6.5 h into an 8-h exposure, and 1.5 h post-exposure. We fit multiple linear regression models with cluster adjusted standard errors on the exposure times using NH, HH, and long exercise as indicator variables, and AMS-C as the outcome variable. The SpO2 and pre-exposure AMS-C score were used as covariates.RESULTS: NH and HH led to substantial and progressively increasing AMS-C, but NN did not. The effect of HH on AMS-C was significantly different from NH, with AMS-C in HH being 1.6 times higher than in NH. HH led to significantly increasing AMS-C, regardless of the exercise duration, while NH only did so in combination with longer exercise.DISCUSSION: Increases in AMS-C were each independently related to NH, HH, and long duration exercise, with HH affecting AMS-C more severely. This suggests that hypobaria may affect AMS development above the level induced by hypoxia alone. This further suggests that NH and HH may not be interchangeable for studying AMS and that exercise duration may impact physiological responses.