Department of Sport Science, Medical Section, University Innsbruck, Innsbruck, Austria.
PLoS One. 2013 Aug 27;8(8):e73185. doi: 10.1371/journal.pone.0073185. eCollection 2013.
The present study determined the association between body fluid variation and the development of acute mountain sickness (AMS) in adults.
Forty-three healthy participants (26 males and 17 females, age: 26 ± 6 yr, height: 174 ± 9 cm, weight: 68 ± 12 kg) were passively exposed at a FiO2 of 12.6% (simulated altitude hypoxia of 4500 m, PiO2 = 83.9 mmHg) for 12-h. AMS severity was assessed using the Lake Louise Score (LLS). Food and drink intakes were consumed ad libitum and measured; all urine was collected. Before and after the 12-h exposure, body weight and plasma osmolality were measured and whole-body bioimpedance analysis was performed.
The overall AMS incidence was 43% (38% males, 50% females). Participants who developed AMS showed lower fluid losses (3.0 ± 0.9 vs. 4.5 ± 2.0 ml/kg/h, p = 0.002), a higher fluid retention (1.9 ± 1.5 vs. 0.6 ± 0.8 ml/kg/h, p = 0.022), greater plasma osmolality decreases (-7 ± 7 vs. -2 ± 5 mOsm/kg, p = 0.028) and a larger plasma volume expansion (11 ± 10 vs. 1 ± 15%, p = 0.041) compared to participants not developing AMS. Net water balance (fluid intake--fluid loss) and the amount of fluid loss were strong predictors whether getting sick or not (Nagelkerkes r(2) = 0.532). The LLS score was related to net water balance (r = 0.358, p = 0.018), changes in plasma osmolality (r = -0.325, p = 0.033) and sodium concentration (r = -0.305, p = 0.047). Changes in the impedance vector length were related to weight changes (r = -0.550, p<0.001), fluid intake (r = -0.533, p<0.001) and net water balance (r = -0.590, p<0.001).
Participants developing AMS within 12 hours showed a positive net water balance due to low fluid loss. Thus measures to avoid excess fluid retention are likely to reduce AMS symptoms.
本研究旨在确定体液变化与成年人高原反应（AMS）发展之间的关系。
43 名健康参与者（26 名男性和 17 名女性，年龄：26±6 岁，身高：174±9cm，体重：68±12kg）在 FiO2 为 12.6%（模拟海拔 4500 米的缺氧，PiO2=83.9mmHg）的条件下被动暴露 12 小时。使用路易湖评分（LLS）评估 AMS 严重程度。随意摄入食物和饮料并进行测量；收集所有尿液。在 12 小时暴露前后，测量体重和血浆渗透压，并进行全身生物阻抗分析。
AMS 的总体发生率为 43%（男性 38%，女性 50%）。发生 AMS 的参与者表现出较低的液体流失（3.0±0.9 与 4.5±2.0ml/kg/h，p=0.002），更高的液体潴留（1.9±1.5 与 0.6±0.8ml/kg/h，p=0.022），更大的血浆渗透压下降（-7±7 与 -2±5mOsm/kg，p=0.028）和更大的血浆容量扩张（11±10 与 1±15%，p=0.041），与未发生 AMS 的参与者相比。净水平衡（液体摄入-液体流失）和液体流失量是判断是否生病的重要预测因素（Nagelkerkes r(2)=0.532）。LS 评分与净水平衡（r=0.358，p=0.018）、血浆渗透压变化（r=-0.325，p=0.033）和钠浓度变化（r=-0.305，p=0.047）相关。阻抗向量长度的变化与体重变化（r=-0.550，p<0.001）、液体摄入（r=-0.533，p<0.001）和净水平衡（r=-0.590，p<0.001）相关。
在 12 小时内发生 AMS 的参与者由于液体流失较少，表现出正的净水平衡。因此，避免过度液体潴留的措施可能会减轻 AMS 症状。
