Effect of hydration on some orthostatic and haematological responses to head-up tilt
Effect of hydration on some orthostatic and haematological responses to head-up tilt
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水合作用对抬头倾斜的一些直立性和血液学反应的影响
DOI：
10.1007/bf00715003
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
J. Greenleaf
中科院分区：
文献类型：
--
作者：
M. Harrison;L. C. Hill;W. Spaul;J. Greenleaf
进行实验以确定水合状态对 a) 直立反应和 b) 的影响，即在 70‡ 抬头倾斜 (HUT) 期间血管内容量和蛋白质含量的相对变化。 6 名男性接受了 45 分钟的 HUT，然后是仰卧 45 分钟，首先脱水，105 分钟后再次补水。补液后心率持续较低（p<0.01），而仰卧舒张压较高（p<0.02）。脱水 HUT 期间收缩压下降 (p<0.01)，但再水合 HUT 期间收缩压没有下降。补液后体位血液浓度降低（p<0.001），同时血管内白蛋白含量降低（p<0.05）。两名受试者在脱水 HUT 期间经历了严重的晕厥前症状，但在补水 HUT 期间没有出现。因此，限制液体摄入后的补液似乎可以改善直立耐受性。此外，在确定直立耐受性时，血管外水合状态可能比血管内水合状态更重要。
Experiments were undertaken to determine the effects of hydration status on a) orthostatic responses, and on b), relative changes in intravascular volume and protein content, during 70‡ head-up tilt (HUT). Six men underwent 45 min of HUT, preceded by 45 min supine, first dehydrated, and again 105 min later after rehydration with water. Heart rate was consistently lower following rehydration (p<0.01), while supine diastolic pressure was higher (p<0.02). Systolic pressure fell during dehydrated HUT (p<0.01), but not during rehydrated HUT. Postural haemoconcentration, which was reduced after rehydration (p<0.001), was accompanied by a decrease in intravascular albumin content (p<0.05). Two subjects experienced severe presyncopal symptoms during dehydrated HUT, but not during rehydrated HUT. Thus, it appears that rehydration after fluid restriction improves orthostatic tolerance. Furthermore, extravascular hydration status may be more important than intravascular hydration status in determining orthostatic tolerance.