Deuster P A, Doubt T J, Ryan C J, Montgomery L C, Haberman K J
Department of Military Medicine, Naval Medical Research Institute, Bethesda, Maryland 20814-4799.
Undersea Biomed Res. 1989 Nov;16(6):427-37.
To compare fluid and ion changes during cold (25 degrees C) and thermoneutral head-out immersion (HOI) 9 men were studied under 4 resting conditions lasting 3 h: 2 in 35 degrees C and 2 in 25 degrees C water. At each temperature, subjects consumed 250 ml of either water or a 7% glucose polymer solution every hour to evaluate possible differences in fluid composition. Plasma volume increased by 3.9% for 35 degrees C and decreased by 9.7% for 25 degrees C HOI after 3 h. Urine flow increased significantly during HOI, but there were no differences between water temperatures (35 degrees C: 8.37 +/- 0.44; 25 degrees C: 9.55 +/- 0.57 ml.min-1). Free water clearance and urinary sodium excretion were also elevated during HOI, but water temperature did not alter the magnitude of the response. No HOI-induced kaliuresis was noted. Finally, there was a significant cold-induced increase in serum potassium and sodium, but this reflected largely the decrease in plasma volume. In sum, differences in water temperature seemed to have minimal influence on fluid and cation changes, an indication that immersion is the primary stimulus. Whether greater differences would be noted with colder water remains to be determined.
为比较冷环境（25摄氏度）和热中性头浸式（HOI）过程中的液体和离子变化，对9名男性在4种持续3小时的静息条件下进行了研究：2种条件下处于35摄氏度的水中，2种条件下处于25摄氏度的水中。在每个温度下，受试者每小时饮用250毫升水或7%的葡萄糖聚合物溶液，以评估液体成分可能存在的差异。3小时后，35摄氏度时血浆量增加了3.9%，25摄氏度HOI时血浆量减少了9.7%。HOI期间尿流量显著增加，但水温之间无差异（35摄氏度：8.37±0.44；25摄氏度：9.55±0.57毫升·分钟-1）。HOI期间自由水清除率和尿钠排泄也升高，但水温并未改变反应的幅度。未观察到HOI诱导的尿钾增多。最后，冷环境导致血清钾和钠显著增加，但这主要反映了血浆量的减少。总之，水温差异似乎对液体和阳离子变化影响极小，这表明浸入是主要刺激因素。水温更低时是否会有更大差异仍有待确定。
