Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.
Int J Sport Nutr Exerc Metab. 2010 Apr;20(2):145-53. doi: 10.1123/ijsnem.20.2.145.
It is difficult to describe hydration status and hydration extremes because fluid intakes and excretion patterns of free-living individuals are poorly documented and regulation of human water balance is complex and dynamic. This investigation provided reference values for euhydration (i.e., body mass, daily fluid intake, serum osmolality; M +/- SD); it also compared urinary indices in initial morning samples and 24-hr collections. Five observations of 59 healthy, active men (age 22 +/- 3 yr, body mass 75.1 +/- 7.9 kg) occurred during a 12-d period. Participants maintained detailed records of daily food and fluid intake and exercise. Results indicated that the mean total fluid intake in beverages, pure water, and solid foods was >2.1 L/24 hr (range 1.382-3.261, 95% confidence interval 0.970-3.778 L/24 hr); mean urine volume was >1.3 L/24 hr (0.875-2.250 and 0.675-3.000 L/24 hr); mean urine specific gravity was >1.018 (1.011-1.027 and 1.009-1.030); and mean urine color was > or = 4 (4-6 and 2-7). However, these men rarely (0-2% of measurements) achieved a urine specific gravity below 1.010 or color of 1. The first morning urine sample was more concentrated than the 24-h urine collection, likely because fluids were not consumed overnight. Furthermore, urine specific gravity and osmolality were strongly correlated (r2 = .81-.91, p < .001) in both morning and 24-hr collections. These findings provide euhydration reference values and hydration extremes for 7 commonly used indices in free-living, healthy, active men who were not exercising in a hot environment or training strenuously.
描述水合状态和水合极端情况很困难，因为自由生活个体的液体摄入量和排泄模式记录不佳，且人体水平衡的调节非常复杂且动态。本研究提供了水合正常（即体重、每日液体摄入量、血清渗透压；M +/- SD）的参考值；还比较了初始晨样本和 24 小时采集样本的尿液指标。在 12 天的时间里，对 59 名健康、活跃的男性（年龄 22 +/- 3 岁，体重 75.1 +/- 7.9 公斤）进行了 5 次观察。参与者详细记录了每日食物和液体摄入量以及运动情况。结果表明，饮料、纯水和固体食物的平均总液体摄入量>2.1 L/24 小时（范围 1.382-3.261，95%置信区间 0.970-3.778 L/24 小时）；平均尿量>1.3 L/24 小时（0.875-2.250 和 0.675-3.000 L/24 小时）；平均尿比重>1.018（1.011-1.027 和 1.009-1.030）；平均尿液颜色>或=4（4-6 和 2-7）。然而，这些男性很少（<0-2%的测量值）达到尿比重<1.010 或尿液颜色为 1。首次晨尿样本比 24 小时尿液收集样本更浓缩，可能是因为夜间没有摄入液体。此外，在晨样本和 24 小时采集样本中，尿比重和渗透压均有很强的相关性（r2 =.81-.91，p <.001）。这些发现为在不处于热环境或剧烈运动的情况下自由生活、健康、活跃的男性提供了 7 个常用指标的水合正常参考值和水合极端值。
