This study investigated (a) differences between males and females for changes in serum, tear, and urine osmolality, hematocrit, and urine specific gravity following acute passive dehydration and (b) assessed the reliability of these biomarkers separately for each sex. Fifteen males (age: 26.3 ± 3.5 years, body mass: 76 ± 7 kg) and 15 females (age: 28.8 ± 6.4 years, body mass: 63 ± 7 kg) completed a sauna protocol twice (5–28 days apart), aiming for 4% body mass loss (BML). Urine, blood, and tear markers were collected pre- and postdehydration, and change scores were calculated. Male BML was significantly greater than that of females in Trial 1 (3.53% ± 0.55% vs. 2.53% ± 0.43%, p < .001) and Trial 2 (3.36% ± 0.66% vs. 2.53% ± 0.44%, p = .01). Despite significant differences in BML, change in hematocrit was the only change marker that displayed a significant difference in Trial 1 (males: 3% ± 1%, females: 2% ± 1%, p = .004) and Trial 2 (males: 3% ± 1%, females: 1% ± 1%, p = .008). Regression analysis showed a significant effect for sex (male) predicting change in hematocrit (β = 0.8, p = .032) and change in serum osmolality (β = −3.3, p = .005) when controlling for BML but not for urinary or tear measures. The intraclass correlation coefficients for females (ICC 2, 1) were highest for change in urine specific gravity (ICC = .62, p = .006) and lowest for change in tear osmolarity (ICC = −.14, p = .689), whereas for males, it was posthematocrit (ICC = .65, p = .003) and post tear osmolarity (ICC = .18, p = .256). Generally, biomarkers showed lower test–retest reliability in males compared with females but, overall, were classified as poor–moderate in both sexes. These findings suggest that the response and reliability of hydration biomarkers are sex specific and highlight the importance of accounting for BML differences.

本研究调查了（a）男性和女性在急性被动脱水后血清、泪液和尿液渗透压、血细胞比容和尿比重变化的差异，以及（b）分别评估了每个性别的这些生物标志物的可靠性。15 名男性（年龄：26.3 ± 3.5 岁，体重：76 ± 7 kg）和 15 名女性（年龄：28.8 ± 6.4 岁，体重：63 ± 7 kg）完成了两次桑拿方案（间隔 5-28 天），目标是减少 4% 的体重 (BML)。在脱水前和脱水后收集尿液、血液和泪液标记物，并计算变化分数。在试验 1 中，男性 BML 显着高于女性（3.53% ± 0.55% vs. 2.53% ± 0.43%，p  < .001）和试验 2（3.36% ± 0.66% vs. 2.53% ± 0.44%，p  = .01）。尽管 BML 存在显着差异，但血细胞比容的变化是试验 1（男性：3% ± 1%，女性：2% ± 1%，p  = .004）和试验 2（男性： 3% ± 1%，女性：1% ± 1%，p  = .008）。回归分析显示，在控制 BML 时，性别（男性）对预测血细胞比容变化（β = 0.8，p  = .032）和血清渗透压变化（β = -3.3，p  = .005）有显着影响，但对尿或尿渗透压没有影响。撕裂措施。女性组内相关系数 (ICC 2, 1) 尿比重变化最高 (ICC = .62, p  = .006)，泪液渗透压变化最低 (ICC = -.14, p  = .689) ，而对于男性，则是血细胞比容（ICC = .65，p  = .003）和泪液渗透压（ICC = .18，p  = .256）。一般来说，与女性相比，男性生物标志物的重测可靠性较低，但总体而言，男性和女性的生物标志物都被归类为差到中等。这些发现表明，水合生物标志物的反应和可靠性具有性别特异性，并强调了考虑 BML 差异的重要性。