Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760-5007, USA.
Eur J Appl Physiol. 2012 Dec;112(12):4081-9. doi: 10.1007/s00421-012-2390-0. Epub 2012 Apr 6.
The cardiovascular response to standing (sit-to-stand change in heart rate; SSΔHR) is commonly employed as a screening tool to detect hypohydration (body water deficit). No study has systematically evaluated SSΔHR cut points using different magnitudes or different types of controlled hypohydration. The objective of this study was to determine the diagnostic accuracy of the often proposed 20 b/min SSΔHR cut point using both hypertonic and isotonic models of hypohydration. Thirteen healthy young adults (8M, 5F) underwent three bouts of controlled hypohydration. The first bout used sweating to elicit large losses of body water (mass) (>3 % sweat). The second two bouts were matched to elicit 3 % body mass losses (3 % diuretic; 3 % sweat). A euhydration control trial (EUH) was paired with each hypohydration trial for a total of six trials. Heart rate was assessed after 3-min sitting and after 1-min standing during all trials. SSΔHR was compared among trials, and receiver operator characteristic curve analysis was used to determine diagnostic accuracy of the 20 b/min SSΔHR cut point. Volunteers lost 4.5 ± 1.1, 3.0 ± 0.6, and 3.2 ± 0.6 % body mass during >3 % sweat, 3 % diuretic, and 3 % sweat trials, respectively. SSΔHR (b/min) was 9 ± 8 (EUH), 20 ± 12 (>3 % sweat; P < 0.05 vs. EUH), 17 ± 7 (3 % diuretic; P < 0.05 vs. EUH), and 13 ± 11 (3 % sweat). The 20 beats/min cut point had high specificity (90 %) but low sensitivity (44 %) and overall diagnostic accuracy of 67 %. SSΔHR increased significantly in response to severe hypertonic hypohydration and moderate isotonic hypohydration, but not moderate hypertonic hypohydration. However, the 20 beats/min cut point afforded only marginal diagnostic accuracy.
站立时的心血管反应（心率由坐至站的变化；SSΔHR）通常被用作检测脱水（身体水分不足）的筛查工具。尚无研究系统地评估使用不同幅度或不同类型的控制性脱水的 SSΔHR 切点。本研究的目的是使用高渗和等渗脱水模型来确定经常提出的 20 次/分钟 SSΔHR 切点的诊断准确性。13 名健康年轻成年人（8 名男性，5 名女性）接受了三回合的控制性脱水。第一回合使用出汗来引起大量的身体水分（体重）损失（>3%的汗水）。后两回合的失水量与第一回合相同，均为 3%（利尿剂；3%的汗水）。每一轮脱水试验都配对一个正常水合试验（EUH），共进行了六轮试验。在所有试验中，评估 3 分钟坐姿和 1 分钟站立后的心率。比较了不同试验中的 SSΔHR，并使用接收者操作特征曲线分析来确定 20 次/分钟 SSΔHR 切点的诊断准确性。志愿者在 >3%的汗水、3%利尿剂和 3%的汗水试验中分别损失了 4.5±1.1%、3.0±0.6%和 3.2±0.6%的体重。SSΔHR（次/分钟）分别为 9±8（EUH）、20±12（>3%汗水；与 EUH 相比，P<0.05）、17±7（3%利尿剂；与 EUH 相比，P<0.05）和 13±11（3%的汗水）。20 次/分钟的切点具有很高的特异性（90%），但敏感性（44%）低，总体诊断准确性为 67%。SSΔHR 随着严重高渗性脱水和中度等渗性脱水而显著增加，但中度高渗性脱水则没有。然而，20 次/分钟的切点仅提供了边缘诊断准确性。
