Exercise Physiology Laboratory, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA.
Med Sci Sports Exerc. 2018 Nov;50(11):2360-2368. doi: 10.1249/MSS.0000000000001682.
Dehydration (DEH) is believed to impair cognitive performance but which domains are affected and at what magnitude of body mass loss (BML) remains unclear.
To conduct systematic literature review and meta-analysis to determine the effect size (ES) of DEH on cognitive performance and influence of experimental design factors (e.g., DEH > 2% BML).
Thirty-three studies were identified, providing 280 ES estimates from 413 subjects with DEH ranging from 1% to 6% BML. Outcome variables (accuracy, reaction time), cognitive domains, and methods to induce DEH varied. Effect sizes were calculated using standardized mean differences and multivariate meta-analysis.
Impairment of cognitive performance (all domains/outcomes) with DEH was small but significant (ES = -0.21; 95% confidence interval [CI]: -0.31 to -0.11; P < 0.0001) with significant heterogeneity (Q(279) = 696.0, P < 0.0001; I = 37.6%). Tasks of executive function (ES = -0.24; 95% CI: -0.37 to -0.12), attention (ES = -0.52; 95% CI: -0.66 to -0.37), and motor coordination (ES = -0.40 to 95% CI: -0.63 to -0.17) were significantly impaired (P ≤ 0.01) after DEH, and attention/motor coordination was different (P < 0.001) from reaction time specific tasks (ES = -0.10; 95% CI: -0.23 to 0.02). Body mass loss was associated with the ES for cognitive impairment (P = 0.04); consequently, impairment was greater (P = 0.04) for studies reporting >2% BML (ES = -0.28; 95% CI: -0.41 to -0.16) compared with ≤2%; (ES = -0.14; 95% CI: -0.27 to 0.00).
Despite variability among studies, DEH impairs cognitive performance, particularly for tasks involving attention, executive function, and motor coordination when water deficits exceed 2% BML.
进行系统文献回顾和荟萃分析，以确定脱水（DEH）对认知表现的影响大小（ES），以及实验设计因素的影响（例如，DEH > 2%体重损失（BML））。
确定了 33 项研究，提供了 280 项 ES 估计值，这些估计值来自 413 名 DEH 范围为 1%至 6%BML 的受试者。结果变量（准确性、反应时间）、认知域和诱导 DEH 的方法均有所不同。使用标准化均数差和多变量荟萃分析计算效应大小。
DEH 对认知表现（所有域/结果）的损害虽小但显著（ES = -0.21；95%置信区间[CI]：-0.31 至 -0.11；P < 0.0001），异质性显著（Q（279）= 696.0，P < 0.0001；I = 37.6%）。执行功能（ES = -0.24；95%CI：-0.37 至 -0.12）、注意力（ES = -0.52；95%CI：-0.66 至 -0.37）和运动协调（ES = -0.40 至 95%CI：-0.63 至 -0.17）任务的认知能力显著受损（P ≤ 0.01），注意力/运动协调与反应时间特定任务（ES = -0.10；95%CI：-0.23 至 0.02）不同（P < 0.001）。体重损失与认知障碍的 ES 相关（P = 0.04）；因此，报告 >2%BML（ES = -0.28；95%CI：-0.41 至 -0.16）的研究比 ≤2%（ES = -0.14；95%CI：-0.27 至 0.00）的研究中，认知障碍更为严重（P = 0.04）。
尽管研究之间存在差异，但当水缺失超过 2%BML 时，DEH 会损害认知表现，特别是涉及注意力、执行功能和运动协调的任务。
