The Effects of Hydration Status on Cognitive Performances among Young Adults in Hebei, China: A Randomized Controlled Trial (RCT).

Background: Dehydration may affect cognitive performances as water accounts for 75% of brain mass. The purpose of this study is to investigate the effects of dehydration and water supplementation on cognitive performances, and to explore the changes of brain structures and functions using MRI. Methods and Analysis: A double-blinded randomized controlled trial has been designed and will be implemented among 64 college students aged 18⁻23 years from Baoding, China. Subjects will be asked to restrict water for 36 h. The first morning urine will be collected and urine osmolality measured. The fasting blood samples will be collected and osmolality and copeptin will be measured. Three MRI sequences, including fMRI, ASL and 3D BRAVO will be taken to observe the changes of whole brain volume, ventricular volume, BOLD response and the cortex thickness. Cognitive performances and mood will be performed with software and questionnaires, respectively. Subjects in the water supplementation groups 1, 2, 3 will drink 200, 500 and 1000 mL of water, respectively, while subjects in the no water supplementation group will not drink any water. After 90 min, urine and blood samples, MRI scans, cognitive performances and mood will be performed. One-way ANOVA will be used to study the differences among groups. Ethics and Dissemination: The study protocol has been approved by the Peking University Institutional Review Committee. Ethical approval project identification code is IRB00001052-16071. Results will be published according to the CONSORT statement and will be reported in peer-reviewed journals.