Abstract
Background
Cognitive function, including executive function (EF)-related capacities (eg, working
memory, inhibitory and attentional control), has been linked to adherence to healthy
lifestyle behaviors. Dehydration is associated with impaired cognitive function, whereas
improvements in hydration status may improve inhibitory and attentional performance.
No systematic reviews have examined the effects of both dehydration and euhydration
on EF.
Objective
The objectives of this systematic review are to examine studies that have investigated
the spectrum of hydration status and EF in adults, and to identify future research
needs.
Design
The review was conducted according to the 2015 Preferred Reporting Items for Systematic
Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines. The database search was
initially conducted on May 12, 2019 and then updated on April 26, 2020. Databases
searched included PubMed, Medline, Psyc Info, SCOPUS, Proquest, and ISI Web of Science.
Data extraction included the following: method used to assess de/hydration status,
study design, participant characteristics, EF tasks and domain, and results. Article
quality ratings were performed on included studies using the Academy of Nutrition
and Dietetics Quality Rating Checklist.
Participants/Setting
Studies done with healthy or diseased adults, aged older than 18 years, in any setting,
were included. Studies of individuals with disease states that impact fluid balance
or require fluid restrictions as treatments were excluded.
Main Outcome Measure
All EF-related outcomes were included, such as working memory, inhibitory control,
task switching, and attention.
Results
Four thousand eight hundred thirty-three articles were screened using title/abstracts.
Seventy-one full-text articles were assessed for eligibility; 33 were included (26
included investigations of dehydration; 27 included investigations of rehydration/euhydration)
with 3,636 participants across all studies. Little consistency was found across outcomes.
Roughly half of the available studies suggested unclear or neutral EF effects, and
half suggested effects on EF domains, particularly working memory, inhibitory control,
and attention. Studies including a euhydration condition were slightly more likely
to demonstrate improvements to EF capacities.
Conclusions
Overall, there is a strong need for consistent methodological approaches and a greater
number of long-term (ie, >3 days) studies of dehydration and euhydration and EF.
Keywords
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Biography
B. Katz is an assistant professor, Department of Human Development and Family Science, Virginia Tech, Blacksburg, VA.
Biography
K. Airaghi is a graduate research assistant, Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA.
Biography
B. Davy is a professor, Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA.
Article info
Publication history
Published online: February 03, 2021
Accepted:
December 21,
2020
Received:
May 8,
2020
Footnotes
Supplementary materials: Figure 2 is available at www.jandonline.org
STATEMENT OF POTENTIAL CONFLICT OF INTEREST No potential conflict of interest was reported by the authors.
Identification
Copyright
© 2021 by the Academy of Nutrition and Dietetics.
