The Effect of Small Changes in Hydration on Cognition

Study Overview
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Brief Summary
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The aim of this study is to determine whether drinking plain water when mildly dehydrated benefits cognitive performance and mood. Volunteers undergo a dehydration protocol designed to result in minor dehydration. While some participants receive two 150ml drinks of water others do not. Differences in cognitive functioning are assessed.

Detailed Description
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As an essential nutrient, an inadequate intake of water has negative consequences: without a source of water death will occur in days. When Benton and Young (2015) reviewed the topic they concluded that in healthy adults, mild dehydration (in the range of a loss of 2% body mass) had been found to adversely influence mood and cognition. However, it is unclear at what degree of hypohydration these effects begin to emerge. This study was designed to determine whether small changes in hydration, of the level that might occur on a day to day basis, influence cognition and mood. During a dehydration protocol (sitting in a room heated to 30 degrees for four hours) young adult participants receive either drink two 150ml cups of water or nothing. Effects on memory, attention and mood are monitored.

Official Title
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How do Small Changes in Hydration Influence Cognition: A Mechanistic Investigation

Conditions
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Cognition, Hydration

Intervention / Treatment
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* Dietary Supplement: Water


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: In good general health i.e. no major health condition such as diabetes BMI < 30 Exclusion Criteria: Not on blood pressure medication or blood thinning medication such as aspirin - No learning difficulty such as dyslexia Diabetes Gastro-intestinal disease High BMI Cholesterol and BP Smoker Dyslexic/dyspraxic Depression or history of depression or other psychiatric disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Drink water<br>Participants will receive two 150ml drinks of water during the dehydration protocol | Dietary Supplement: Water<br>* Participants will receive two cups of 150ml plain water<br>|
| No Intervention: Drink nothing<br>Participants will drink nothing during the dehydration protocol | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Episodic memory - list of 30 words | Participants listen to a list of 30 words presented using a tape recorder. The words are of similar difficulty and matched for the number of syllables and frequency with which they occur in English. The subjects are asked to recall and write down as many words as possible. The difference in the total number of words remembered from baseline (before the intervention) is analysed. | change from 0 to 180 minutes after the start of the dehydration protocol | 
| Focused attention - Eriksen Flanker Task | The Arrow Flankers test measures the ability to direct attention and ignore peripheral information. Participants are required to indicate whether the middle arrow is pointing to the right or left by pressing the corresponding arrow on the keyboard. Either side of the central arrow are distractors. Both the average reaction times (in milliseconds) and accuracy are recorded. The difference in performance from baseline (before the intervention) is analysed. | change from 0 to 180 minutes after the start of the dehydration protocol | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thirst (Participants rate their thirst) | Participants rate their thirst | change from 0 to 180 minutes after the start of the dehydration protocol |