Fluid Replacement Attenuates Physiological Strain Resulting From Mild Hypohydration Without Impacting Cognitive Performance
Wittbrodt MT, Millard-Stafford M, Sherman RA, Cheatham CC
International journal of sport nutrition and exercise metabolism · 17 citations
How it was studied
- Design
- Controlled clinical trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- University or hospital
- Western Michigan University
Based on 1 listed funder(s).
Publication
- Published
- 2015-03-27 · Int J Sport Nutr Exerc Metab · vol. 25 · issue 5 · pp. 439–447
- Publisher
- Human Kinetics
- Cited
- 19 citations · more than 68% of similar papers · 0.6× the field average
- References
- 15 works
- Access
- Paywalled
- Research areas
- Thermoregulation and physiological responses · Body Composition Measurement Techniques · Diet and metabolism studies
- Keywords
- Medicine, Heart rate, Core temperature, Effects of sleep deprivation on cognitive performance, Fluid replacement, Heat stress, Vigilance (psychology), Cognition, Internal medicine, Animal science, Psychology, Blood pressure, Biology
- MeSH
- humans, dehydration, fluid therapy, exercise, cross-over studies, cognition, sweating, heat-shock response, heart rate, bicycling, adult, male, hot temperature, young adult, sports nutritional physiological phenomena
4 authors
From US
- Matthew T. WittbrodtWestern Michigan University
- Mindy L. Millard-StaffordGeorgia Institute of Technology
- Ross A. ShermanGrand Valley State University
- Christopher C. Cheatham
Abstract
Purpose
The impact of mild hypohydration on physiological responses and cognitive performance following exercise-heat stress (EHS) were examined compared with conditions when fluids were ingested ad libitum (AL) or replaced to match sweat losses (FR).
Methods
Twelve unacclimatized, recreationally-active men (22.2 ± 2.4 y) completed 50 min cycling (60%VO2peak) in the heat (32°C; 65% RH) under three conditions: no fluid (NF), AL, and FR. Before and after EHS, a cognitive battery was completed: Trail making, perceptual vigilance, pattern comparison, match-to-sample, and letter-digit recognition tests.
Results
Hypohydration during NF was greater compared with AL and FR (NF: -1.5 ± 0.6; AL: -0.3 ± 0.8; FR: -0.1 ± 0.3% body mass loss) resulting in higher core temperature (by 0.4, 0.5 °C), heart rate (by 13 and 15 b·min-1), and physiological strain (by 1.3, 1.5) at the end of EHS compared with AL and FR, respectively. Cognitive performance (response time and accuracy) was not altered by fluid condition; however, mean response time improved (p < .05) for letter-digit recognition (by 56.7 ± 85.8 ms or 3.8%; p < .05) and pattern comparison (by 80.6 ± 57.4 ms or 7.1%; p < .001), but mean accuracy decreased in trail making (by 1.2 ± 1.4%; p = .01) after EHS (across all conditions).
Conclusions
For recreational athletes, fluid intake effectively mitigated physiological strain induced by mild hypohydration; however, mild hypohydration resulting from EHS elicited no adverse changes in cognitive performance.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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