Abstract
The purpose of this study was to assess the effect of two fluid intake protocols on alertness and reaction time before and after fluid intake. Healthy college-age males (n = 12) followed two fluid intake protocols on separate occasions: (1) prescribed fluid (PF) and fluid restricted (FR). In PF, participants were instructed to consume 500 mL of fluid the night prior to and the morning of data collection. In FR, participants were instructed to refrain from the consumption of fluid for 12 h. To assess hydration status, urine specific gravity and urine color were measured. Participants perceived level of thirst and alertness were also recorded. Participants then completed visuomotor reaction time tests using the Dynavision LED board, using both a central visuomotor test and a peripheral visuomotor test (PVRT) prior to (1) and following (2) the ingestion of 100 mL of water. Participants displayed significantly improved PVRT in PF state as compared to FR (PF1 = 1.13 ± 0.16, PF2 = 1.04 ± 0.14; FR1 = 1.27 ± 0.27, FR2 = 1.18 ± 0.20; p = 0.038, ηp2 = 0.363). Both CVRT and PVRT improved over time, following the ingestion of 100 mL of fluid. Participants in the PF state were also significantly more alert than participants in the FR state (PF = 4 ± 2, FR = 5 ± 2; p = 0.019, ES = 0.839). Collectively, perceived alertness and PVRT were negatively impacted by FR.
Highlights
Hydration is a critical component of nutrition and a myriad of evidence has supported that low fluid intake, or hypohydration, results in negative performance and health outcomes [1,2,3]
The extent has not been fully realized in the general population, previous evidence has shown that high plasma tonicity and mild hypohydration are highly prevalent in older adults [5,6]
Urine specific gravity (USG) was significantly higher in the fluid restricted (FR) trial (1.030 ± 0.007) than prescribed fluid (PF) trial (1.010 ± 0.002; p < 0.001; d = 2.02)
Summary
Hydration is a critical component of nutrition and a myriad of evidence has supported that low fluid intake, or hypohydration, results in negative performance and health outcomes [1,2,3]. Recent research has pointed to the impact of hypohydration on several domains of cognition, the impacts of mild hypohydration through relatively short bouts of fluid restriction have demonstrated mixed results [4]. The extent has not been fully realized in the general population, previous evidence has shown that high plasma tonicity and mild hypohydration are highly prevalent in older adults [5,6]. Prevalence of mild hypohydration and the importance of reaction time in the general public and athletic populations indicates a need to further inquire as to how mild hypohydration impacts visuomotor reaction time
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call