Self-Reported Changes in Thirst and Alertness during Variable Prescribed Fluid Intake

Background: Maintaining euhydration is beneficial for health, safety, and physical performance [1]; however, it may also improve subjective feelings [2, 3]. Objective: The aim of this study was to evaluate the relationship between changes in self-reported thirst and alertness in people undergoing changes in drinking water volume. Methods: Subjects (mean ± SD) (n = 115, 59 males, 32 ± 10 years; 24.6 ± 4.4 kg·m−2) visited the lab 3 times over 10 days: V1, a baseline visit prior to participants were drinking ad libitum; V2, following 3 days of fluid restriction (1 L·d−1, 250 mL was consumed in the morning prior to the visit); and V3, the morning following a prescribed increase in water intake. The increase in water intake at V3 varied by group assignment: control group (CON) maintained 250 mL, while LOW and HIGH groups (n = 45 each) consumed 496 ± 82 mL and 878 ± 125 mL, respectively. At each visit, subjects indicated on an open-ended visual analog scale (VAS) how thirsty and alert they felt and were measured in millimeters (mm). Four, two-way ANOVAs (group × visit) for change in thirst and alertness between V1–V2 and V2–V3 were completed. A repeated-measures correlation (rrm) procedure was completed for change in alertness and thirst from V1 to V2 and V2 to V3 [4]. The study was approved by the University of Wyoming’s Institutional Review Board (protocol #20160524EJ01208), and all subjects provided written informed consent. Results: Groups were similar at baseline (V1) for fluid intake, thirst, and alertness (all p ≥ 0.17). Fluid restriction (V2) resulted in a main effect of visit for thirst and alertness (both p < 0.01), with no main effect of group. Thirst increased (35 ± 35 mm) and alertness decreased (−19 ± 31 mm) from V1 to V2. The prescribed increase in water intake (V3) revealed a significant interaction of visit and group for thirst and alertness (both p < 0.01) (Table 1). Independent-samples t tests with a Bonferroni correction revealed that HIGH reduced thirst (−38 ± 37 mm) and increased alertness (18 ± 25 mm), while no change was observed for LOW (thirst, −7 ± 37 mm; alertness −1 ± 24 mm) and CON (thirst, −6 ± 23 mm; alertness 0 ± 23 mm; all p < 0.01) (Fig. 1). There was no difference between LOW and CON (both p > 0.92). Repeated-measures correlation analysis revealed an inverse relationship between change in alertness and thirst (rrm [114] = −0.53, 95% CI [−0.65, −0.38], p < 0.01). Conclusion: A reduction in water intake resulted in an increase in thirst and decrease in alertness. Following 3 days of fluid restriction, 750–1,000 mL of water intake was needed to decrease thirst and increase alertness. Overall, an inverse relationship was observed between self-reported thirst and alertness.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Self-Reported Changes in Thirst and Alertness during Variable Prescribed Fluid Intake ; volume:77 ; number:Suppl 4 ; year:2022 ; pages:28-29 ; extent:2 ; Annals of nutrition & metabolism ; 77, Heft Suppl 4 (2022), 28-29 (gesamt 2)

Contributors, Places and Time

• Creator: Yoder, Hillary A. ; Huffman, Ainsley E. ; McCullough, Shane ; Johnson, Evan C.

Further information

• DOI: 10.1159/000521066
• URN: urn:nbn:de:101:1-2022030923303087792710
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:32 AM CEST