2025-10-22 カリフォルニア大学リバーサイド校(UCR)
<関連情報>
- https://news.ucr.edu/articles/2025/10/22/being-fit-may-help-body-beat-dehydration
- https://www.sciencedirect.com/science/article/pii/S0031938425003403
実験用ハツカネズミにおける急性全水分欠乏の自発運動行動と体重に対する異なる影響 Differential effects of acute total water deprivation on voluntary exercise behavior and body mass in laboratory house mice
Nicole E. Schwartz, Melanie R. Alva, Theodore Garland Jr.
Physiology & Behavior Available online: 21 October 2025
DOI:https://doi.org/10.1016/j.physbeh.2025.115139
HIGHLIGHTS
- Dehydration can adversely affect human athletic and cognitive performance
- We studied mice from 4 Control and 4 High Runner (HR) lines bred for wheel running
- Adults were given 6 days of wheel access, then half were water-deprived for 1 day
- HR mice of both sexes significantly increased the revolutions run over 24 h
- We speculate that the increase in running may be attributable to reward substitution
Abstract
Various studies have demonstrated adverse effects of dehydration on human athletic and cognitive performance, but most are limited in scope. Moreover, few have studied such effects on voluntary exercise. The purpose of this study was to evaluate the effects of 24 hours of water deprivation on voluntary wheel-running behavior (a model for human voluntary exercise) and body mass in laboratory house mice. To increase the probability of detecting the effects of water deprivation, we studied mice from four replicate High Runner (HR) lines that have been bred for high levels of wheel running. Both sexes of HR mice run ∼3-fold more revolutions/day than the four non-selected Control (CON) lines, have increased motivation for wheel running and an increased capacity for aerobic exercise (i.e., ability), and will run voluntarily at speeds nearer to their aerobic capacity. Adults of both sexes were given 6 days of wheel access, as in the routine selective breeding protocol. At the end of day 6, water bottles were removed for ½ of the mice and a 7th day of wheel access was allowed. As expected, body mass significantly decreased in all groups that experienced 24 hours without water. As compared with days 5 and 6, wheel-running distance did not significantly change in mice from CON or HR lines with ad lib water, nor did it change in the water-deprived CON mice. However, water-deprived HR mice of both sexes significantly increased the number of revolutions run over 24 hours. Given that wheel running is voluntary, presumably because it provides a rewarding experience, we speculate that the significant increase in running after water removal in HR mice may be attributable to “reward substitution,” in which mice replace the reward provided by drinking water (a primary drive) with the rewards derived from running (which may also be a biological drive). Alternatively, mice may have instinctually been attempting to find water, but only those from HR lines have sufficient physical abilities to increase running in spite of adverse effects of dehydration.
