Abstract
Objectives
To assess the effects of hydration status and ice-water dousing on physiological and
performance parameters.
Design
Randomized, crossover.
Methods
Twelve athletes (mean[M] ± standard deviation[SD]; age, 20 ± 1 years; height, 174 ± 8 cm;
body mass, 72.1 ± 11.0 kg; VO2max 53.9 ± 7.3 mL⋅kg−1⋅min−1) completed four trials (euhydrated without dousing, hypohydrated without dousing,
euhydrated with dousing, and hypohydrated with dousing), which involved intermittent
treadmill running (five 15-minute bouts) in the heat (M ± SD; ambient temperature,
34.7 ± 2.1 °C; relative humidity, 46 ± 3%; wet-bulb globe temperature, 28.0 ± 0.4 °C).
Participants also completed four cognitive, power, agility, reaction time, and repeated
sprint performance tests throughout each trial. Heart rate (HR) and rectal temperature
(Trec) were measured continuously. Repeated measures ANOVAs were performed to assess differences
between physiological and performance variables. Alpha was set at ≤0.05, a priori.
Data are reported as mean difference ± standard error (MD ± SE).
Results
HR was significantly lower in euhydrated trials compared to hypohydrated trials, irrespective
of dousing (8 ± 2 bpm; p = 0.001). Dousing did not significantly impact HR (p = 0.455) and there was no interaction between hydration and dousing (p = 0.893). Trec was significantly lower in euhydrated trials compared to hypohydrated trials (0.39 ± 0.05 °C,
p < 0.001), with no effect from dousing alone (p = 0.113) or the interaction of hydration and dousing (p = 0.848). Dousing resulted in improved sprint performance (11 ± 3 belt rotations,
p = 0.007), while hydration status did not (p = 0.235).
Conclusions
Athletes should aim to maintain euhydration during exercise in the heat for improved
physiological function and cooling with ice-water dousing elicits additional performance
benefits.
Keywords
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Article info
Publication history
Published online: May 22, 2021
Accepted:
May 17,
2021
Received in revised form:
April 30,
2021
Received:
July 13,
2020
Identification
Copyright
© 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
