Effect of Cold Water Intake During Exercise in Heat on Cognitive Function

Abstract

PURPOSE:The purpose of this study was to examine the effect of cooling treatment by cold water intake before and during exercise in a hot environment on cognitive function.METHODS: Twelve healthy adult men (26.3±4.4 years, 176.2±5.8 cm, 77.2±14.6 kg, 24.8±3.7 kg/m<sup>2</sup>) completed 3 exercise tests; with drinking warm water (36.5°C), with drinking cold water (4°C), or without drinking water. Each test was separated at least 3 days. During each test, they ran on a treadmill for 20 minutes at 75% of their maximal heart rate in 40°C with 40% of humidity. For the drinking conditions, the total volume of drinking was set to 1% of the participant’s weight. Before the test in each drinking condition, they consume 1/3 of the total volume at once. The remaining 2/3 was consumed separately 3 times at six-min interval during exercise. A neuropsychological test using the Stroop Color and Word Test (SCWT) was conducted before and after the exercise to examine the changes of cognitive abilities. Data were analyzed using a two way repeated measures ANOVA.RESULTS: Comparing pre- and post-exercise SCWT, the main effects in words, colors, and words and colors were noticed (p=.000, p=.003, and p=.008, respectively). No differences were found between water drinking conditions.CONCLUSIONS: Overall, a short bout of high-intensity exercise in the hot environment improved cognitive functions, but it was not possible to determine how water temperature and water intake affected cognitive ability. Further research is needed considering the ages and fitness levels of participants.