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Body cooling effects of immersion of the forearms in high-concentration artificial carbonic acid water at 25°C

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Title: Body cooling effects of immersion of the forearms in high-concentration artificial carbonic acid water at 25°C
Authors: Tanaka, Yuuki / Nagano, Hisaho / Taimura, Akihiro
Issue Date: 4-Feb-2020
Publisher: 日本生理人類学会 / Japan Society of Physiological Anthropology
Citation: Journal of physiological anthropology, 39, art.no.2; 2020
Abstract: BACKGROUND: This study examined the effects of immersion in stirred, high-concentration, artificial carbonic acid water on body cooling. METHODS: Seven healthy male students (23 ± 2 years old) participated in the experiment. Signed informed consent was obtained from all subjects before the experiment. The subjects changed into shorts and T-shirts and entered an experimental room (with room temperature controlled at 30 °C and relative humidity maintained at 70%) at least 30 min before starting the experiment. After starting the experiment, the subjects were asked to rest on an exercise bike for 5 min and then pedal for 20 min. The exercise load was set to reach 50% of each subject's presumed maximum oxygen intake at 5 min after starting exercise. Subjects then continued pedaling for 1 min to cool down. After this exercise, subjects sat on a chair and immersed forearms in tap water or artificial carbonic acid water (CO2 water) at 25 °C for 20 min. During immersion, tap water or CO2 water was stirred slowly with a pump. After immersion, subjects rested for 10 min. Skin temperature and skin blood flow (left forearm), as well as heart rate and ear canal temperature, were measured continuously. Thermal sensation and thermal comfort were measured intermittently. RESULTS: Skin blood flow of the immersed forearms was higher in CO2 water than in tap water during immersion. The blood flow in the last 5 min (average at rest was 100%) was significantly higher in CO2 water (290.85 ± 84.81%) than in tap water (104.80 ± 21.99%). Thermal sensation and thermal comfort were not different between conditions. Ear canal temperature significantly declined more in CO2 water (- 0.56 ± 0.31 °C) than in tap water (- 0.48 ± 0.30 °C) during immersion. CONCLUSIONS: Our study suggests that immersion of the forearms in slowly stirred CO2 water at 25 °C reduces core temperature elevated by heat stress or exercise more effectively than does tap water at the same temperature. Immersion of the forearms in stirred CO2 water at 25 °C could be useful as a preventive measure against heat stroke from summer work or exercise.
Keywords: Artificial carbonic acid water / Cooling / Core temperature / Exercise / Heat stroke / Skin blood flow / Skin blood flow / Thermal sensation
URI: http://hdl.handle.net/10069/39674
ISSN: 18806805
DOI: 10.1186/s40101-020-0212-3
Rights: © The Author(s). 2020 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/39674

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