{"title":"低浓度二氧化碳富集与自来水浸泡对被动加热后体温的影响比较。","authors":"Keiji Hayashi","doi":"10.1186/s40101-021-00271-z","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Because carbon dioxide (CO<sub>2</sub>)-enriched water causes cutaneous vasodilation, immersion in CO<sub>2</sub>-enriched water facilitates heat transfer from the body to the water or from the water to the body. Consequently, immersion in CO<sub>2</sub>-enriched water raises or reduces body temperature faster than immersion in fresh water. However, it takes time to dissolve CO<sub>2</sub> in tap water and because the dissolved CO<sub>2</sub> concentration decreases over time, the actual CO<sub>2</sub> concentration is likely lower than the stated target concentration. However, it is unclear whether water containing a lower CO<sub>2</sub> concentration would also cool the body faster than fresh water after body temperature had been increased.</p><p><strong>Methods: </strong>Ten healthy males (mean age = 20 ± 1 years) participated in the study. Participants were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO<sub>2</sub>-enriched water bath at 30 °C to reduce body temperature. The CO<sub>2</sub> concentration was set at 500 ppm. The present study measured cooling time and cooling rate (slope of the regression line relating auditory canal temperature (T<sub>ac</sub>) to cooling time) to assess the cooling effect of CO<sub>2</sub>-enriched water immersion.</p><p><strong>Results: </strong>Immersion in 40 °C tap water caused T<sub>ac</sub> to rise 0.64 ± 0.25 °C in the tap water session and 0.62 ± 0.27 °C in the CO<sub>2</sub>-enriched water session (P > 0.05). During the 30 °C water immersion, T<sub>ac</sub> declined to the baseline within 13 ± 6 min in tap water and 10 ± 6 min in CO<sub>2</sub>-enriched water (P > 0.05). Cooling rates were 0.08 ± 0.06 °C/min in tap water and 0.08 ± 0.04 °C/min in CO<sub>2</sub>-enriched water (P > 0.05).</p><p><strong>Conclusions: </strong>CO<sub>2</sub>-enriched water containing 500 ppm CO<sub>2</sub> did not cool faster than tap water immersion. This suggests that when the water temperature is 30 °C, a CO<sub>2</sub> concentration of 500 ppm is insufficient to obtain the advantageous cooling effect during water immersion after body temperature has been increased.</p>","PeriodicalId":16768,"journal":{"name":"Journal of Physiological Anthropology","volume":"40 1","pages":"20"},"PeriodicalIF":3.1000,"publicationDate":"2021-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8600816/pdf/","citationCount":"0","resultStr":"{\"title\":\"Comparison of low-concentration carbon dioxide-enriched and tap water immersion on body temperature after passive heating.\",\"authors\":\"Keiji Hayashi\",\"doi\":\"10.1186/s40101-021-00271-z\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Background: </strong>Because carbon dioxide (CO<sub>2</sub>)-enriched water causes cutaneous vasodilation, immersion in CO<sub>2</sub>-enriched water facilitates heat transfer from the body to the water or from the water to the body. Consequently, immersion in CO<sub>2</sub>-enriched water raises or reduces body temperature faster than immersion in fresh water. However, it takes time to dissolve CO<sub>2</sub> in tap water and because the dissolved CO<sub>2</sub> concentration decreases over time, the actual CO<sub>2</sub> concentration is likely lower than the stated target concentration. However, it is unclear whether water containing a lower CO<sub>2</sub> concentration would also cool the body faster than fresh water after body temperature had been increased.</p><p><strong>Methods: </strong>Ten healthy males (mean age = 20 ± 1 years) participated in the study. Participants were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO<sub>2</sub>-enriched water bath at 30 °C to reduce body temperature. The CO<sub>2</sub> concentration was set at 500 ppm. The present study measured cooling time and cooling rate (slope of the regression line relating auditory canal temperature (T<sub>ac</sub>) to cooling time) to assess the cooling effect of CO<sub>2</sub>-enriched water immersion.</p><p><strong>Results: </strong>Immersion in 40 °C tap water caused T<sub>ac</sub> to rise 0.64 ± 0.25 °C in the tap water session and 0.62 ± 0.27 °C in the CO<sub>2</sub>-enriched water session (P > 0.05). During the 30 °C water immersion, T<sub>ac</sub> declined to the baseline within 13 ± 6 min in tap water and 10 ± 6 min in CO<sub>2</sub>-enriched water (P > 0.05). Cooling rates were 0.08 ± 0.06 °C/min in tap water and 0.08 ± 0.04 °C/min in CO<sub>2</sub>-enriched water (P > 0.05).</p><p><strong>Conclusions: </strong>CO<sub>2</sub>-enriched water containing 500 ppm CO<sub>2</sub> did not cool faster than tap water immersion. This suggests that when the water temperature is 30 °C, a CO<sub>2</sub> concentration of 500 ppm is insufficient to obtain the advantageous cooling effect during water immersion after body temperature has been increased.</p>\",\"PeriodicalId\":16768,\"journal\":{\"name\":\"Journal of Physiological Anthropology\",\"volume\":\"40 1\",\"pages\":\"20\"},\"PeriodicalIF\":3.1000,\"publicationDate\":\"2021-11-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8600816/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Physiological Anthropology\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1186/s40101-021-00271-z\",\"RegionNum\":4,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"Social Sciences\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physiological Anthropology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1186/s40101-021-00271-z","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Social Sciences","Score":null,"Total":0}
Comparison of low-concentration carbon dioxide-enriched and tap water immersion on body temperature after passive heating.
Background: Because carbon dioxide (CO2)-enriched water causes cutaneous vasodilation, immersion in CO2-enriched water facilitates heat transfer from the body to the water or from the water to the body. Consequently, immersion in CO2-enriched water raises or reduces body temperature faster than immersion in fresh water. However, it takes time to dissolve CO2 in tap water and because the dissolved CO2 concentration decreases over time, the actual CO2 concentration is likely lower than the stated target concentration. However, it is unclear whether water containing a lower CO2 concentration would also cool the body faster than fresh water after body temperature had been increased.
Methods: Ten healthy males (mean age = 20 ± 1 years) participated in the study. Participants were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO2-enriched water bath at 30 °C to reduce body temperature. The CO2 concentration was set at 500 ppm. The present study measured cooling time and cooling rate (slope of the regression line relating auditory canal temperature (Tac) to cooling time) to assess the cooling effect of CO2-enriched water immersion.
Results: Immersion in 40 °C tap water caused Tac to rise 0.64 ± 0.25 °C in the tap water session and 0.62 ± 0.27 °C in the CO2-enriched water session (P > 0.05). During the 30 °C water immersion, Tac declined to the baseline within 13 ± 6 min in tap water and 10 ± 6 min in CO2-enriched water (P > 0.05). Cooling rates were 0.08 ± 0.06 °C/min in tap water and 0.08 ± 0.04 °C/min in CO2-enriched water (P > 0.05).
Conclusions: CO2-enriched water containing 500 ppm CO2 did not cool faster than tap water immersion. This suggests that when the water temperature is 30 °C, a CO2 concentration of 500 ppm is insufficient to obtain the advantageous cooling effect during water immersion after body temperature has been increased.
期刊介绍：
Journal of Physiological Anthropology (JPA) is an open access, peer-reviewed journal that publishes research on the physiological functions of modern mankind, with an emphasis on the physical and bio-cultural effects on human adaptability to the current environment.
The objective of JPA is to evaluate physiological adaptations to modern living environments, and to publish research from different scientific fields concerned with environmental impact on human life.
Topic areas include, but are not limited to:
environmental physiology
bio-cultural environment
living environment
epigenetic adaptation
development and growth
age and sex differences
nutrition and morphology
physical fitness and health
Journal of Physiological Anthropology is the official journal of the Japan Society of Physiological Anthropology.
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