Effects of immersion in water containing high concentrations of CO 2 (CO2-water) at thermoneutral on thermoregulation and heart rate variability in humans

Maki Sato, Dominika Kanikowska, Satoshi Iwase, Naoki Nishimura, Yuuki Shimizu, Eric Belin De Chantemele, Takaaki Matsumoto, Yoko Inukai, Yumiko Taniguchi, Akihiro Ogata, Junichi Sugenoya

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Immersion in high concentrations of CO2 dissolved in freshwater (CO2-water) might induce peripheral vasodilatation in humans. In this study, we investigated whether such immersion could affect the autonomic nervous system in humans using spectral analysis of heart rate variability. Ten healthy men participated in this study. Tympanic temperature, cutaneous blood flow and electrocardiogram (ECG) were measured continuously during 20 min of immersion in CO2-water. The ECG was analyzed by spectral analysis of R-R intervals using the maximal entropy method. The decrease in tympanic temperature was significantly greater in CO2-water immersion than in freshwater immersion. Cutaneous blood flow at the immersed site was significantly increased with CO2-water immersion compared to freshwater. The high frequency component (HF: 0.15-0.40 Hz) was significantly higher in CO2-water immersion than in freshwater immersion, but the low frequency (LF: 0.04-0.15 Hz) /high frequency ratio (LF/HF ratio) was significantly lower in CO2-water immersion than in freshwater immersion. The present study contributes evidence supporting the hypothesis that CO2-water immersion activates parasympathetic nerve activity in humans.

Original languageEnglish (US)
Pages (from-to)25-30
Number of pages6
JournalInternational Journal of Biometeorology
Volume53
Issue number1
DOIs
StatePublished - Jan 2009

Keywords

  • CO-water immersion
  • Spectrum analysis
  • Thermoregulation

ASJC Scopus subject areas

  • Ecology
  • Atmospheric Science
  • Health, Toxicology and Mutagenesis

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