高濃度人工炭酸泉浴による疲労回復効果 －睡眠深度および心拍変動を指標として－高濃度人工炭酸泉浴による疲労回復効果 －睡眠深度および心拍変動を指標として－AA12815481 Effect of bathing on artificial carbon dioxide-rich water on recovery from fatigue as an index of sleep depth and heart rate variability
To examine the effects of bathing in artificial carbon dioxide-rich water (CO2) on recovery from fatigue as an index of sleep depth and heart rate variability, six healthy men were immersed in a CO2 (1000 ppm) bath at a water temperature of 39°C up to the shoulder for 10 min. As a control, each subject bathed in freshwater (FR) under the same conditions. After bathing, each subject slept 7 hours in a climatic chamber set at an ambient temperature of 26°C and relative humidity of 50%. After CO2 bathing, the rectal temperature declinedmore rapidly than after FR bathing, especially in the early stages of sleep. The high frequency (HF) component of heart rate variability as an index of parasympathetic nervous activity during sleep was higher after CO2 bathing than after FR bathing. Sleep latency after CO2 bathing tended to be faster than after FR bathing, and the subjective interrupted sleep time was also reduced following CO2 bathing. Furthermore, the subjective evaluation of sleep quality was higher after CO2 bathing. These results suggest that CO2 bathing induces greater fatigue recovery effects than FR bathing.