著者

和田 匡史 兵頭 洋樹 地神 裕史 土居 裕和 山本 憲志

出版者

国士舘大学理工学部

雑誌

国士舘大学理工学部紀要 = TRANSACTIONS OF THE KOKUSHIKAN UNIVERSITY SCHOOL OF SCIENCE AND ENGINEERING (ISSN:18824013)

巻号頁・発行日

vol.14, pp.159-164, 2021-03-31

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Bathing and sleep play important roles in physical recovery of athletes. Hot spring water containing high concentration carbon dioxide (CO_2 ≥ 1000 ppm) has long been applied to the patients suffering from cardiovascular diseases in balneotherapy. Clinical observations reported various effects of CO_2-hot spring immersion on human body, such as flushing of the skin, skin blood flow improvements, decrease of blood catecholamine levels,and heart rate reduction. The heart rate reduction by CO_2-water immersion might be induced by neuronal information generated in the skin [N. Yamamoto et al, 2007]. The purpose of this study is to examine whether artificial CO_2 hot water immersion facilitates physical recovery in competitive swimmers. Fourteen healthy college competitive swimmers participated in this study. The participants performed anaerobic exercise. Immediately after the exercise, they immersed their whole bodies into tap-water or artificial CO_2-water at 38 degrees Celsius for 10 minutes. To measure the sleep-wake cycle, accelerometers (FS-760 and 770, ACOS, Japan) was used. The sleep-wake data were analyzed by circadian rhythm analysis software (SleepSign Act2, KISSEI COMTEC, Japan). Sleep variables analyzed included time in bed, sleep period time, total sleep time, sleep efficiency, and sleep latency. Blood lactate concentration (BLa) was measured by Lactate analyzer (Lactate Pro2LT-1730, Arkray, Japan). BLa in recovery period was significantly lower in CO_2-water immersion than in tap-water immersion (20 min after the exercise 2.4 ± 0.8 vs 2.7 ± 0.5 mmol, p<0.05, 25 min after the exercise 1.9 ± 0.6 vs 2.6 ± 0.8 mmol, p<0.05, 30min after the exercise 1.8 ± 0.4 vs 2.4 ± 0. mmol, p<0.05,). Sleep latency was significantly shorter in CO_2-water immersion than in tap-water immersion (7.8 ± 2.3 min vs 16.5 ± 3.8 min, p <0.05). Sleep efficiency was significantly higher in CO_2-water immersion than in tap-water immersion (90.3 ± 3.5% vs 83.2 ± 4.6%, p<0.05). Therefore, these results raise the possibilitythat hyperthemia, i.e. body core temperature raise, induced by CO_2-water immersion leads to deep sleep. Deep sleep after the CO_2-water immersion seems to be extremely useful in the physical recovery from fatigue. The rapid decrease in BLa in the CO_2-water immersion suggests efficient physical recovery after anaerobic exercise. Therefore, it was suggested that CO_2-water immersion is effective for physical recovery.