Iwata Risa, Nakamura Mariko, Takahashi Saeko, Tamai Shinsuke, Fukami Kazuya, Shoji Rie, Sasadai Junpei, Shimizu Reia, Nakajima Kohei
Department of Sports Sciences, Japan Institute of Sports Sciences, Kita-ku, Tokyo, Japan.
Department of Sports Medicine, Japan Institute of Sports Sciences, Kita-ku, Tokyo, Japan.
Physiol Rep. 2025 Sep;13(17):e70540. doi: 10.14814/phy2.70540.
Among the different forms of hydrotherapy, carbon dioxide (CO) water immersion improves peripheral vasodilation and blood flow compared with tap water immersion; however, the heat stress placed on the body through CO water immersion and the appropriate immersion protocols are uncertain. Therefore, this study aimed to compare the thermoregulatory responses during CO and tap water immersions. The participants were 10 male college baseball players. After daily training was completed, intervention was performed for 15 min under three conditions: (1) CO water immersion (CO; 40°C, 1000 ppm), (2) tap water immersion (TAP; 40°C), and (3) seated at rest at room temperature (control [CON]; at 25°C and relative humidity of 60%). Core body temperature (Tcore), skin temperature (Tsk), heart rate (HR), skin blood flow, local sweat rate (LSR), and blood pressure were measured. The Tcore, Tsk, thermal sensation (TS), and HR were significantly higher in the CO and TAP trials than in the CON trial. Compared to tap water immersion, CO water immersion resulted in higher Tcore and LSR values, with moderate to large effect sizes (Tcore: d = 0.52, LSR: d = 0.80). However, thermal discomfort did not increase, suggesting that CO water immersion may increase heat stress without causing any negative effects.
在不同形式的水疗法中，与自来水浸泡相比，二氧化碳（CO）水浸泡可改善外周血管舒张和血流量；然而，通过CO水浸泡施加于身体的热应激以及适当的浸泡方案尚不确定。因此，本研究旨在比较CO水浸泡和自来水浸泡期间的体温调节反应。参与者为10名大学男子棒球运动员。在完成每日训练后，在三种条件下进行15分钟的干预：（1）CO水浸泡（CO；40°C，1000 ppm），（2）自来水浸泡（TAP；40°C），以及（3）在室温下静息就座（对照[CON]；25°C，相对湿度60%）。测量核心体温（Tcore）、皮肤温度（Tsk）、心率（HR）、皮肤血流量、局部出汗率（LSR）和血压。与CON试验相比，CO和TAP试验中的Tcore、Tsk、热感觉（TS）和HR显著更高。与自来水浸泡相比，CO水浸泡导致Tcore和LSR值更高，效应量为中等至大（Tcore：d = 0.52，LSR：d = 0.80）。然而，热不适感并未增加，这表明CO水浸泡可能会增加热应激而不会产生任何负面影响。
