Antithrombotic Effect on Hemostasis during Water Immersion at Indifferent Temperature / 日本温泉気候物理医学会雑誌

ABSTRACT

Studies on the effects of heating as well as the mineral components of hot spring water have been conducted to investigate the effects of balneotherapy. However, few studies have been conducted on the effects of hydrostatic pressure and buoyancy during water immersion. Therefore, we investigated the effect of water immersion up to the neck at thermoneutral temperature on hemostatic activity.<br>Nine healthy men aged 22 to 34 were immersed up to the neck in the standing position in thermoneutral water (34.0±0.5°C) for two hours. The heart rate decreased immediately after starting water immersion and remained low during the immersion. Hematocrit values (Ht) of the blood samples taken from the ante-cubital vein decreased by 3.4% in average. The decrease in Ht was more prominent in the blood samples taken from the earlobe (4.0%), suggesting that hemodilution due to fluid shift was stronger in the upper part of the body. The time until euglobulin clot lysis shortened immediately after starting the immersion. Although fibrinolytic activity was enhanced, the concentration of tissue plasminogen activator (t-PA) antigen in the blood decreased gradually during the immersion and tended to return to the original level 30 minutes after immersion. A larger decrease in the concentration of plasminogen activator inhibitor-1 (PAI-1) antigen in the blood was observed immediately after starting the immersion, and it remained low for 30 minutes after immersion. An increase in fibrinolytic activity due to the decrease in PAI-1, not in t-PA, was observed during water immersion at thermoneutral temperature and the activation of fibrinolytic system without activation of the coaguration system was also observed.