Park Y H, Iwamoto J, Tajima F, Miki K, Park Y S, Shiraki K
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
J Appl Physiol (1985). 1988 May;64(5):1916-22. doi: 10.1152/jappl.1988.64.5.1916.
The present work was undertaken to determine the critical water temperature (Tcw), defined as the lowest water temperature a subject can tolerate at rest for 3 h without shivering, of wet-suited subjects during water immersion at different ambient pressures. Nine healthy males wearing neoprene wet suits (5 mm thick) were subjected to immersion to the neck in water at 1, 2, and 2.5 ATA while resting for 3 h. Continuous measurements of esophageal (T(es)) and skin (Tsk) temperatures and heat loss from the skin (Htissue) and wet suits (Hsuit) were recorded. Insulation of the tissue (Itissue), wet suits (Isuit), and overall total (Itotal) were calculated from the temperature gradient and the heat loss. The Tcw increased curvilinearly as the pressure increased, whereas the metabolic heat production during rest and immersion was identical over the range of pressure tested. During the 3rd h of immersion, Tes was identical under all atmospheric pressures; however, Tsk was significantly higher (P less than 0.05) at 2 and 2.5 ATA compared with 1 ATA. A 42 (P less than 0.001) and 50% (P less than 0.001), reduction in Isuit from the 1 ATA value was detected at 2 and 2.5 ATA, respectively. However, overall mean Itissue was maximal and independent of the pressure during immersion at Tcw. The Itotal was also significantly smaller in 2 and 2.5 ATA compared with 1 ATA. The Itissue provided most insulation in the extremities, such as the hand and foot, and the contribution of Isuit in these body parts was relatively small. On the other hand, Itissue of the trunk areas, such as the chest, back, and thigh, was not high compared with the extremities, and Isuit played a major role in the protection of heat drain from these body parts.
本研究旨在确定穿着湿式潜水服的受试者在不同环境压力下进行水浸时的临界水温（Tcw），临界水温定义为受试者在静息状态下能耐受3小时不颤抖的最低水温。九名穿着氯丁橡胶湿式潜水服（5毫米厚）的健康男性在1、2和2.5个绝对大气压（ATA）下颈部浸入水中并静息3小时。连续记录食管温度（T(es)）、皮肤温度（Tsk）以及皮肤（Htissue）和湿式潜水服（Hsuit）的热量损失。根据温度梯度和热量损失计算组织隔热值（Itissue）、湿式潜水服隔热值（Isuit）和总隔热值（Itotal）。随着压力增加，Tcw呈曲线上升，而在测试的压力范围内，静息和浸泡期间的代谢产热相同。在浸泡的第3小时，所有大气压下的食管温度相同；然而，与1个ATA相比，2和2.5个ATA时的皮肤温度显著更高（P<0.05）。在2和2.5个ATA时，分别检测到Isuit相对于1个ATA值降低了42%（P<0.001）和50%（P<0.001）。然而，在Tcw浸泡期间，总体平均Itissue最大且与压力无关。与1个ATA相比，2和2.5个ATA时的Itotal也显著更小。Itissue在诸如手和脚等肢体部位提供了大部分隔热，而Isuit在这些身体部位的贡献相对较小。另一方面，胸部、背部和大腿等躯干部位的Itissue与肢体相比不高，Isuit在保护这些身体部位的热量散失方面起主要作用。
