Flouris Andreas D, Westwood David A, Cheung Stephen S
School of Health and Human Performance, Dalhousie University, Halifax, Nova Scotia, Canada.
Aviat Space Environ Med. 2007 Jul;78(7):673-9.
Human mental performance is markedly affected by environmental temperature, body temperature, body heat content, and comfort, but the effects of these different factors are not entirely clear. A liquid conditioning garment (LCG) can be used to manipulate these factors independently. We hypothesized that cold exposure (coldEX) has negative effects on vigilance which can be alleviated by increasing body heat content throughout or prior to coldEX.
Subjects (n = 10) were tested for vigilance during a 130-min coldEX to -20 degrees C while warmly clothed; a period of moderate exercise occurred at minutes 64-74. An LCG was used to provide heating either before coldEX (prior heating, PH) or throughout coldEX (heating, H); the control condition involved no heating (NH).
There were significant differences among conditions for rectal temperature (PH: 37.3 +/- 0.26 degrees C, H: 37.0 +/- 0.24 degrees C, NH: 37.05 +/- 0.26 degrees C) and mean skin temperature (PH: 33.85 +/- 1.21 degrees C, H: 35.11 +/- 1.35 degrees C, NH: 32.84 +/- 0.65 degrees C). Reaction time decreased significantly after the 45th minute of coldEX in H and NH. At the same time, signal detection criteria in all conditions demonstrated considerable alterations, indicating bias in favor of 'target-present' responses, which were associated with lower mean skin temperature and thermal comfort vote. PH was more effective than H and NH in preserving reaction time and response consistency. Relative to men, women demonstrated increased heat loss and more deteriorated vigilance and signal detection.
Vigilance deteriorates in cold conditions within 45 min of exposure. Increasing body heat content prior to coldEX is efficacious in preserving vigilance performance during exposures lasting up to 2 h.
人类的心理表现会受到环境温度、体温、身体热量含量和舒适度的显著影响，但这些不同因素的影响并不完全清楚。液体调节服装（LCG）可用于独立操控这些因素。我们假设冷暴露（coldEX）会对警觉性产生负面影响，而在整个冷暴露期间或之前增加身体热量含量可缓解这种影响。
10名受试者在穿着保暖衣物的情况下，接受了130分钟至-20摄氏度的冷暴露测试；在第64至74分钟进行了一段适度运动。使用LCG在冷暴露前（预加热，PH）或整个冷暴露期间（加热，H）提供加热；对照条件为不加热（NH）。
直肠温度（PH：37.3±0.26摄氏度，H：37.0±0.24摄氏度，NH：37.05±0.26摄氏度）和平均皮肤温度（PH：33.85±1.21摄氏度，H：35.11±1.35摄氏度，NH：32.84±0.65摄氏度）在各条件之间存在显著差异。在H和NH组中，冷暴露第45分钟后反应时间显著缩短。同时，所有条件下的信号检测标准都出现了相当大的变化，表明倾向于“目标存在”反应的偏差，这与较低的平均皮肤温度和热舒适度评分相关。PH在保持反应时间和反应一致性方面比H和NH更有效。相对于男性，女性表现出更多的热量损失以及更差的警觉性和信号检测能力。
暴露于寒冷环境中45分钟内警觉性会下降。在冷暴露前增加身体热量含量对于在长达2小时的暴露期间保持警觉性表现是有效的。
