Wyon D P, Andersen I, Lundqvist G R
Scand J Work Environ Health. 1979 Dec;5(4):352-61. doi: 10.5271/sjweh.2646.
Moderate heat stress is believed to affect mental performance by lowering levels of arousal. Conscious effort can counteract this effect. In most experiments, raised temperatures are perceived at the start by subjects and can act as a stimulus to exert conscious effort. In practice, temperatures usually rise slowly and may therefore have a more marked effect. Thirty-six male and 36 female 17-year-old subjects in standard cotton uniforms (0.7 clo) were exposed in groups of four in a climate chamber to rising air-temperature conditions typical of occupied classrooms, in the range 20--29 degrees C. The maximum rate of rise was 4 degrees C/h. Each group performed mental work during three successive periods of 50 min with 10-min breaks between. During each break the air temperature was reduced by 3 degrees C. Sentence comprehension was significantly reduced by intermediate levels of heat stress in the third hour. A multiplication task was performed significantly more slowly in the heat by male subjects, showing a minimum at 28 degrees C. Recognition memory showed a maximum at 26 degrees C, decreasing significantly at temperatures below and above, and an independent measure of degree of certainty in recall showed a maximum at 27 degrees C. These findings are in accordance with the hypothesis of reduced arousal in moderate heat stress in the absence of conscious effort.
一般认为，中度热应激会通过降低觉醒水平来影响心理表现。有意识的努力可以抵消这种影响。在大多数实验中，受试者一开始就能察觉到温度升高，这可以成为促使他们做出有意识努力的一种刺激。在实际情况中，温度通常是缓慢上升的，因此可能会产生更显著的影响。36名17岁男性和36名17岁女性受试者身着标准棉质制服（0.7克罗），每四人一组进入气候舱，暴露于20至29摄氏度的、类似于有人教室的气温上升环境中。最大升温速率为每小时4摄氏度。每组在连续三个50分钟的时间段内进行脑力工作，期间有10分钟的休息时间。每次休息时，气温会降低3摄氏度。在第三个小时，中度热应激水平会显著降低句子理解能力。男性受试者在高温环境下进行乘法运算的速度明显更慢，在28摄氏度时达到最慢。再认记忆在26摄氏度时达到最佳，在低于和高于此温度时显著下降，而一项关于回忆确定性程度的独立测量在27摄氏度时达到最佳。这些发现与在没有有意识努力的情况下，中度热应激会降低觉醒水平的假设相符。
