Meijo University, Faculty of Science and Technology, Department of Environmental Science and Technology, Shiogamaguchi 1-501, Tenpaku-ku, 468-8502, Nagoya, Aichi Prefecture, Japan.
J Therm Biol. 2021 Apr;97:102870. doi: 10.1016/j.jtherbio.2021.102870. Epub 2021 Mar 6.
Diurnal changes in physiological and behavioral responses to constant relative humidity (RH) were investigated in summer to validate a hypothesis that thermal sensation responses (TSR) vary with the diurnal cycle while maintained at stable RH's of 60, 70, or 80%. Seven lightly clothed male subjects were exposed to one of three RH while air temperature (T) was held at 28 °C from 9:00-18:30. Mean skin temperature (T‾) and tympanic temperature (T) were monitored at 2-min intervals throughout the experimental period. Cutaneous warm and cool sensation thresholds and stratum corneum water content (SCWC) on the anterior forearm, posterior forearm, and anterior thigh, finger blood flow rate (SBF) were measured by a thermal stimulator controlled by a Peltier element (Intercross-230; Intercross, Co., Tokyo, Japan), a water content of stratum corneum monitor (Corneometer CM825 & MPA 5; Integral Co., Tokyo, Japan), and a laser flowmeter (ALF21; Advance Co., Tokyo, Japan), accordingly at the end of three periods: 9:30-10:30, 13:30-14:30, and 17:30-18:30. The TSR and the thermal comfort response were also recorded using subjective scales of thermal sensation and comfort thresholds at the end of three periods. The T and mean skin temperature (T‾) remained unchanged during the day under all RH conditions. Temperature difference between warm and cold sensation thresholds and SBF decreased slightly towards the evening under all RH conditions whereas SCWC increased from the morning to the evening at 60% and 80% RH. Behaviorally, the subjects responded more than "slightly warm" at 70%, and 80% RH, and then the TSR changed significantly (p < 0.05) to less than "slightly warm" in the evening, although T̅ remained unchanged at 34.0 °C. The results from the previous study in winter was reconfirmed, and the data verify the hypothesis that TSR changes diurnally even though subjects are exposed to a constant and high RH's and stable T. It was confirmed in summertime as previously shown in wintertime that the combined reduction in SBF to increases SCWC when exposed to high RH explains the altered TSR although T are unchanged.
研究了夏季恒 RH（相对湿度）下生理和行为反应的日变化，以验证一个假设，即热感觉响应（TSR）随日周期变化，同时保持在 60、70 或 80%的稳定 RH 下。7 名穿着轻便的男性受试者在 9:00-18:30 期间暴露于三种 RH 中的一种，空气温度（T）保持在 28°C。整个实验期间，每隔 2 分钟监测平均皮肤温度（T‾）和鼓膜温度（T）。通过由珀耳帖元件（Intercross-230；Intercross，Co.，Tokyo，Japan）控制的热刺激器测量前臂前侧、前臂后侧和大腿前侧的皮肤温暖和凉爽感觉阈值以及角质层水分含量（SCWC），使用皮肤角质层水分含量监测仪（Corneometer CM825 和 MPA 5；Integral Co.，Tokyo，Japan）和激光流量计（ALF21；Advance Co.，Tokyo，Japan）测量手指血流率（SBF），相应地在三个时间段结束时：9:30-10:30、13:30-14:30 和 17:30-18:30。在三个时间段结束时，还使用热感觉和舒适阈值的主观量表记录 TSR 和热舒适反应。在所有 RH 条件下，T 和平均皮肤温度（T‾）在白天保持不变。在所有 RH 条件下，温暖和寒冷感觉阈值之间的温差和 SBF 略微下降，而 SCWC 从早上到晚上在 60%和 80% RH 下增加。行为上，受试者在 70%和 80% RH 下的反应超过“略热”，然后 TSR 在晚上显著变化（p<0.05）至“略不热”，尽管 T̅ 在 34.0°C 时保持不变。先前冬季研究的结果得到了再次确认，数据验证了即使在高 RH 和稳定 T 下，TSR 也会随日周期变化的假设。在夏季，如冬季所示，当暴露于高 RH 时，SBF 的综合减少导致 SCWC 增加，这解释了改变的 TSR，尽管 T 保持不变。
