1-17 Effect of Low Relative Humidity on Physiological and Psychological Responses-A Comparison between Old and Young People

The purpose of this study was to investigate the effect of low relative humidity on physiological and psychological responses. In order to investigate the influence of low relative humidity, we measured Saccharin Clearance Time (SCT), Frequency of Blinking, Heart Rate Variability (HRV), blood pressure, hydration state, transepidermal water loss (TEWL), recovery sebum and skin temperature as physiological responses. Also, we asked subjects to judge thermal, dryness and comfort sensation as psychological responses using a rating scale. As the subjects of the experiment, eight non smoking healthy male students (21.7±0.8 yr) and elderly (71.1±4.1 yr) were selected. The pre-room was controlled with an air temperature (Ta) of 25℃ and relative humidity of 50%. The test-room was adjusted with a Ta of 25℃ and relative humidity of 10%, 30% and 50%, respectively. SCT of older age group under the thermal condition with a Ta of 25℃ and relative humidity of 10% was significantly longer than younger age group. And Frequency of Blinking in both older and younger age group was significantly increased under the thermal condition with a Ta of 25℃ and relative humidity of 10% and 30%, respectively. But, there was no significant difference between older and younger age group. Also, there were no significant differences between two groups in hydration state, TEWL and comfort sensation. Younger age group was significantly more sensitive to dryness and thermal sensation than older age group.