Changes in facial moisture distribution and feelings of moisture/dryness among various environmental temperatures and humidities in summer and winter

• Published in: Skin research and technology Vol. 26; no. 6; pp. 937 - 948
• Main Authors: Egawa, Mariko, Koizumi, Koyo, Hirao, Tetsuji
• Format: Journal Article
• Language: English
• Published: Copenhagen John Wiley & Sons, Inc 01.11.2020
• Subjects: Environmental conditions; High temperature; Humidity; imaging; Infrared imaging; Low temperature; Moisture; near‐infrared; Sensory evaluation; sensory stimulation sensitivity; Skin; Summer; Temperature; water; Winter
• ISSN: 0909-752X; 1600-0846; 1600-0846
• DOI: 10.1111/srt.12898

Background As environmental conditions vary depending on area of residence, consideration of environmental temperature and humidity conditions is crucial for detection of actual skin conditions in daily life. In this study, we determined changes in facial moisture and sensory evaluation distributions in various environmental temperature and humidity conditions. Materials and Methods An original near‐infrared (NIR) imaging system was used to obtain moisture distributions. Sensory evaluations of feelings of moisture/dryness were graded, and changes were compared among 10 healthy Japanese female subjects in four different environmental temperature and humidity conditions (28°C, 60% RH; 28°C, 20% RH; 15°C, 60% RH; 15°C, 20% RH) in summer and winter. Results Skin moisture was lower at high temperatures and higher at low temperatures. Feelings of dryness on bare skin were high in low humidity. Sensitivity of feelings of moisture and dryness was high around the center of the cheekbones between side of the eyes and the mouth, but the same was not true of the moisture distribution. Moisture level was lower in winter at high temperatures, especially under the eyes near the side of the nose ridge, while the sense of dryness was not strong. These divergences between sensory evaluation and moisture level indicate the presence of a “hidden dry situation.” Conclusion Changes in moisture level and sensory evaluation scores in facial skin varied among environmental conditions, which differed between summer and winter, even under the same environmental temperature and humidity.