Sex differences in facial skin temperature when exposed to darkness with and without warning

The changes in skin temperature under anxiety were investigated by noninvasive measurements. The nasal skin temperature of 20 subjects was assessed by thermography. The measurement of the skin temperature by thermistor causes stress in subjects. The primary advantages of a thermography over use of a thermistor are noninvasive and accurate. Each subject was made anxious under the 2 conditions of sudden darkness (Sudden darkness condition) or experienced darkness (Experienced darkness condition). Under former, after a baseline facial skin temperature was established, the room light was suddenly turned off. The subject remained seated in darkness for 2 min. The time-series changes were significant for women, but not for men. For women, skin temperature significantly declined in sudden darkness. Experiments on experienced darkness were performed a week later. After a baseline facial skin temperature was established, the subject was told; "The room light would be turned off from now on, but please remain seated without moving". After the instruction, the room light was turned off. The subject remained seated in darkness for 2 min. The resultant time-series changes in skin temperatures were significant in neither men nor women.