Psychological and physiological effects of green light on humans

Abstract

Physiological and psychological eects of illumination with dierent colored lights on humans were investigated in order to improve lighting conditions in medical treatment environments. Women n12 participated in an experiment in which they were exposed to illumination using 900 lx and 200 lx white uorescent lamps, and a 200 lx lamp covered with a green cellophane transparent lm. Physiological variables such as heart rate, HF values , LF/HF ratio, and Chromogranin A in saliva, as well as psychological variables such as subjective feelings of relaxation were measured using the Visual Analogue Scale test and the short version of the Japanese Prole of Mood. Participants subjected to stress conditions created by using the Uchida-Kraepelin test under white uores-cent lighting and then tested aer 15 min of rest following stress in all three lighting conditions. Results indicated that there was a suppression of sympathetic activity, an increase in parasympathetic activity, as well as an improvement in physiological responses when using the 200 lx green light. ere was also an improvement in psychological reactions and the feeling of relaxation, as well as a reduction in anxiety-tension, fatigue and confusion .