Psychological and physiological influences of CCTs on young people before sleep

This research studied the psychological and physiological impacts of different lighting conditions on young people before sleep. Young people were recruited as subjects aged from 21 to 25. The experiment had three lighting conditions with the same illuminance at 50lx, and the correlated color temperatures (CCT) are 2700K, 4000K and 6500K. Subjective questionnaire was used to compare the young people's feelings about the light, while physical parameters such as heart rate, blood pressure and electroencephalograph (EEG) signal were recorded under different lighting conditions. The result of the questionnaire showed 2700K was the most relaxing light for sleep. Analysis of the physical parameters showed there's no significant different for heart rate or blood pressure between different color temperatures. Results also showed the reductions of EEG in α frequency band under all three lighting conditions, and the 2700K had the most significant reduction of α wave. Both subjective results and objective results suggested low color temperature would be more suitable for relaxation and sleep.