The Effect Of Light On Human Alertness,Performance And Circadian Rhythm

With the rapid growth of technowledge,people finally have the ability to control light accurately.The concept of health lighting is becoming more and more popular.However,due to the limitations of current biological research,most scholars are still using CCT and illuminance,which used to be applied to judge the visual effect of light on the human body.At home and abroad,there is no convincing measurement standard of healthy lighting.The study carried out experiments to explore the relationship between past indicators and the proposed new indicators to identify which of them were better and more comprehensive,and if the past indicators can be replaced by the new indicators.In the study of how light with different CCT can influence human sleep and circadian rhythm,two light conditions with same irradiance,CS and Ez but different CS were used.Ten undergraduates joined the experiment as participants.Outcome measures that used were questonnaires,CFFT and hormone concentrations in saliva samples.The results showed that CCT can have effect on human sleep and circadian rhythm even when irradiance,CS and Ez are the same.Participants had worse sleep and more interrupted cirdian rhythm under light that had higher CCT.Also,partipants had more severe eye discomfort under high-CCT light.In the study of how light affect human alertness and performance,three light conditions were used and the outcome measures were questonnaires,electroencephalogram,CFFT,task performance and cortisol concentration in saliva samples.The partiicpants were 18 adults with the mean age of 22.Results showed that while quantifying the influence of light on human alertness and performance,irradiance can be replaced by Ez.Also,results of indirect comparison suggested that Ez is slightly better than CS.This experiment assessed the accuracy of CS,Ez and irradiance and provided database for the criterion of the non-visual effect of light that CIE wants to lay down.