A Field Diary Study on the Effects of Daytime Light Exposure Patterns on Sleep and Psychological Function in University Students
DENG Zikan
HE Meiheng
BAI Hongxia
LI Siyu
RU Taotao
Abstract：Day-night light exposure levels are closely related to individual physical and mental health.Due to their relatively free behavior patterns,university students show large individual differences in the level and timing of light exposure.In this study,60 university students were recruited from South China Normal University.Using the ecological momentary assessment(EMA)method,continuous light exposure data were collected for one week,while psychological alertness,emotional states at different daytime periods,and nighttime sleep were also measured.The aim was to examine the impact of different daytime light exposure patterns on students' sleep and psychological functioning.Based on daytime light exposure measurements,two typical patterns emerged:the"M-shaped"type and the"flat-line"type.Statistical analysis showed that the M-shaped type had lower average light intensity during both daytime and nighttime compared to the flat-line type,and in both patterns,participants' daytime light exposure remained at a relatively low level.Moreover,the M-shaped pattern displayed larger fluctuations in light exposure,with lower exposure around 8:00 a.m.and 2:00 p.m.,and higher levels at other times of day.Under this pattern,participants tended to have an earlier circadian rhythm.In contrast,the flat-line pattern maintained a relatively stable level of light exposure throughout the day,and participants under this pattern reported higher sustained alertness,greater work efficiency,and fewer negative emotions,though with a delayed circadian phase.
Keywords：lightsleepalertnessmoodcircadian rhythm
Publication Date：2025-10-31
Online Publishing Date：2025-11-27(First online date of this platform, not the publication date of the document)
Pages：8( 94-101 )