Exploring the effects of spectral light exposure on University students' sleep quality: A cross-sectional study

International Centre for Indoor Environment and Energy, Department of Environmental and Resource Engineering, Technical University of Denmark

^* Corresponding author: masak@dtu.dk

Abstract

In developed nations, 2/3 of the population fail to obtain the recommended 7-9 hours of sleep, with large consequences for health and productivity. A potent stimulus in regulating sleep and wake balance is light received at a light-sensitive retinal protein called melanopsin, found in our retinal cells, otherwise known as intrinsically retinal ganglion cells (ipRGCs). Hence, to better understand the effects of bedroom indoor environmental quality IEQ on sleep, we set up a study to objectively explore the impact of spectral light exposure through non-visual pathways on the participants' sleep quality. For one week, University students measured IEQ in their bedrooms while monitoring their spectral light exposure during the day and sleep quality at night. The students were asked to keep the bedroom environment unchanged for the measurement period. Our preliminary results show trends between 7-day accumulative light exposure and length of deep sleep. This trend is not significant, and further in-depth analysis is needed. Among other limitations in the processed data, the diverse and mixed demographic of the sample was not considered. The students' living conditions (single vs. family, accommodation, etc.) varied in this initial analysis.