Cleary-Gaffney, Michael (2022) The dark side of artificial light: Examining the perception and intensity of light at night in the sleeping environment and its association with sleep, circadian rhythmicity, attention bias and psychological health. PhD thesis, National University of Ireland Maynooth.

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Abstract

Due to technological advances and affordability exposure to Light-at-night (LAN) is now ubiquitous both inside our private dwellings and our external environment. While LAN provides us with the agency to extend our biological day into the evening this may lead to adverse consequences for circadian rhythmicity and the timing of sleep. Additionally, LAN exposure may lead to adverse health consequences either indirectly via circadian disruption or directly impacting on health. Technological advances in both the accessibility and quality of lighting have outpaced our understanding of the impacts of LAN on sleep and health. The association between home-setting LAN with sleep and psychological health is unclear. This study specifically examines LAN exposure in the sleeping environment and its association with sleep and psychological health. Using both cross-sectional and ecological study designs this research seeks to examine what are the perceived sources and intensity of LAN which individuals are exposed to in their sleeping environment. What is the association between these sources with sleep timing, circadian misalignment and psychological health. Our research indicates that LAN is perceived from a variety of sources in the sleeping environment. Those that perceive LAN are more likely to report that these sources are disruptive to their sleep. We report for the first time that the subjective perception of external LAN is associated with both poor sleep quality and psychological health. Due to limitations of satellite image data we employed a novel approach to objectively measure external light pollution individualized to the dwelling of the participant. We report no association between the subjective perception of LAN and objective measurements. This research examined whether the association between the subjective perception of LAN and poor sleep quality despite equally comparable levels of outdoor LAN to those that do not perceive it was due to an attention bias towards sleep related information. Our results report no significant effect of the perception of LAN in the sleeping environment with attention bias towards sleep-related word stimuli or towards images depicting LAN sleep environments. Finally, this study examined whether objectively measured LAN intensity measured from the window and bedside was associated with alterations to sleep timing, sleep quality and rest-activity patterns derived from actigraphy. Our results report that window LAN intensity is associated with delayed timing of L5 and sleep onset. However, bedside LAN is not associated with any alterations to our outcome variables. Our research also highlights that increased LAN intensity is not associated variance in sleep timing, quality, daily mood or daily subjective sleepiness.

Item Type:	Thesis (PhD)
Keywords:	dark side; artificial light; perception and intensity; light at night; sleeping environment; sleep; circadian rhythmicity; attention bias; psychological health;
Academic Unit:	Faculty of Science and Engineering > Psychology
Item ID:	16543
Depositing User:	IR eTheses
Date Deposited:	20 Sep 2022 13:24
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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