Week 1: Initial literature review

Welcome to the second post for this project. In the previous post, I gave a general introduction to the issue of light pollution and explained the goals of this project. Light pollution is the excessive presence of artificial light in the night sky. I will understand the relationship that light pollution has with sleep quality, if there is any. This week, I studied a few scientific papers that discussed both the relationship sleep has with health and the effects that exposure to artificial light has on sleep and health. In this post, I will explain my analysis of these studies and will also describe my future direction for the weeks to come. 

“Factors associated with short and long sleep” by Christopher A Magee, Donald C Iverson, and Peter Caputi describes a study of 49,405 Australian adults. The study aimed to identify factors associated with short sleep and long sleep, and the researchers found that short sleep was associated with long working hours and obesity while long sleep tended to be associated with low physical activity levels and pregnancy. Essentially, health issues or abnormal circumstances have been shown to be correlated with unhealthy sleep behaviors.

I will now talk about a paper that discusses the effects of artificial light on organisms’ sleep and health. “Hormonally mediated effects of artificial light at night on behavior and fitness: linking endocrine mechanisms with function” by Jenny Q. Quyang, Scott Davies, and Davide Dominoni discusses a study regarding the effects of ALAN (Artificial Light At Night) on biological functions. The paper talks about the functions of the pineal, reproductive, adrenal, and thyroid axes and how organisms’ exposure to ALAN interrupts the functions of these endocrine axes. Exposure to the artificial light suppresses melatonin, resulting in sleep problems and health issues. It has also been shown to interrupt reproductive cycles in the organisms. 

I will finally briefly discuss “Impacts of streetlights on sleep in urban birds” by Anne E. Aulsebrook, which is a work consisting of 6 chapters to explain the impact that exposure to artificial light had on the sleep of birds. The first chapter discusses how artificial light affects wildlife reproduction and an organism’s natural life cycle. Artificial light exposure has also been shown to interrupt the timing of seasonal reproduction. The second chapter explores the importance of sleep and the methodology of how scientists study sleep behaviors in animals. The chapter discusses how animals are to be studied in natural environments and should be studied carefully under the knowledge that animals may appear to be asleep when they may actually be awake. The third chapter introduces humans and discusses how both humans and wildlife can suffer from ALAN. Artificial light at night can disrupt sleep patterns, and the chapter goes on to describe health implications caused by these disruptions. The fourth chapter explores a study done specifically on pigeons.  Exposure to ALAN reduced the amount of REM and non-REM sleep that the pigeons had, and these effects lasted for over a day after the initial exposure to this artificial light. The fifth chapter’s study is similar to the fourth chapter. However, this chapter discusses the exposure of artificial light via streetlights on the sleep of black swans. The study found that the streetlights reduced the amount of sleep the swans got at night. The sixth chapter essentially recaps the findings and information that were provided throughout the discussed studies, in addition to also providing a future outlook for research in regards to artificial light exposure and its effects on sleep. 

From reading about these studies, I have learned about what really defines a healthy amount of sleep and the relationship that sleep has with several biological functions. I have also learned the impact that exposure to ALAN has on sleep quality in both humans and wildlife. For the next couple of weeks, I will be continuing to expand my knowledge in this field by reading more scientific literature and publications that delve into relevant research and their findings. I will also begin constructing the survey and refining the methodology that will be used to collect and analyze data from human subjects in areas of varying levels of light pollution. Thank you for reading this post.