Abstract: The present review draws together wide-ranging studies performed over the last decades that catalogue the effects of artificial-light-at-night (ALAN) upon living species and their environment. We provide an overview of the tremendous variety of light-detection strategies which have evolved in living organisms – unicellular, plants and animals, covering chloroplasts (plants), and the plethora of ocular and extra-ocular organs (animals). We describe the visual pigments which permit photo-detection, paying attention to their spectral characteristics, which extend from the ultraviolet into infrared. We discuss how organisms use light information in a way crucial for their development, growth and survival: phototropism, phototaxis, photoperiodism, and synchronization of circadian clocks. These aspects are treated in depth, as their perturbation underlies much of the disruptive effects of ALAN. The review goes into detail on circadian networks in living organisms, since these fundamental features are of critical importance in regulating the interface between environment and body. Especially, hormonal synthesis and secretion are often under circadian and circannual control, hence perturbation of the clock will lead to hormonal imbalance. The review addresses how the ubiquitous introduction of light-emitting diode technology may exacerbate, or in some cases reduce, the generalized ever-increasing light pollution. Numerous examples are given of how widespread exposure to ALAN is perturbing many aspects of plant and animal behaviour and survival: foraging, orientation, migration, seasonal reproduction, colonization and more. We examine the potential problems at the level of individual species and populations and extend the debate to the consequences for ecosystems. We stress, through a few examples, the synergistic harmful effects resulting from the impacts of ALAN combined with other anthropogenic pressures, which often impact the neuroendocrine loops in vertebrates. The article concludes by debating how these anthropogenic changes could be mitigated by more reasonable use of available technology – for example by restricting illumination to more essential areas and hours, directing lighting to avoid wasteful radiation and selecting spectral emissions, to reduce impact on circadian clocks. We end by discussing how society should take into account the potentially major consequences that ALAN has on the natural world and the repercussions for ongoing human health and welfare.
Abstract: Shiftwork, including work that takes place at night (nightshift) and/or rotates between day and nightshifts, plays an important role in our society, but is associated with decreased health, including reproductive dysfunction. One key factor in shiftwork, exposure to light at night, has been identified as a likely contributor to the underlying health risks associated with shiftwork. Light at night disrupts the behavioral and molecular circadian timekeeping system, which is important for coordinated timing of physiological processes, causing mistimed hormone release and impaired physiological functions. This review focuses on the impact of shiftwork on reproductive function and pregnancy in women and laboratory rodents and potential underlying molecular mechanisms. We summarize the negative impact of shiftwork on female fertility and compare these findings to studies in rodent models of light shifts. Light-shift rodent models recapitulate several aspects of reproductive dysfunction found in shift workers, and their comparison with human studies can enable a deeper understanding of physiological and hormonal responses to light shifts and the underlying molecular mechanisms that may lead to reproductive disruption in human shift workers. The contributions of human and rodent studies are essential to identify the origins of impaired fertility in women employed in shiftwork.
Keywords: Review; Human Health; Animals; birth; circadian disruption; estrous cycles; fertility; infertility; menstrual cycles; pregnancy; rodent; shiftwork; women
Abstract: Visible light is all around us, from sunlight to street lighting and automobile headlights to the backlight on a smartphone and in nearly every indoor space. Humans are so accustomed to working and living in artificial light that many of us have not stopped to consider the implications. Most OSH professionals’ experience with light and artificial lighting is likely limited to assessing whether sufficient light exists for people to see where they are going or carry out a task, or whether a light is too bright. This article aims to provide a current review of lighting for OSH professionals. Such a review is timely due to emerging issues including energy efficiency, human health impacts (e.g., blue light hazard, circadian rhythm disruption, fatigue), human performance (e.g., visual performance, visual comfort) and environmental impacts (e.g., light pollution).
Keywords: Review; Human Health; Lighting; Safety
Abstract: Sleep in the ICU is poor and improving sleep proves to be challenging. However, clinical trials on the use of pharmacological and non-pharmacological interventions to improve sleep in the ICU are scarce. The few clinical trials that have been performed are hampered by difficulty in obtaining reliable objective sleep measurements in the ICU environment. Therefore, firm evidence on the effect of all commonly used interventions is limited. Strategies to decrease noise and light exposure seem promising, since pilot studies and small clinical trials suggest that implementation is feasible and most interventions are low-cost. Standardisation of sleep-promoting protocols might lead to a possibility of performing multicentre trials that can provide much needed evidence on the efficacy of non-pharmacological interventions to improve sleep in the ICU. Although many different medications are used to improve sleep in the ICU, there is insufficient evidence in the literature to support the use of any of them to effectively improve sleep. The use of benzodiazepines is not recommended based on the lack of evidence for their efficacy and the association with increased risk of delirium. Emphasis on non-pharmacological sleep-promoting measures before prescribing medication is warranted, as it is currently not clear to what extent prescribing sleep-promoting medications is actually beneficial to ICU patients. Clinical trials on existing pharmacological options and expanding treatment options by considering sodium oxybate or suvorexant are logical future directions to improve the treatment of sleep problems in the ICU.
Keywords: Human Health; Review
Abstract: Context
Artificial light at night (ALAN) provides an array of important benefits but might also adversely affect humans and other living organisms. Yet, the existing reviews of accumulated knowledge about the multifaceted effects associated with exposure to ALAN focus on distinct ecosystem components. As a result, our understanding of potential system-wide impacts of ALAN exposure is insufficient.
Objectives
This paper attempts to bridge this knowledge gap by reviewing a wide range of studies, with a particular focus on identifying the impacts of ALAN exposure that are common to different species.
Methods
The survey is conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and covers peer-reviewed articles published from 2000 to 2019.
Results
Seventy-four eligible articles, out of 1223 initially identified, were selected and synthesized. 20% of them focus on humans, while the rest explore other living organisms, such as vertebrates, avian species, arthropods, aquatic organisms, and vegetation. The review demonstrates that similar adverse effects of ALAN exposure, ranging from sleep disturbance, depression, weight gain, eating and movement disorders, to elevated risk of cancer, are manifested across different components of the ecosystem, and therefore entail wider and more complex risks to its stability and integrity.
Conclusion
To reduce ecosystem risks, associated with constantly increasing ALAN levels, illumination policies should be based on directional and reduced nighttime lighting, which can help to avoid unnecessary exposures. The study highlights knowledge gaps that warrant further research attention.
Artificial light at night (ALAN) provides an array of important benefits but might also adversely affect humans and other living organisms. Yet, the existing reviews of accumulated knowledge about the multifaceted effects associated with exposure to ALAN focus on distinct ecosystem components. As a result, our understanding of potential system-wide impacts of ALAN exposure is insufficient.
Objectives
This paper attempts to bridge this knowledge gap by reviewing a wide range of studies, with a particular focus on identifying the impacts of ALAN exposure that are common to different species.
Methods
The survey is conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and covers peer-reviewed articles published from 2000 to 2019.
Results
Seventy-four eligible articles, out of 1223 initially identified, were selected and synthesized. 20% of them focus on humans, while the rest explore other living organisms, such as vertebrates, avian species, arthropods, aquatic organisms, and vegetation. The review demonstrates that similar adverse effects of ALAN exposure, ranging from sleep disturbance, depression, weight gain, eating and movement disorders, to elevated risk of cancer, are manifested across different components of the ecosystem, and therefore entail wider and more complex risks to its stability and integrity.
Conclusion
To reduce ecosystem risks, associated with constantly increasing ALAN levels, illumination policies should be based on directional and reduced nighttime lighting, which can help to avoid unnecessary exposures. The study highlights knowledge gaps that warrant further research attention.
Keywords: Human Health; Ecology; Review