Effects of artificial light at night and light pollution on human circadian rhythms

Artificial light is a tangible manifestation of economic and social development, as well as a response to certain needs, especially comfort and civil and road safety. However, this use has been so associated with technological progress that its invasion of daily life has been almost imperceptible. With the recent increase in night lighting (11 million light points in 2016 according to the French Agency for the Environment and Energy Management) and the production of new lamp technologies (in particular light-emitting diodes or LEDs), societal concerns have emerged and are growing. These concerns include light pollution and the impact of blue light on human health and the environment. The scientific community has also taken up the subject, publishing in recent years a large and ever-increasing number of articles on the effects of artificial light at night on fauna and flora as well as on human health. In this review, we propose a synthesis of knowledge on human health effects of light based on scientific reports and an update of recent scientific production. This review updates knowledge of the chronobiological effects of light at night, particularly blue light. We also briefly describe the potential beneficial effects of light on well-being.