Elemental examines the growing research that suggests that bright outdoor lighting negatively affects sleep and moods, and may even increase the risk of disease.
In places across America where artificial outdoor light is brightest at night, teenagers sleep on average 11 minutes less than teens in darker areas, according to a new study, published July 8 in the journal JAMA Psychiatry.
Researchers used satellite data to gauge light levels by census blocks (there are more than 200,000 of them in the United States) and compared that to answers from questionnaires given to 10,123 teens, ages 13 to 18. Teens in the brightest areas went to bed late and slept less, even after researchers accounted for population density. They were also more likely to have anxiety or mood disorders, including meeting the diagnostic criteria for bipolar disorder.