Natural Light Exposure, Sleep and Depression among Day Workers and Shiftworkers at Arctic and Equatorial Latitudes

• Published in: PLOS ONE
• Main Authors: Marqueze, EC, Vasconcelos, S, Garefelt, J, Skene, DJ, Moreno, CR, Lowden, A
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science 2015
• Subjects: Arctic
• Online Access: http://epubs.surrey.ac.uk/808675/1/Natural%20light%20exposure,%20sleep%20and%20depression%20among%20day%20workers%20and%20shiftworkers%20at%20arctic%20and%20equatorial%20latitudes.pdf; http://epubs.surrey.ac.uk/808675/7/SRI_deposit_agreement.pdf; https://doi.org/10.1371/journal.pone.0122078

OBJECTIVES: This study aimed to investigate the relationship between individual natural light exposure, sleep need, and depression at two latitudes, one extreme with a few hours of light per day during winter, and the other with equal hours of light and darkness throughout the year. METHODS: This cross-sectional study included a sample of Brazilian workers (Equatorial, n = 488 workers) and a Swedish sample (Arctic, n = 1,273). RESULTS: The reported mean total natural light exposure per 4-week cycle differed significantly between the Equatorial and Arctic regions. However, shiftworkers from both sites reported similar hours of natural light exposure. Short light exposure was a predictor for insufficient sleep. CONCLUSION: Reduced exposure to natural light appears to increase the perception of obtaining insufficient sleep. Arctic workers were more prone to develop depression than Equatorial workers.