title: Sleep patterns in Amazon rubber tappers with and without electric light at home.
abstract: Today's modern society is exposed to artificial electric lighting in addition to the natural light-dark cycle. Studies assessing the impact of electric light exposure on sleep and its relation to work hours are rare due to the ubiquitous presence of electricity. Here we report a unique study conducted in two phases in a homogenous group of rubber tappers living and working in a remote area of the Amazon forest, comparing those living without electric light (n = 243 in first phase; n = 25 in second phase) to those with electric light at home (n = 97 in first phase; n = 17 in second phase). Questionnaire data (Phase 1) revealed that rubber tappers with availability of electric light had significantly shorter sleep on work days (30 min/day less) than those without electric light. Analysis of the data from the Phase 2 sample showed a significant delay in the timing of melatonin onset in workers with electric light compared to those without electric light (p < 0.01). Electric lighting delayed sleep onset and reduced sleep duration during the work week and appears to interfere with alignment of the circadian timing system to the natural light/dark cycle.
authors.affiliation: School of Public Health, University of São Paulo, Brazil.|School of Public Health, University of São Paulo, Brazil.
authors.forename: C R C
authors.initials: CR
authors.lastname: Moreno
authors.affiliation: School of Public Health, University of São Paulo, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Vasconcelos
authors.affiliation: School of Public Health, University of São Paulo, Brazil.|Catholic University of Santos, Brazil.
authors.forename: E C
authors.initials: EC
authors.lastname: Marqueze
authors.affiliation: Stress Research Institute, Stockholm University, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lowden
authors.affiliation: Faculty of Health &Medical Sciences, University of Surrey, UK.
authors.forename: B
authors.initials: B
authors.lastname: Middleton
authors.affiliation: School of Public Health, University of São Paulo, Brazil.
authors.forename: F M
authors.initials: FM
authors.lastname: Fischer
authors.affiliation: Department of Physiology, Federal University of Paraná, Brazil.
authors.forename: F M
authors.initials: FM
authors.lastname: Louzada
authors.affiliation: Faculty of Health &Medical Sciences, University of Surrey, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Skene
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D003710:Demography; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008019:Life Style; D008029:Lighting; D008297:Male; D008550:Melatonin / Q000378:metabolism; D008875:Middle Aged; D017440:Photoperiod; D012463:Saliva / Q000378:metabolism; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires
chemical_list: D008550:Melatonin