title: Ancestral sleep.
abstract: While we do not yet understand all the functions of sleep, its critical role for normal physiology and behaviour is evident. Its amount and temporal pattern depend on species and condition. Humans sleep about a third of the day with the longest, consolidated episode during the night. The change in lifestyle from hunter-gatherers via agricultural communities to densely populated industrialized centres has certainly affected sleep, and a major concern in the medical community is the impact of insufficient sleep on health [1,2]. One of the causal mechanisms leading to insufficient sleep is altered exposure to the natural light-dark cycle. This includes the wide availability of electric light, attenuated exposure to daylight within buildings, and evening use of light-emitting devices, all of which decrease the strength of natural light-dark signals that entrain circadian systems [3].
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195-1800, USA.
authors.forename: Horacio O
authors.initials: HO
authors.lastname: de la Iglesia
authors.affiliation: School of Public Health, University of São Paulo, 01246-904, Brazil; Stress Research Institute, Stockholm University, 106 91, Sweden.
authors.forename: Claudia
authors.initials: C
authors.lastname: Moreno
authors.affiliation: Stress Research Institute, Stockholm University, 106 91, Sweden.
authors.forename: Arne
authors.initials: A
authors.lastname: Lowden
authors.affiliation: Department of Physiology, Federal University of Paraná, 80610-280, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Louzada
authors.affiliation: School of Public Health, University of São Paulo, 01246-904, Brazil; Catholic University of Santos,11.015-002, Brazil.
authors.forename: Elaine
authors.initials: E
authors.lastname: Marqueze
authors.affiliation: Programa de Saúde Coletiva (UFRGS), Porto Alegre, RS, 90460-150, Brazil.
authors.forename: Rosa
authors.initials: R
authors.lastname: Levandovski
authors.affiliation: Departamento de Psiquiatria e Medicina Legal (UFRGS), Porto Alegre, RS, 90035-903, Brazil; Ludwig-Maximilian-University, Munich, 80336, Germany.
authors.forename: Luisa K
authors.initials: LK
authors.lastname: Pilz
authors.affiliation: Department of Anthropology, Yale University, New Haven, CT 06511, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Valeggia
authors.affiliation: Department of Anthropology, Yale University, New Haven, CT 06511, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fernandez-Duque
authors.affiliation: Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, 1876, Argentina.
authors.forename: Diego A
authors.initials: DA
authors.lastname: Golombek
authors.affiliation: Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115-1104, USA.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Czeisler
authors.affiliation: Faculty of Health & Medical Sciences, University of Surrey, GU2 7XH, UK.
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Skene
authors.affiliation: Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115-1104, USA.
authors.forename: Jeanne F
authors.initials: JF
authors.lastname: Duffy
authors.affiliation: Ludwig-Maximilian-University, Munich, 80336, Germany. Electronic address: roenneberg@lmu.de.
authors.forename: Till
authors.initials: T
authors.lastname: Roenneberg
mesh_terms: D002940:Circadian Rhythm; D006801:Humans; D008027:Light; D008550:Melatonin; D017440:Photoperiod; D012890:Sleep; D020178:Sleep Disorders, Circadian Rhythm
chemical_list: D008550:Melatonin