Latitudinal cline of chronotype

Mario André Leocadio-Miguel*, Fernando Mazzili Louzada, Leandro Lourenção Duarte, Roberta Peixoto Areas, Marilene Alam, Marcelo Ventura Freire, John Fontenele-Araujo, Luiz Menna-Barreto, Mario Pedrazzoli

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)


The rotation of the Earth around its own axis and around the sun determines the characteristics of the light/dark cycle, the most stable and ancient 24 h temporal cue for all organisms. Due to the tilt in the earth's axis in relation to the plane of the earth's orbit around the sun, sunlight reaches the Earth differentially depending on the latitude. The timing of circadian rhythms varies among individuals of a given population and biological and environmental factors underlie this variability. In the present study, we tested the hypothesis that latitude is associated to the regulation of circadian rhythm in humans. We have studied chronotype profiles across latitudinal cline from around 0° to 32° South in Brazil in a sample of 12,884 volunteers living in the same time zone. The analysis of the results revealed that humans are sensitive to the different sunlight signals tied to differences in latitude, resulting in a morning to evening latitudinal cline of chronotypes towards higher latitudes.

Original languageEnglish
Pages (from-to)5437
JournalScientific Reports
Issue number1
Publication statusPublished - 14 Jul 2017
Externally publishedYes

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