Morningness-eveningness comparison in adolescents from different countries around the world
Abstract
Very few studies have focused on differences in chronotype around the globe. In this study, morningness-eveningness was measured using the Composite Scale of Morningness and the midpoint of sleep on free days (corrected for sleep debt, MSF(sc)) in adolescents of sixteen German schools abroad, dispersed all over the world, and for comparison pupils attending German schools. There was no influence of duration of residence in the respective locality, and sex differences were weak. Age correlated negatively with morningness. A significant influence of climate zone (temperate, subtropics, tropics) was found, with adolescents in the subtropics being the latest chronotypes, and an interaction of agexclimate zone was identified. Significant associations between chronotype and longitude and latitude were identified within the time zone of central Europe. Adolescents were found to be more morning oriented both toward the East and North. The results indicate that climate, longitude, and latitude contribute to chronotype.
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Country-specific differences in chronotype have been reported by several studies.
“Accordingly, country-specific differences in chronotype have been reported by several studies (46, 56–58).”
From Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health (2019) · cites this paper as [56]
Delays in sleep, circadian preference, and chronotype begin around puberty and reach maximum around age 20 before shifting earlier over the lifespan.
“Delays in sleep, circadian preference, and chronotype begin around puberty and reach their maximum around age 20 before beginning a long, slow shift towards earlier timing over the lifespan (35,36).”
From Impact of Sleep and Circadian Rhythms on Addiction Vulnerability in Adolescents (2018) · cites this paper as [35]
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References 44 · Cited by 197
- Authors
- Randler, C.
- Affiliations
- Leipzig University (DE)
- Corresponding author
- Randler, Christoph
- ORCID
- Randler, Christoph
- Venue
- Chronobiology International
- Publisher
- Informa UK Limited
- Published
- 2008-01
- Volume
- 25
- Issue
- 6
- Pages
- 1017-1028
- ISSN
- 0742-0528 (ISSN-L)
- 1525-6073
- OpenAlex
- W2102475386
- Cited by
- 197
- References
- 44
- Citations by year
- 2026: 10 · 2025: 13 · 2024: 5 · 2023: 14 · 2022: 7 · 2021: 11 · 2020: 10 · 2019: 10 · 2018: 15 · 2017: 10 · 2016: 9 · 2015: 10 · 2014: 16 · 2013: 9 · 2012: 16
- FWCI
- 14.52
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Chronobiology International (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
- Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
- Life Sciences › Neuroscience › Cognitive Neuroscience › Sleep and Wakefulness Research
- Keywords
- chronotype, adolescents, climate zones, latitude, longitude, age differences, sex differences, sleep timing, cross-national comparison, German schools abroad
- MeSH terms
- Adolescent, Age Factors, Biological Clocks, Child, Circadian Rhythm, Climate, Europe, Germany, Humans, International Cooperation, Seasons, Sleep, Time Factors, Wakefulness, Photoperiod
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