Abandoning daylight saving time in Europe raises the topical issue of proper setting of yearlong social time, which needs mapping of various socio-demographic factors, including chronotype, in specific geographic regions. This study represents the first detailed large scale chronotyping in the Czech Republic based on data collected in the complex panel socio-demographic survey in households (total 8760 respondents) and the socio-physiological survey, in which chronotyped participants also provided blood samples (n = 1107). Chronotype assessment based on sleep phase (MCTQ questions and/or time-use diary) correlated with a self-assessed interval of best alertness. The mean chronotype of the Czech population defined as mid sleep phase (MSFsc) was 3.13 ± 0.02 h. Chronotype exhibited significant east-to-westward, north-to-southward, and settlement size-dependent gradients and was associated with age, sex, partnership, and time spent outdoors as previously demonstrated. Moreover, for subjects younger than 40 years, childcare was highly associated with earlier chronotype, while dog care was associated with later chronotype. Body mass index correlated with later chronotype in women whose extreme chronotype was also associated with lower plasma levels of protective HDL cholesterol. Based on the chronotype prevalence the results favour yearlong Standard Time as the best choice for this geographic region.

Institute for Clinical and Experimental Medicine Prague Czech Republic

Institute of Physiology the Czech Academy of Sciences Prague Czech Republic

Institute of Sociology the Czech Academy of Sciences Prague Czech Republic

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Aschoff J. Circadian Rhythms in Man. Science. 1965;148:1427–1432. doi: 10.1126/science.148.3676.1427. PubMed DOI

Daan S, Pittendrigh CS. Functional-Analysis of Circadian Pacemakers in Nocturnal Rodents .2. Variability of Phase Response Curves. Journal of Comparative Physiology. 1976;106:253–266. doi: 10.1007/Bf01417857. DOI

Duffy JF, Wright KP., Jr. Entrainment of the human circadian system by light. J. Biol. Rhythms. 2005;20:326–338. doi: 10.1177/0748730405277983. PubMed DOI

Horne JA, Ostberg O. Individual differences in human circadian rhythms. Biol. Psychol. 1977;5:179–190. doi: 10.1016/0301-0511(77)90001-1. PubMed DOI

Samson David R., Crittenden Alyssa N., Mabulla Ibrahim A., Mabulla Audax Z. P., Nunn Charles L. Chronotype variation drives night-time sentinel-like behaviour in hunter–gatherers. Proceedings of the Royal Society B: Biological Sciences. 2017;284(1858):20170967. doi: 10.1098/rspb.2017.0967. PubMed DOI PMC

Refinetti R, Earle G, Kenagy GJ. Exploring determinants of behavioral chronotype in a diurnal-rodent model of human physiology. Physiol. Behav. 2019;199:146–153. doi: 10.1016/j.physbeh.2018.11.019. PubMed DOI

Sladek M, Polidarova L, Novakova M, Parkanova D, Sumova A. Early chronotype and tissue-specific alterations of circadian clock function in spontaneously hypertensive rats. PLoS One. 2012;7:e46951. doi: 10.1371/journal.pone.0046951. PubMed DOI PMC

Roenneberg, Pilz, Zerbini, Winnebeck Chronotype and Social Jetlag: A (Self-) Critical Review. Biology. 2019;8(3):54. doi: 10.3390/biology8030054. PubMed DOI PMC

Roenneberg T, et al. Epidemiology of the human circadian clock. Sleep Med. Rev. 2007;11:429–438. doi: 10.1016/j.smrv.2007.07.005. PubMed DOI

Czeisler CA, et al. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science. 1999;284:2177–2181. doi: 10.1126/science.284.5423.2177. PubMed DOI

Brown SA, et al. The period length of fibroblast circadian gene expression varies widely among human individuals. PLoS Biol. 2005;3:e338. doi: 10.1371/journal.pbio.0030338. PubMed DOI PMC

Brown SA, et al. Molecular insights into human daily behavior. Proc. Natl. Acad. Sci. USA. 2008;105:1602–1607. doi: 10.1073/pnas.0707772105. PubMed DOI PMC

Duffy JF, Rimmer DW, Czeisler CA. Association of intrinsic circadian period with morningness-eveningness, usual wake time, and circadian phase. Behav. Neurosci. 2001;115:895–899. doi: 10.1037//0735-7044.115.4.895. PubMed DOI

Emens JS, et al. Phase angle of entrainment in morning- and evening-types under naturalistic conditions. Chronobiol. Int. 2009;26:474–493. doi: 10.1080/07420520902821077. PubMed DOI PMC

Roenneberg T, Wirz-Justice A, Merrow M. Life between clocks: daily temporal patterns of human chronotypes. J. Biol. Rhythms. 2003;18:80–90. doi: 10.1177/0748730402239679. PubMed DOI

Jones SE, et al. Genome-Wide Association Analyses in 128,266 Individuals Identifies New Morningness and Sleep Duration Loci. PLoS Genet. 2016;12:e1006125. doi: 10.1371/journal.pgen.1006125. PubMed DOI PMC

Toh KL, et al. An hPer2 phosphorylation site mutation in familial advanced sleep phase syndrome. Science. 2001;291:1040–1043. doi: 10.1126/science.1057499. PubMed DOI

Archer SN, et al. Polymorphism in the PER3 promoter associates with diurnal preference and delayed sleep phase disorder. Sleep. 2010;33:695–701. doi: 10.1093/sleep/33.5.695. PubMed DOI PMC

von Schantz M. Natural Variation in Human Clocks. Adv. Genet. 2017;99:73–96. doi: 10.1016/bs.adgen.2017.09.003. PubMed DOI

Barclay NL, Gregory AM. Quantitative genetic research on sleep: a review of normal sleep, sleep disturbances and associated emotional, behavioural, and health-related difficulties. Sleep Med. Rev. 2013;17:29–40. doi: 10.1016/j.smrv.2012.01.008. PubMed DOI

Kalmbach, D. A. et al. Genetic Basis of Chronotype in Humans: Insights From Three Landmark GWAS. Sleep40, 10.1093/sleep/zsw048 (2017). PubMed PMC

Roenneberg T, et al. A marker for the end of adolescence. Curr. Biol. 2004;14:R1038–1039. doi: 10.1016/j.cub.2004.11.039. PubMed DOI

Beal SJ, Grimm KJ, Dorn LD, Susman EJ. Morningness-Eveningness and Physical Activity in Adolescent Girls: Menarche as a Transition Point. Child Dev. 2016;87:1106–1114. doi: 10.1111/cdev.12539. PubMed DOI PMC

Broms U, et al. Long-term consistency of diurnal-type preferences among men. Chronobiol. Int. 2014;31:182–188. doi: 10.3109/07420528.2013.836534. PubMed DOI

Roenneberg T, Merrow M. Entrainment of the human circadian clock. Cold Spring Harb. Symp. Quant. Biol. 2007;72:293–299. doi: 10.1101/sqb.2007.72.043. PubMed DOI

Randler C. Age and gender differences in morningness-eveningness during adolescence. J. Genet. Psychol. 2011;172:302–308. doi: 10.1080/00221325.2010.535225. PubMed DOI

Merikanto I, et al. Relation of chronotype to sleep complaints in the general Finnish population. Chronobiol. Int. 2012;29:311–317. doi: 10.3109/07420528.2012.655870. PubMed DOI

Duarte LL, et al. Chronotype ontogeny related to gender. Braz. J. Med. Biol. Res. 2014;47:316–320. doi: 10.1590/1414-431x20143001. PubMed DOI PMC

Wright KP, Jr., et al. Entrainment of the human circadian clock to the natural light-dark cycle. Curr. Biol. 2013;23:1554–1558. doi: 10.1016/j.cub.2013.06.039. PubMed DOI PMC

Stothard ER, et al. Circadian Entrainment to the Natural Light-Dark Cycle across Seasons and the Weekend. Curr. Biol. 2017;27:508–513. doi: 10.1016/j.cub.2016.12.041. PubMed DOI PMC

Facer-Childs, E. R., Campos, B. M., Middleton, B., Skene, D. J. & Bagshaw, A. P. Circadian phenotype impacts the brain’s resting-state functional connectivity, attentional performance, and sleepiness. Sleep42, 10.1093/sleep/zsz033 (2019). PubMed PMC

Zerbini G, Kantermann T, Merrow M. Strategies to decrease social jetlag: Reducing evening blue light advances sleep and melatonin. Eur. J. Neurosci. 2018 doi: 10.1111/ejn.14293. PubMed DOI

Wittmann M, Dinich J, Merrow M, Roenneberg T. Social jetlag: misalignment of biological and social time. Chronobiol. Int. 2006;23:497–509. doi: 10.1080/07420520500545979. PubMed DOI

Novakova M, Sladek M, Sumova A. Human chronotype is determined in bodily cells under real-life conditions. Chronobiol. Int. 2013;30:607–617. doi: 10.3109/07420528.2012.754455. PubMed DOI

McHill AW, Wright KP., Jr. Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease. Obes. Rev. 2017;18(Suppl 1):15–24. doi: 10.1111/obr.12503. PubMed DOI

Roenneberg T, et al. Why Should We Abolish Daylight Saving Time? J. Biol. Rhythms. 2019;34:227–230. doi: 10.1177/0748730419854197. PubMed DOI PMC

Roenneberg T, Allebrandt KV, Merrow M, Vetter C. Social jetlag and obesity. Curr. Biol. 2012;22:939–943. doi: 10.1016/j.cub.2012.03.038. PubMed DOI

Roenneberg T, Kumar CJ, Merrow M. The human circadian clock entrains to sun time. Curr. Biol. 2007;17:R44–45. doi: 10.1016/j.cub.2006.12.011. PubMed DOI

Allebrandt KV, et al. Chronotype and sleep duration: the influence of season of assessment. Chronobiol. Int. 2014;31:731–740. doi: 10.3109/07420528.2014.901347. PubMed DOI

McKinney, W. Data Structures for Statistical Computing in Python. in Proceedings of the 9th Python in Science Conference. 51–56.

van der Walt S, Colbert SC, Varoquaux G. The NumPy Array: A Structure for Efficient Numerical Computation. Computing in Science & Engineering. 2011;13:22–30. doi: 10.1109/Mcse.2011.37. DOI

Seabold, S. & Perktold, J. Statsmodels: Econometric and statistical modeling with python. in 9th Python in Science Conference. (2010).

Terpilowski M. scikit-posthocs: Pairwise multiple comparison tests in Python. J Open Source Software. 2019;4:1169. doi: 10.21105/joss.01169. DOI

Jones, E., Oliphant, E. & Peterson, P. SciPy: Open Source Scientific Tools for Python (2001).

Waskom, M. L. et al. mwaskom/seaborn: v0.9.0 (2018).

Hunter JD. Matplotlib: A 2D Graphics Environment. Computing in Science & Engineering. 2007;9:90–95. doi: 10.1109/MCSE.2007.55. DOI

Levandovski R, Sasso E, Hidalgo MP. Chronotype: a review of the advances, limits and applicability of the main instruments used in the literature to assess human phenotype. Trends in Psychiatry and Psychotherapy. 2013;35:3–11. doi: 10.1590/S2237-60892013000100002. PubMed DOI

Horne JA, Ostberg O. A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. Int. J. Chronobiol. 1976;4:97–110. PubMed

Zavada A, Gordijn MC, Beersma DG, Daan S, Roenneberg T. Comparison of the Munich Chronotype Questionnaire with the Horne-Ostberg’s Morningness-Eveningness Score. Chronobiol. Int. 2005;22:267–278. doi: 10.1081/cbi-200053536. PubMed DOI

Bennie J, Davies TW, Duffy JP, Inger R, Gaston KJ. Contrasting trends in light pollution across Europe based on satellite observed night time lights. Sci. Rep. 2014;4:3789. doi: 10.1038/srep03789. PubMed DOI PMC

Carvalho FG, Hidalgo MP, Levandovski R. Differences in circadian patterns between rural and urban populations: an epidemiological study in countryside. Chronobiol. Int. 2014;31:442–449. doi: 10.3109/07420528.2013.846350. PubMed DOI

Fischer D, Lombardi DA, Marucci-Wellman H, Roenneberg T. Chronotypes in the US - Influence of age and sex. PLoS One. 2017;12:e0178782. doi: 10.1371/journal.pone.0178782. PubMed DOI PMC

Dijk DJ, Duffy JF, Czeisler CA. Contribution of circadian physiology and sleep homeostasis to age-related changes in human sleep. Chronobiol. Int. 2000;17:285–311. doi: 10.1081/cbi-100101049. PubMed DOI

Carskadon MA, Labyak SE, Acebo C, Seifer R. Intrinsic circadian period of adolescent humans measured in conditions of forced desynchrony. Neurosci. Lett. 1999;260:129–132. doi: 10.1016/s0304-3940(98)00971-9. PubMed DOI

Randler C, Engelke J. Gender differences in chronotype diminish with age: a meta-analysis based on morningness/chronotype questionnaires. Chronobiol. Int. 2019;36:888–905. doi: 10.1080/07420528.2019.1585867. PubMed DOI

Jankowski KS, Fajkowska M, Domaradzka E, Wytykowska A. Chronotype, social jetlag and sleep loss in relation to sex steroids. Psychoneuroendocrinology. 2019;108:87–93. doi: 10.1016/j.psyneuen.2019.05.027. PubMed DOI

Hollander LE, et al. Sleep quality, estradiol levels, and behavioral factors in late reproductive age women. Obstet. Gynecol. 2001;98:391–397. doi: 10.1016/s0029-7844(01)01485-5. PubMed DOI

Park YM, Matsumoto K, Seo YJ, Kang MJ, Nagashima H. Changes of sleep or waking habits by age and sex in Japanese. Percept. Mot. Skills. 2002;94:1199–1213. doi: 10.2466/pms.2002.94.3c.1199. PubMed DOI

Randler C, Kretz S. Assortative mating in morningness-eveningness. Int. J. Psychol. 2011;46:91–96. doi: 10.1080/00207594.2010.518237. PubMed DOI

Randler C, Barrenstein S, Vollmer C, Diaz-Morales JF, Jankowski KS. Women would like their partners to be more synchronized with them in their sleep-wake rhythm. Span. J. Psychol. 2014;17:E70. doi: 10.1017/sjp.2014.72. PubMed DOI

Roenneberg T, et al. Human activity and rest in situ. Methods Enzymol. 2015;552:257–283. doi: 10.1016/bs.mie.2014.11.028. PubMed DOI

Wong PM, Hasler BP, Kamarck TW, Muldoon MF, Manuck SB. Social Jetlag, Chronotype, and Cardiometabolic Risk. J. Clin. Endocrinol. Metab. 2015;100:4612–4620. doi: 10.1210/jc.2015-2923. PubMed DOI PMC

Merikanto I, et al. Associations of chronotype and sleep with cardiovascular diseases and type 2 diabetes. Chronobiol. Int. 2013;30:470–477. doi: 10.3109/07420528.2012.741171. PubMed DOI

Randler C, Haun J, Schaal S. Assessing the Influence of Sleep-Wake Variables on Body Mass Index (BMI) in Adolescents. Europe’s Journal of Psychology. 2013;9:339–347. doi: 10.5964/ejop.v9i2.558. DOI

Maukonen M, et al. The associations between chronotype, a healthy diet and obesity. Chronobiol. Int. 2016;33:972–981. doi: 10.1080/07420528.2016.1183022. PubMed DOI

Cespedes Feliciano EM, et al. Chronotype, Social Jet Lag, and Cardiometabolic Risk Factors in Early Adolescence. JAMA Pediatr. 2019 doi: 10.1001/jamapediatrics.2019.3089. PubMed DOI PMC

Munch M, Bromundt V. Light and chronobiology: implications for health and disease. Dialogues Clin. Neurosci. 2012;14:448–453. PubMed PMC

Roenneberg T, Winnebeck EC, Klerman EB. Daylight Saving Time and Artificial Time Zones - A Battle Between Biological and Social Times. Front. Physiol. 2019;10:944. doi: 10.3389/fphys.2019.00944. PubMed DOI PMC

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Population-representative study reveals cardiovascular and metabolic disease biomarkers associated with misaligned sleep schedules

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