Chronotype assessment via a large scale socio-demographic survey favours yearlong Standard time over Daylight Saving Time in central Europe

Abstract

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 timeuse 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.

The overlapping geography of cognitive ability and chronotype

“…In line with earlier research Sl adek et al, 2020), we found that respondents from lower longitudes with the same time zone had on average later chronotypes, a finding that generalizes across most individual time zones. These individuals experience sunset and sunrise times at a later clock time as a result of their more westward location within the time zone which entrains a later chronotype .…”

“…Since our method of estimating the latter two phenotypes was novel and relied on non-targeted questionnaire responses instead of proper psychometric scales, one goal of our study was to demonstrate the validity of this approach by replicating robust findings about our phenotypes. We successfully replicated previous findings about the relationship between age, sex and chronotype (Duarte et al, 2014;Fischer et al, 2017;Paine et al, 2006;Till Roenneberg et al, 2004;Sl adek et al, 2020;Tonetti et al, 2008), relative longitude and chronotype (Giuntella & Mazzonna, 2019;Sl adek et al, 2020) as well as city population and both chronotype and cognitive ability (Abdellaoui et al, 2019;Alexopoulos, 1997;Bass et al, 2008;Gist & Clark, 1938;Lehmann, 1959;Sl adek et al, 2020;Taji et al, 2019;Teasdale et al, 1988). Notably, we also found a modest positive relationship between cognitive ability and chronotype (β = .05), in line with a previous meta-analysis (Preckel et al, 2011) and a large study (Kanazawa & Perina, 2009).…”

“…Genetic factors account for up to 50% of individual differences in chronotype at the same age (Inderkum & Tarokh, 2018;Jones et al, 2019;Koskenvuo et al, 2007), but environmental determinants are also important. Artificial light in the evening delays the sleep-wake cycle (Figueiro et al, 2014;Porcheret et al, 2018;Shawa et al, 2018), but so does the variation of the timing of the day-night cycle within the time zone, with individuals living in the western (Giuntella & Mazzonna, 2019;Sl adek et al, 2020) and northern (Leocadio-Miguel et al, 2017;Miguel et al, 2014;Porcheret et al, 2018) parts of the same time zone having a later chronotype. Some evidence suggests that living in a larger inhabited area also contributes to a later chronotype, presumably because of increased artificial lighting and more opportunities for nocturnal activity Sl adek et al, 2020).…”

“…Artificial light in the evening delays the sleep-wake cycle (Figueiro et al, 2014;Porcheret et al, 2018;Shawa et al, 2018), but so does the variation of the timing of the day-night cycle within the time zone, with individuals living in the western (Giuntella & Mazzonna, 2019;Sl adek et al, 2020) and northern (Leocadio-Miguel et al, 2017;Miguel et al, 2014;Porcheret et al, 2018) parts of the same time zone having a later chronotype. Some evidence suggests that living in a larger inhabited area also contributes to a later chronotype, presumably because of increased artificial lighting and more opportunities for nocturnal activity Sl adek et al, 2020). Individual differences in chronotypeespecially a late chronotypemay result in a misalignment of the daily rhythm of society and negatively impact health (Castilhos Beauvalet et al, 2017;Knutson & von Schantz, 2018;Partonen, 2015;Vetter et al, 2015;Wittmann et al, 2006).…”

It’s About Time: The Circadian Network as Time-Keeper for Cognitive Functioning, Locomotor Activity and Mental Health

“…Despite extensive investigation of parental sleep patterns and quality during pregnancy and following childbirth as well as its relationship with mental health complications ( Deforges et al, 2021 ), only little is known about parental circadian rhythm during this time. Initial evidence suggests that parenthood is linked with an early chronotype ( Sládek et al, 2020 ). Further, parental circadian rhythm amplitude may be decreased following birth ( Wulff and Siegmund, 2000 ), which can be observed as a result of irregular sleep-wake patterns or disturbance and may accumulate to circadian rhythm sleep disorder ( Zee and Vitiello, 2009 ).…”