The Perfect Hurricane in Latin America: School Start Time, Chronotype, Sleep, and Academic Performance During Adolescence

Solar clock and school start time effects on adolescents' chronotype and sleep: A review of a gap in the literature

“…However, daily social cues also affect circadian rhythms (Goldin et al, 2020;Rodríguez Ferrante et al, 2022;Skeldon et al, 2017) and, then, we expect that the social clock will also contribute to this phenomenon.…”

“…On the one hand, a later SST LT is expected to be associated with later MSFsc (Goldin et al, 2020; F I G U R E 7 Data extracted from studies comparing different school start times (SST). Data presented in these plots are mean values (or estimations made from data) reported in the original studies (Arrona-Palacios et al, 2015Boergers et al, 2014;Borlase et al, 2013;Brandalize et al, 2011;Carskadon et al, 1998;Carvalho-Mendes et al, 2020;Chan et al, 2017;Das-Friebel et al, 2020;Dexter et al, 2003;Dunster et al, 2018;Escribano & Díaz-Morales, 2014;Estevan et al, 2020;Goldin et al, 2020;Lo et al, 2018;Martin et al, 2016;Mello et al, 2001;O'Malley & O'Malley, 2008;Owens et al, 2010Owens et al, , 2017Perkinson-Gloor et al, 2013;Rodríguez Ferrante, Goldin, & Leone, 2022;Short et al, 2013;Thacher & Onyper, 2016Wahlstrom, 1997Wahlstrom, , 2002Wahlstrom et al, 2014;Widome et al, 2020;Wolfson et al, 2007;Yilmaz et al, 2011). Sleep duration on weekdays (SDw), social jetlag (SJL) and midpoint of sleep on free days sleep-corrected (MSFsc) were calculated from mean sleep timings when not reported in original works.…”

“…That is why, in order to obtain a value of chronotype not influenced by oversleeping, MSF has to be corrected. In this case, the correction results in an MSFsc equal to MSF in the absence of oversleeping (as shown in SST, functioning as a regular social cue, affects students' chronotype (Estevan et al, 2020;Goldin et al, 2020;Rodríguez Ferrante et al, 2022). Students attending school early in the morning present earlier chronotypes than afternoon-attending students.…”

“…morning-attending students present around 1.5 hr earlier chronotypes; Goldin et al, 2020;Rodríguez Ferrante et al, 2022a). The latter indicates that an early morning SST in not enough to fully align students' chronotype to this early schedule, which is also evidenced by the fact that adolescents are chronically sleep deprived and present high levels of SJL when attending to early morning school timing (Goldin et al, 2020;Rodríguez Ferrante et al, 2022).…”

“…Contrastingly, in the second situation (07:45 hours in October, 08:15 hours in June), even though the ΔSST LT is 30 min, an underestimation of the effect of the SST delay is expected because the hours of sunlight before school are reduced (À70 min) even when the SST LT is delayed: school started 88 min after sunrise at 07:45 hours in October and only 18 min after sunrise at 08:15 hours in June.Nevertheless, little is known about the relative influence of social and solar clocks on the effect of SST on adolescents' chronotype and sleep habits. Importantly, although later SSTs were mostly associated with improved sleep habits, there is large variability in the magnitude of the reported effects(Carvalho-Mendes et al, 2020;Dunster et al, 2018;Goldin et al, 2020;Meltzer et al, 2021;Rodríguez Ferrante et al, 2022). In that sense and associated with the relationship between solar and social clocks, there exist at least three possiblescenarios.…”