1
|
Olivera A, Estevan I, Tassino B, Rossel C, Silva A. Epidemiology of sleep patterns and circadian typology in uruguayan children: The contribution of school shifts. Sleep Med X 2024; 7:100099. [PMID: 38234312 PMCID: PMC10792258 DOI: 10.1016/j.sleepx.2023.100099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/13/2023] [Accepted: 12/18/2023] [Indexed: 01/19/2024] Open
Abstract
Healthy sleep is defined by the combination of adequate duration, good quality, and regular timing. In children, sleep thus depends on the interplay of individual, parental, organizational, community, and social variables, but only a few studies have addressed this issue in a comprehensive way nationwide. Using the Uruguayan nationally representative survey (Nutrition, Child Development, and Health Survey, Encuesta de Nutrición, Desarrollo Infantil y Salud, ENDIS), we present the first epidemiological characterization of chronobiological and sleep parameters in Latin American children. On average, Uruguayan urban children (n = 2437; 5-10-years old) showed quite late chronotypes (MSFsc = 03:53 ± 1:07), moderate misalignment (SJL = 1.0 ± 0.9 h), and adequate sleep duration (SDweek = 9.9 ± 1.0 h). Further, we show the substantial influence of school shift schedules on children's circadian typology and sleep patterns. Our results show that children attending the morning school shift have a higher risk of sleep problems than afternoon-school shift ones. The chronotype and sleep were earlier in morning-school shift children than in children attending the afternoon school shift. However, morning-school shift children had stronger misalignment, shorter sleep on school days, and a higher risk of chronic sleep deficit and non-healthy circadian misalignment (even worse in late chronotypes) than afternoon-shift children. This evidence points to the need of evaluating policies to reorganize school start times to prevent the negative effects that early schooling seems to have on children's sleep health, which has been neglected so far.
Collapse
Affiliation(s)
- Andrés Olivera
- Grupo Cronobiología, Comisión Sectorial de Investigación Científica, Universidad de la República, Jackson 1301, 11200, Montevideo, Uruguay
- Departamento de Ciencias Sociales, Universidad Católica del Uruguay, 8 de octubre 2768, 11600, Montevideo, Uruguay
| | - Ignacio Estevan
- Grupo Cronobiología, Comisión Sectorial de Investigación Científica, Universidad de la República, Jackson 1301, 11200, Montevideo, Uruguay
- Programa de Neuropsicología y Neurobiología, Facultad de Psicología, Universidad de la República, Tristán Narvaja 1674, 11200, Montevideo, Uruguay
| | - Bettina Tassino
- Grupo Cronobiología, Comisión Sectorial de Investigación Científica, Universidad de la República, Jackson 1301, 11200, Montevideo, Uruguay
- Sección Etología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Cecilia Rossel
- Departamento de Ciencias Sociales, Universidad Católica del Uruguay, 8 de octubre 2768, 11600, Montevideo, Uruguay
| | - Ana Silva
- Grupo Cronobiología, Comisión Sectorial de Investigación Científica, Universidad de la República, Jackson 1301, 11200, Montevideo, Uruguay
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| |
Collapse
|
2
|
Rodríguez Ferrante G, Leone MJ. Solar clock and school start time effects on adolescents' chronotype and sleep: A review of a gap in the literature. J Sleep Res 2024; 33:e13974. [PMID: 37370220 DOI: 10.1111/jsr.13974] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/11/2023] [Accepted: 06/11/2023] [Indexed: 06/29/2023]
Abstract
Circadian rhythms are entrained by external factors such as sunlight and social cues, but also depend on internal factors such as age. Adolescents exhibit late chronotypes, but worldwide school starts early in the morning leading to unhealthy sleep habits. Several studies reported that adolescents benefit from later school start times. However, the effect of later school start time on different outcomes varies between studies, and most previous literature only takes into consideration the social clock (i.e. local time of school starting time) but not the solar clock (e.g. the distance between school start time and sunrise). Thus, there is an important gap in the literature: when assessing the effect of a school start time on chronotype and sleep of adolescents at different locations and/or seasons, the solar clock might differ and, consistently, the obtained results. For example, the earliest school start time for adolescents has been suggested to be 08:30 hours, but this school start time might correspond to different solar times at different times of the year, longitudes and latitudes. Here, we describe the available literature comparing different school start times, considering important factors such as geographic position, nationality, and the local school start time and its distance to sunrise. Then, we described and contrasted the relative role of both social and solar clocks on the chronotype and sleep of adolescents. As a whole, we point and discuss a gap in literature, suggesting that both clocks are relevant when addressing the effect of school start time on adolescents' chronotype and sleep.
Collapse
Affiliation(s)
- Guadalupe Rodríguez Ferrante
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Buenos Aires, Argentina
- Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Buenos Aires, Argentina
| | - María Juliana Leone
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Buenos Aires, Argentina
- Área de Educación, Escuela de Gobierno, Universidad Torcuato Di Tella, Buenos Aires, Argentina
| |
Collapse
|
3
|
Gabaldón-Estevan D, Carmona-Talavera D, Catalán-Gregori B, Mañas-García E, Martin-Carbonell V, Monfort L, Martinez-Besteiro E, González-Carrasco M, Hernández-Jiménez MJ, Täht K, Talavera M, Ancheta-Arrabal A, Sáez G, Estany N, Pin-Arboledas G, Reis C. Kairos study protocol: a multidisciplinary approach to the study of school timing and its effects on health, well-being and students' performance. Front Public Health 2024; 12:1336028. [PMID: 38525330 PMCID: PMC10957785 DOI: 10.3389/fpubh.2024.1336028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/26/2024] [Indexed: 03/26/2024] Open
Abstract
Recent evidence from chronobiology, chssronomedicine and chronopsychology shows that the organisation of social time (e.g., school schedules) generally does not respect biological time. This raises concerns about the impact of the constant mismatch between students' social and internal body clocks on their health, well-being and academic performance. The present paper describes a protocol used to investigate the problem of (de) synchronisation of biological times (chronotypes) in childhood and youth in relation to school times. It studies the effects of student chronotype vs. school schedule matches/mismatches on health behaviours (e.g., how many hours students sleep, when they sleep, eat, do physical activity, spend time outdoors in daylight) and learning (verbal expression, spatial structuring, operations) and whether alert-fatigue levels mediate this effect alignments/misalignments on learning (verbal expression, spatial structuring, operations) and their mediation by alert-fatigue levels. The novelty of our protocol lies in its multidisciplinary and mixed methodology approach to a relevant and complex issue. It draws on up-to-date knowledge from the areas of biology, medicine, psychology, pedagogy and sociology. The methods employed include a varied repertoire of techniques from hormonal analysis (cortisol and melatonin), continuous activity and light monitoring, self-registration of food intake, sleep timings, exercise and exposure to screens, alongside with systematic application of cognitive performance tests (e.g., memory, reasoning, calculation, attention) and self-reported well-being. This comprehensive and interdisciplinary protocol should support evidence-based education policy measures related to school time organisation. Appropriate and healthier school timetables will contribute to social change, healthier students and with more efficient learning. The results of studies using a similar methodology in other countries would ensure replication and comparability of results and contribute to knowledge to support policy making.
Collapse
Affiliation(s)
| | | | | | - Elena Mañas-García
- Department of Sociology and Social Anthropology, University of Valencia, Valencia, Spain
| | | | - Lucía Monfort
- Department of Pediatrics, Clinical University Hospital, Valencia, Spain
| | - Elvira Martinez-Besteiro
- Department of Personality, Assessment and Psychological Treatments, University of Valencia, Valencia, Spain
| | | | | | - Kadri Täht
- Institute of International Social Studies, School of Governance, Law and Society, Tallinn University, Tallinn, Estonia
| | - Marta Talavera
- Department of Experimental and Social Sciences Teaching, University of Valencia, Valencia, Spain
| | - Ana Ancheta-Arrabal
- Department of Comparative Education and History of Education, University of Valencia, Valencia, Spain
| | - Guillermo Sáez
- Service of Clinical Analysis, University Hospital Dr. Peset, Valencia, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Nuria Estany
- Service of Clinical Analysis, University Hospital Dr. Peset, Valencia, Spain
| | - Gonzalo Pin-Arboledas
- Grupo de Sueño y Cronobiologia de la Asociación Española de Pediatría, Valencia, Spain
| | - Catia Reis
- CRC-W - Faculdade de Ciências Humanas, Universidade Católica Portuguesa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, IMM, Lisboa, Lisbon, Portugal
- ISAMB - Faculdade de Medicina Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
4
|
Ohashi M, Eto T, Takasu T, Motomura Y, Higuchi S. Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning. Clocks Sleep 2023; 5:615-626. [PMID: 37873842 PMCID: PMC10594521 DOI: 10.3390/clockssleep5040041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023] Open
Abstract
Humans have a circadian rhythm for which the period varies among individuals. In the present study, we investigated the amount of natural phase delay of circadian rhythms after spending a day under dim light (Day 1 to Day 2) and the amount of phase advance due to light exposure (8000 lx, 4100 K) the following morning (Day 2 to Day 3). The relationships of the phase shifts with the circadian phase, chronotype and sleep habits were also investigated. Dim light melatonin onset (DLMO) was investigated as a circadian phase marker on each day. In the 27 individuals used for the analysis, DLMO was delayed significantly (-0.24 ± 0.33 h, p < 0.01) from Day 1 to Day 2 and DLMO was advanced significantly (0.18 ± 0.36 h, p < 0.05) from Day 2 to Day 3. There was a significant correlation between phase shifts, with subjects who had a greater phase delay in the dim environment having a greater phase advance by light exposure (r = -0.43, p < 0.05). However, no significant correlations with circadian phase, chronotype or sleep habits were found. These phase shifts may reflect the stability of the phase, but do not account for an individual's chronotype-related indicators.
Collapse
Affiliation(s)
- Michihiro Ohashi
- Graduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka 815-8540, Japan; (M.O.)
- Research Fellow of the Japan Society for the Promotion of Science, Fukuoka 815-8540, Japan
| | - Taisuke Eto
- Research Fellow of the Japan Society for the Promotion of Science, Fukuoka 815-8540, Japan
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan
- Department of Sleep-Wake Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo 187-8551, Japan
| | - Toaki Takasu
- Graduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka 815-8540, Japan; (M.O.)
| | - Yuki Motomura
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan
| | - Shigekazu Higuchi
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan
| |
Collapse
|
5
|
Borisenkov MF, Tserne T, Bakutova L, Smirnov V, Popov S. Afternoon school shift is associated with increased risk of overweight/obesity in 11-14-year-old females with early and intermediate chronotype. Pediatr Obes 2023; 18:e13039. [PMID: 37095615 DOI: 10.1111/ijpo.13039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/26/2023]
Abstract
OBJECTIVE The purpose of this study was to compare the anthropometric and sleep-wake rhythm characteristics of schoolchildren that attend school in morning and afternoon school shifts. METHODS We recruited 18 481 individuals (females: 56.4%) aged 11 to 18 years old with an average age of 14.4 ± 1.7 years old. In total, 812 (4.2%) questionnaires were incomplete. The self-reported height and weight were used to assess the sex- and age-corrected body mass index of the participants. The Munich ChronoType Questionnaire was used to assess the chronotype, social jetlag, and sleep duration of the participants. RESULTS In total, 12.6% of the participants were affected by overweight or obesity. The overweight and obesity incidence rate was higher among the students studying in the afternoon (odd ratio [95%CI]: 1.33 [1.16-1.52]). The afternoon school shift had a negative impact on the anthropometric indicators only in the 11-14-year-olds (1.29 [1.11-1.50]) and girls (1.26 [1.04-1.54]) with an early (1.27 [1.03-1.56]) and intermediate (1.30 [1.07-1.58]) chronotype. CONCLUSION The data obtained indicated that the afternoon school shift is not ideal, especially for female children and adolescents under 15 years old with an early and intermediate chronotype.
Collapse
Affiliation(s)
- Mikhail F Borisenkov
- Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Komi Science Center of Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
| | - Tatyana Tserne
- Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Komi Science Center of Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
| | - Larisa Bakutova
- Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Komi Science Center of Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
| | - Vasily Smirnov
- Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Komi Science Center of Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
| | - Sergey Popov
- Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Komi Science Center of Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
| |
Collapse
|
6
|
Arrona-Palacios A, Díaz-Morales JF, Duffy JF. The influence of a permanent double-shift school start time on adolescent sleep and chronotype across different age groups. Chronobiol Int 2023; 40:850-863. [PMID: 37212086 DOI: 10.1080/07420528.2023.2215343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 05/23/2023]
Abstract
The main objective of this study was to explore the differences in sleep habits and chronotype across different age groups in Mexican adolescents attending a permanent double-shift school system. This cross-sectional study consisted of 1,969 (1,084 girls) students from public elementary, secondary, and high schools, as well as undergraduate university students from Mexico. Age range was 10-22 [15.33 ± 3.28 (mean ± SD)] years, 988 morning shift and 981 afternoon shift students. Questions regarding usual self-reported bedtime and rise time were collected, and from that, estimates for time in bed, midpoint of sleep, social jetlag, and chronotype were evaluated. Afternoon shift students reported later rise times, bedtimes, midpoint of sleep, and longer time in bed on school days than morning shift students, as well as less social jetlag. Overall, afternoon shift students reported a later chronotype than morning shift students. Peak lateness of chronotype in afternoon shift students was at age 15, with girls peaking at age 14 and boys at age 15. Meanwhile, morning shift students reported peak lateness of chronotype around age 20. In this study, adolescents from different age ranges attending an extremely delayed school start time reported adequate sleep compared with adolescents attending a fixed morning school start time. In addition, the analysis presented in this study seems to suggest that the peak of late chronotype may be influenced by school start times.
Collapse
Affiliation(s)
- Arturo Arrona-Palacios
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
- Writing Lab, Institute for the Future of Education, Tecnologico de Monterrey, Monterrey, Mexico
| | - Juan F Díaz-Morales
- Department of Social Psychology, Work and Individual Differences, Faculty of Psychology, Complutense University of Madrid, Madrid, Spain
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
7
|
Rodríguez Ferrante G, Goldin AP, Sigman M, Leone MJ. A better alignment between chronotype and school timing is associated with lower grade retention in adolescents. NPJ SCIENCE OF LEARNING 2023; 8:21. [PMID: 37344483 DOI: 10.1038/s41539-023-00171-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
Schools start early in the morning all over the world, contrasting with adolescents' late chronotype. Interestingly, lower academic performance (i.e. grades or qualifications) was associated with later chronotypes. However, it is unclear whether it is a direct effect of chronotype or because students attend school too early to perform at their best. Moreover, little is known about how this affects students' academic success beyond their grades. To address this gap in knowledge, we studied how school timing and chronotype affect grade retention (i.e. repeat a year) in a unique sample of students randomly assigned to one of three different school timings (starting at 07:45, 12:40, or 17:20). Even when controlling for academic performance, we found that later chronotypes exhibit higher odds of grade retention only in the morning, but not in later school timings. Altogether, ensuring a better alignment between school timing and students' biological rhythms might enhance future opportunities of adolescents.
Collapse
Affiliation(s)
- Guadalupe Rodríguez Ferrante
- Universidad Torcuato Di Tella, CONICET, Laboratorio de Neurociencia, C1428BIJ, Buenos Aires, Argentina.
- Universidad Nacional de Quilmes, CONICET, Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, B1876BXD, Bernal, Buenos Aires, Argentina.
| | - Andrea P Goldin
- Universidad Torcuato Di Tella, CONICET, Laboratorio de Neurociencia, C1428BIJ, Buenos Aires, Argentina
| | - Mariano Sigman
- Universidad Torcuato Di Tella, CONICET, Laboratorio de Neurociencia, C1428BIJ, Buenos Aires, Argentina
- Facultad de Lenguas y Educación, Universidad Nebrija, Madrid, Spain
| | - María Juliana Leone
- Universidad Nacional de Quilmes, CONICET, Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, B1876BXD, Bernal, Buenos Aires, Argentina
- Universidad Torcuato Di Tella, CONICET, Área de Educación, Escuela de Gobierno, C1428BIJ, Buenos Aires, Argentina
| |
Collapse
|
8
|
Bruno S, Benedetti D, Bazzani A, Ferri F, Granieri I, Cruz-Sanabria F, Fiori S, d'Ascanio P, Frumento P, Faraguna U. School Attendance, Chronotype, and Day-of-the-Week Effect in Adolescent Male Basketball Players. J Biol Rhythms 2023; 38:185-196. [PMID: 36680409 DOI: 10.1177/07487304221144340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Adolescents' conflict between circadian rhythm and early school start time is more pronounced in evening chronotypes, who tend to reduce sleep duration during school days compensating during the free days by oversleeping (i.e., social jetlag). Cumulative weekly sleep debt may impair sport performance, which relies on physical and cognitive skills modulated by sleep. We hypothesized that chronotype predicts sport performance, and that it may interact with the day of the week. Moreover, given the role sleep plays in motor memory consolidation, we tested the hypothesis that school attendance, and the related chronic sleep deprivation, might be detrimental for participants in a training phase. Ninety-three adolescent male basketball players performed multiple free throw sessions (n = 7880) during both the school and holiday periods. Chronotype and its interaction with the day of the week significantly predicted shooting accuracy when attending school, but not on holidays. Evening types' performance gradually decreased from Monday to Friday. Participants with a more unstable performance (i.e., who did not complete the acquisition of the free throw motor scheme) worsened their accuracy when attending school. Our results suggest that the impact of chronotype and day of the week on sport performance is related to the presence of an externally imposed sleep/wake schedule and is consistent with evening types' increased likelihood of experiencing social jetlag. Possibly due to early school start time, attending school worsened the performance of participants in a training phase. Further investigations are required to assess whether reducing the mismatch between biological and social clocks might improve sport performance, along with other aspects of adolescents' life.
Collapse
Affiliation(s)
- Simone Bruno
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Davide Benedetti
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Andrea Bazzani
- Institute of Management, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Francesca Ferri
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Iacopo Granieri
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Francy Cruz-Sanabria
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Simona Fiori
- Department of Developmental Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Fondazione Stella Maris, Pisa, Italy
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Paola d'Ascanio
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Paolo Frumento
- Department of Political Sciences, University of Pisa, Pisa, Italy
| | - Ugo Faraguna
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
- Department of Developmental Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Fondazione Stella Maris, Pisa, Italy
| |
Collapse
|
9
|
The Influence of Light and Physical Activity on the Timing and Duration of Sleep: Insights from a Natural Model of Dance Training in Shifts. Clocks Sleep 2023; 5:47-61. [PMID: 36810843 PMCID: PMC9945127 DOI: 10.3390/clockssleep5010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/19/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Environmental, social, and behavioral variables influence sleep timing and duration. Using wrist-worn accelerometers, we recorded 31 dancers (age = 22.6 ± 3.5) for 17 days and who trained either in the morning (n = 15) or in the late evening (n = 16). We estimated the dancers' daily sleep pattern: onset, end, and duration. In addition, their minutes of moderate-to-vigorous physical activity (MVPA) and mean light illuminance were also calculated daily and for the morning-shift and late-evening-shift time windows. On training days, the shifts involved differences in sleep timing, alarm-driven waking frequency, and the pattern of light exposure and MVPA duration. Sleep was strongly advanced when dancers trained in the morning and when alarms were used, while morning light had a low influence. Sleep was delayed when dancers were more exposed to light and displayed longer MVPA during the late evening. Sleep duration was strongly reduced on weekends and when alarms were used. A small reduction in sleep duration was also observed when morning illuminance was lower or when late evening MVPA was longer. Training in shifts influenced the timing of environmental and behavioral factors, which added up to shape dancers' sleep timing and duration.
Collapse
|
10
|
Rodríguez Ferrante G, Goldin AP, Sigman M, Leone MJ. Chronotype at the beginning of secondary school and school timing are both associated with chronotype development during adolescence. Sci Rep 2022; 12:8207. [PMID: 35581310 PMCID: PMC9114414 DOI: 10.1038/s41598-022-11928-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 05/03/2022] [Indexed: 11/09/2022] Open
Abstract
The misalignment between late chronotypes and early school start times affect health, performance and psychological well-being of adolescents. Here we test whether, and how, the baseline chronotype (i.e. chronotype at the beginning of secondary school) and the school timing affect the magnitude and the direction of the developmental change in chronotype during adolescence. We evaluated a sample of Argentinian students (n = 259) who were randomly assigned to attend school in the morning (07:45 a.m.–12:05 p.m.), afternoon (12:40 p.m.–05:00 p.m.) or evening (05:20 p.m.–09:40 p.m.) school timings. Importantly, chronotype and sleep habits were assessed longitudinally in the same group of students along secondary school (at 13–14 y.o. and 17–18 y.o.). Our results show that: (1) although chronotypes partially align with class time, this effect is insufficient to fully account for the differences observed in sleep-related variables between school timings; (2) both school timing and baseline chronotype are independently associated with the direction and the magnitude of change in chronotype, with greater delays related to earlier baseline chronotypes and later school timings. The practical implications of these results are challenging and should be considered in the design of future educational timing policies to improve adolescents’ well-being.
Collapse
Affiliation(s)
- Guadalupe Rodríguez Ferrante
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Av. Figueroa Alcorta, C1428BCW, CABA, C1428BIJ7350, Buenos Aires, Argentina.,Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Roque S. Peña 352, B1876BXD Bernal, Buenos Aires, Argentina
| | - Andrea Paula Goldin
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Av. Figueroa Alcorta, C1428BCW, CABA, C1428BIJ7350, Buenos Aires, Argentina
| | - Mariano Sigman
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Av. Figueroa Alcorta, C1428BCW, CABA, C1428BIJ7350, Buenos Aires, Argentina.,Facultad de Lenguas y Educación, Universidad Nebrija, Madrid, Spain
| | - María Juliana Leone
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, CONICET, Av. Figueroa Alcorta, C1428BCW, CABA, C1428BIJ7350, Buenos Aires, Argentina. .,Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Roque S. Peña 352, B1876BXD Bernal, Buenos Aires, Argentina.
| |
Collapse
|
11
|
Estevan I, Tassino B, Vetter C, Silva A. Challenged by extremely irregular school schedules, Uruguayan adolescents only set their waking time. J Adolesc 2022; 94:488-492. [DOI: 10.1002/jad.12036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/18/2022] [Accepted: 02/17/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Ignacio Estevan
- Programa de Neuropsicología y Neurobiología, Facultad de Psicología Universidad de la República Montevideo Uruguay
| | - Bettina Tassino
- Sección Etología; Facultad de Ciencias Universidad de la República Montevideo Uruguay
| | - Céline Vetter
- Department of Integrative Physiology University of Colorado Boulder Boulder Colorado USA
| | - Ana Silva
- Laboratorio de Neurociencias, Facultad de Ciencias Universidad de la República Montevideo Uruguay
| |
Collapse
|
12
|
A 4-year longitudinal study investigating the relationship between flexible school starts and grades. Sci Rep 2022; 12:3178. [PMID: 35210437 PMCID: PMC8873390 DOI: 10.1038/s41598-022-06804-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/25/2022] [Indexed: 11/21/2022] Open
Abstract
The mismatch between teenagers’ late sleep phase and early school start times results in acute and chronic sleep reductions. This is not only harmful for learning but may reduce career prospects and widen social inequalities. Delaying school start times has been shown to improve sleep at least short-term but whether this translates to better achievement is unresolved. Here, we studied whether 0.5–1.5 years of exposure to a flexible school start system, with the daily choice of an 8 AM or 8:50 AM-start, allowed secondary school students (n = 63–157, 14–21 years) to improve their quarterly school grades in a 4-year longitudinal pre-post design. We investigated whether sleep, changes in sleep or frequency of later starts predicted grade improvements. Mixed model regressions with 5111–16,724 official grades as outcomes did not indicate grade improvements in the flexible system per se or with observed sleep variables nor their changes—the covariates academic quarter, discipline and grade level had a greater effect in our sample. Importantly, our finding that intermittent sleep benefits did not translate into detectable grade changes does not preclude improvements in learning and cognition in our sample. However, it highlights that grades are likely suboptimal to evaluate timetabling interventions despite their importance for future success.
Collapse
|
13
|
Sleep improvements on days with later school starts persist after 1 year in a flexible start system. Sci Rep 2022; 12:2787. [PMID: 35181701 PMCID: PMC8857191 DOI: 10.1038/s41598-022-06209-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/10/2022] [Indexed: 11/09/2022] Open
Abstract
Early school times fundamentally clash with the late sleep of teenagers. This mismatch results in chronic sleep deprivation posing acute and long-term health risks and impairing students' learning. Despite immediate short-term benefits for sleep, the long-term effects of later starts remain unresolved. In a pre-post design over 1 year, we studied a unique flexible school start system, in which 10–12th grade students chose daily between an 8:00 or 8:50AM-start. Missed study time (8:00–8:50) was compensated for during gap periods or after classes. Based on 2 waves (6–9 weeks of sleep diary each), we found that students maintained their ~ 1-h-sleep gain on later days, longitudinally (n = 28) and cross-sectionally (n = 79). This gain was independent of chronotype and frequency of later starts but attenuated for boys after 1 year. Students showed persistently better sleep quality and reduced alarm-driven waking and reported psychological benefits (n = 93) like improved motivation, concentration, and study quality on later days. Nonetheless, students chose later starts only infrequently (median 2 days/week), precluding detectable sleep extensions in the flexible system overall. Reasons for not choosing late starts were the need to make up lost study time, preference for extra study time and transport issues. Whether flexible systems constitute an appealing alternative to fixed delays given possible circadian and psychological advantages warrants further investigation.
Collapse
|
14
|
Estevan I, Tassino B, Vetter C, Silva A. Bidirectional association between light exposure and sleep in adolescents. J Sleep Res 2021; 31:e13501. [PMID: 34608708 DOI: 10.1111/jsr.13501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/15/2021] [Accepted: 09/02/2021] [Indexed: 01/10/2023]
Abstract
Sleep behaviour is controlled by both circadian and homeostatic influences. Changes in both factors are related to the delayed sleep timing observed in adolescence, which also generates restrictions in their sleep duration. In addition, the circadian factor explains part of the observed influence of light on sleep duration. We recorded 15 high-school students for 23 days (vacation: 11 days; school term: 12 days) using GENEactive accelerometers. We employed a repeated-measures analysis to explore the day-to-day bidirectional association between mean light exposure and sleep behaviour across a period with extreme variability in social pressures. Sleep onset was more than 30 min earlier and sleep duration almost 20 min longer when previous day light was 10 times more intense. Light intensity had a reduction of more than 20% as sleep ended 1 hr later. Besides, sleep onset and offset were both later during vacation than on school days (almost 2 hr and 4 hr, respectively) and free days (almost 1 hr, respectively). Therefore, sleep duration was almost 2 hr longer on vacation and free days than on school days. On the other hand, light exposure intensity was twice as high during vacation days when adjusted by sleep timing. Insufficient sleep duration is a major problem for adolescents. Although we found that light exposure was associated with longer sleep duration, the influence of school start times was greater and ended up prevailing, which explained the short sleep durations observed on school days.
Collapse
Affiliation(s)
- Ignacio Estevan
- Programa de Neuropsicología y Neurobiología, Facultad de Psicología, Universidad de la República, Montevideo, Uruguay
| | - Bettina Tassino
- Sección Etología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Céline Vetter
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Ana Silva
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| |
Collapse
|
15
|
Shochat T, Santhi N, Herer P, Dijk DJ, Skeldon AC. Sleepiness is a signal to go to bed: data and model simulations. Sleep 2021; 44:6276242. [PMID: 33991415 PMCID: PMC8503825 DOI: 10.1093/sleep/zsab123] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 04/19/2021] [Indexed: 12/16/2022] Open
Abstract
Study Objectives Assess the validity of a subjective measure of sleepiness as an indicator of sleep drive by quantifying associations between intraindividual variation in evening sleepiness and bedtime, sleep duration, and next morning and subsequent evening sleepiness, in young adults. Methods Sleep timing and sleepiness were assessed in 19 students in late autumn and late spring on a total of 771 days. Karolinska Sleepiness Scales (KSS) were completed at half-hourly intervals at fixed clock times starting 4 h prior to participants’ habitual bedtime, and in the morning. Associations between sleepiness and sleep timing were evaluated by mixed model and nonparametric approaches and simulated with a mathematical model for the homeostatic and circadian regulation of sleepiness. Results Intraindividual variation in evening sleepiness was very large, covering four or five points on the 9-point KSS scale, and was significantly associated with subsequent sleep timing. On average, a one point higher KSS value was followed by 20 min earlier bedtime, which led to 11 min longer sleep, which correlated with lower sleepiness next morning and the following evening. Associations between sleepiness and sleep timing were stronger in early compared to late sleepers. Model simulations indicated that the directions of associations between sleepiness and sleep timing are in accordance with their homeostatic and circadian regulation, even though much of the variance in evening sleepiness and details of its time course remain unexplained by the model. Conclusion Subjective sleepiness is a valid indicator of the drive for sleep which, if acted upon, can reduce insufficient sleep.
Collapse
Affiliation(s)
- Tamar Shochat
- Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Nayantara Santhi
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Department of Psychology, Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, United Kingdom
| | - Paula Herer
- Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,UK Dementia Research Institute, Care Research & Technology Centre, at Imperial College London and the University of Surrey, Guildford, United Kingdom
| | - Anne C Skeldon
- UK Dementia Research Institute, Care Research & Technology Centre, at Imperial College London and the University of Surrey, Guildford, United Kingdom.,Department of Mathematics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, United Kingdom
| |
Collapse
|
16
|
Estevan I. Psychometric properties of the Morningness/Eveningness scale for children among Uruguayan adolescents: the role of school start times. BIOL RHYTHM RES 2020. [DOI: 10.1080/09291016.2020.1846284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Ignacio Estevan
- Programa de Neuropsicología y Neurobiología, Facultad de Psicología, Universidad de la República, Montevideo, Uruguay
| |
Collapse
|