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![Average sleep duration as a function of age. (a) Weekly averages of sleep duration. (b) Sleep duration for free days (open circles) and for workdays (grey dots). Curves are polynomial fits; vertical lines represent Standard Errors of the Mean (± SEM; in most cases they are larger than the respective symbols). © [Rightsholder]. Reproduced with permission of Foster et al. (201319.
Foster, R. G., S. N. Peirson, K. Wulff, E. Winnebeck, C. Vetter, and T. Roenneberg. 2013. “Sleep and Circadian Rhythm Disruption in Social Jetlag and Mental Illness.” Progress in Molecular Biology and Translational Science 119: 325–346. doi:10.1016/B978-0-12-396971-2.00011-7View all references).](profile/Paul-Kelley-4/publication/271991912/figure/fig2/AS:306610695098370@1450113094141/Average-sleep-duration-as-a-function-of-age-a-Weekly-averages-of-sleep-duration-b.png)
Average sleep duration as a function of age. (a) Weekly averages of sleep duration. (b) Sleep duration for free days (open circles) and for workdays (grey dots). Curves are polynomial fits; vertical lines represent Standard Errors of the Mean (± SEM; in most cases they are larger than the respective symbols). © [Rightsholder]. Reproduced with permission of Foster et al. (201319. Foster, R. G., S. N. Peirson, K. Wulff, E. Winnebeck, C. Vetter, and T. Roenneberg. 2013. “Sleep and Circadian Rhythm Disruption in Social Jetlag and Mental Illness.” Progress in Molecular Biology and Translational Science 119: 325–346. doi:10.1016/B978-0-12-396971-2.00011-7View all references).
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Arne Duncan, US Secretary of State for Education, tweeted in 2013: ‘let teens sleep, start school later’. This paper examines early starts and their negative consequences in the light of key research in the last 30 years in sleep medicine and circadian neuroscience. An overview of the circadian timing system in adolescence leading to changes in sle...
Citations
... The average age of a JS commencing basic training is 16 yrs., and of the many changes that occur during maturation, changes in the adolescent sleep-wake cycle are among the most dramatic (26)(27)(28). Coinciding with pubertal onset and throughout maturation, adolescents experience a phase delay (i.e., a shift in chronotype preference) in their sleep-wake cycle as reflected by delayed bedtimes, later awakenings and longer sleep periods (27,29,30). These biologically determined adaptations in adolescent sleep-wake patterns dictate a net increase of 0.5-1.25 h, which corresponds to 8.5-9.25 h of required sleep per night, irrespective of adolescent age or maturation stage (17,31). ...
... Poor understanding of the sleep-wake changes and requirements of adolescents combined with chronic and unrecoverable sleep loss risks the presentation of significant health, performance and developmental issues during maturation (29,32). As such, better understanding of the current sleep-wake patterns of JS during training is warranted given the health and performance implications related to poor and unrecoverable sleep loss as demonstrated within civilian populations (30). ...
... However, biological changes in the homeostatic regulation of sleep (i.e., phase delay), which contribute to an increased rise in eveningness-chronotype, leads to extended wakefulness later in the evening (61). Therefore, adolescents will naturally fall asleep ~1-2 h later compared to their adult counterparts (62), which in turn results in later awakenings and demonstrates the futility of earlier bedtimes compared to extended-morning wake/start times on measures of improved physical, behavioral and cognitive function (29,30,63,64). Similar to that of adolescent civilians (30,55), our study has shown that JS are experiencing chronic sleep restriction throughout basic training, mainly from the interaction between biological adaptation (e.g., puberty, circadian and homeostatic adaptations) and environmental constraints (e.g., early basic training start times, poor sleep hygiene, societal pressures/demands), which is likely to lead to persistent and unrecoverable sleep loss. ...
Introduction
Sleep is critical to the health, wellbeing and performance of military personnel during basic training. This two-part study evaluated sleep-wake patterns and sleep disturbances in junior soldiers (JS) and infantry recruits in Autumn 2021 (study 1), and non-infantry recruits in spring 2022 (study 2).
Methods
During studies 1 and 2, validated wearable technology combined with a sleep diary was used to quantify sleep-wake indices, sleep disturbances and perceptions of sleep quality. Sleep diary data was analysed descriptively. A series of repeated-measures ANOVAs examined differences in objective sleep-wake indices. Correlation analysis determined associations between time in bed (TIB) and total sleep time (TST).
Results
Significant (p < 0.05) differences in most sleep-wake indices were observed between weeks of basic training for all cohorts. Strong positive correlations between TIB and TST were observed for each cohort across basic training (r = 0.681 – 0.970, p < 0.001), with longer TST associated with greater TIB. The mean±SD sleep duration (hours and mins [hm]) for JS (06:22 ± 00:27hm), non-infantry (05:41 ± 00:47hm) and infantry (05:46 ± 00:34hm) recruits across basic training was consistently below national recommendations. The mean±SD bed and wake times for JS (bedtime: 23:01 ± 00:32hm; awake: 05:34 ± 00:10hm), non-infantry (bedtime: 23:38 ± 01:09hm; awake: 04:47 ± 00:58hm), and infantry (bedtime: 23:13 ± 00:29hm; awake: 05:38 ± 00:26hm) recruits varied across weeks of basic training, with over 80% reporting “fairly bad” or “very bad” sleep quality and frequent periods of “dozing off” during daytime activity. The most commonly reported sleep disturbing factors identified during basic training involved: late-night military admin (e.g., ironing, boot cleaning, kit set up etc), early morning wake times, extraneous noise, light and hot room temperatures within the primary sleeping environment, bed/mattress discomfort, muscle soreness and feelings of stress and anxiety.
Discussion/Conclusion
Our findings contribute to the existing evidence that long-term sleep loss is pervasive during initial military training programmes. The average sleep durations indicate chronic and unrecoverable sleep loss which would be expected to significantly impair physical and cognitive military performance, and increase the risk of injury, illness and attrition rates during basic training. Changes in the design and scheduling of basic training programmes to enable, at the least, minimum sleep recommendations to be met, and to improve sleep hygiene in the primary sleeping environment are warranted.
... La adaptación a los ciclos circadianos y cronotipos del alumnado demanda una diversificación por edades que hoy en día dista de ser una realidad (Gabaldón-Estevan, 2020a). Es por ello que la necesidad de un replanteamiento de la organización de los horarios escolares, en particular, el retraso del inicio de la jornada escolar no es, ni mucho menos, exclusiva de nuestro país como lo ponen de manifiesto diferentes trabajos (Kelley et al., 2015;Azevedo et al., 2008), pero sí lo es más necesaria en el nuestro en tanto que el huso horario en el que nos forzamos a vivir se encuentra más desincronizado con el horario solar que el de la mayoría de los países de nuestro entorno, y aunque es cierto que socialmente acabamos compensando en buena medida ese desfase en lo que se refiere a las horas de comida y cena, parece que sí tiene un efecto negativo en el arranque de la jornada laboral y escolar y, en consecuencia, en el déficit de sueño y en el desayuno (Gabaldón-Estevan, 2021). ...
... As children transition into adolescence, they typically prefer later sleeping and waking up times (1); this preference conflicts with school start times (SSTs), which usually begins in the early morning (2,3). Conflict with early SST increases the risk of negative health and achievement outcomes, such as poor performance at school, daytime sleepiness, increased moodiness, and increased risk of substance use, including the use of stimulants and alcohol (4)(5)(6)(7)(8). ...
... Thus, while some evidence supports the hypothesis that circadian preferences (chronotypes) are associated with cognitive performance, especially in adolescents, other lines of evidence highlight that sleep patterns of adolescents vary adaptively throughout the week, predominantly through behavior associated with homeostatic regulation (24), and especially during the weekends when youth tend to stay up later (2,16). Accordingly, it is possible that changes in bedtime behavior, rather than chronotypes, could be more of an influencing factor on the differences on cognitive performance during early morning, especially at the beginning of the week, i.e., on Monday, as compared to later in the work/school week (1). ...
... Daylight estimates for March and April were derived from data collected by Environment and Climate Change Canada. 2 The average sunrise for the location and period studied was, in local time, 6 Figure 1, it can be extrapolated that during school days participants went to bed and started sleep on average approximately four hours after sunset and woke up approximately 20 min before sunrise. ...
Introduction
Shorter and/or disrupted sleep during adolescence is associated with cognitive and mental health risks, particularly in females. We explored the relationship between bedtime behavior patterns co-varying with Social Jet Lag (SJL) and School Start Times (SST) and neurocognitive performance in adolescent female students.
Methods
To investigate whether time of day (morning vs. afternoon), early SSTs and days of the school week can be correlated with neurocognitive correlates of sleep insufficiency, we recruited 24 female students aged 16–18 to report sleep logs, and undergo event-related electroencephalographic recordings on Monday, Wednesday, mornings, and afternoons. Using a Stroop task paradigm, we analyzed correlations between reaction times (RTs), accuracy, time of day, day of week, electroencephalographic data, and sleep log data to understand what relationships may exist.
Results
Participants reported a 2-h sleep phase delay and SJL. Stroop interference influenced accuracy on Monday and Wednesday similarly, with better performance in the afternoon. For RTs, the afternoon advantage was much larger on Monday than Wednesday. Midline Event-Related Potentials (ERPs) yielded higher amplitudes and shorter latencies on Wednesday morning and Monday afternoon, in time windows related to attention or response execution. A notable exception were delayed ERP latencies on Wednesday afternoon. The latter could be explained by the fact that delta EEG waves tended to be the most prominent, suggesting heightened error monitoring due to accumulating mental fatigue.
Discussion
These findings provide insights into the interaction between SJL and SST and suggest evidence-based criteria for planning when female adolescents should engage in cognitive-heavy school activities such as tests or exams.
... Time is a fundamental variable in human biology and also in learning (Kelley, Lockley, Foster, & Kelley, 2015). Gettinger and Seibert (2002) suggested that the interest in learners' learning time can be traced back to the 60's. ...
... Rita Dunn et al. (1987) reported time preference was a crucial factor in the reversal of initial and chronic truancy patterns among secondary students. Kelley et al. (2015) found that altering education times can improve learning for adolescence. Moreover, the findings from Kahlaoui (2019) indicated that there is a strong correlation between time of day and students' academic performance for different age groups. ...
... Accordingly, conclusion can't be made in terms of whether learners have preference preferred time to attempt session's assessment when they attend session. Although previous study (Kelley et al., 2015) indicated that time is a key variable in learning related studies, the significant test for hypotheses 1 found that there are no evidence to show learner have preferred time to attempt session's assessment when they attend session. This is possible because of microlearning involves short learning duration time, therefore, when to attempt the assessments are not a concern for learners. ...
This study aims to explore “when would online learners prefer to interact with multimedia microlearning” in higher education context. Although microlearning is an emerging topic, most of the previous studies were focus on reporting the application results of microlearning, only very few of previous works were specifically conducted on discussing when would online learners prefer to interact with multimedia microlearning. An online questionnaire was used to collect learners’ preference on video-based multimedia microlearning. In total, 77 respondents attempted the survey, the response rate is 32.6%. The findings from this study indicate that more learners prefer to study during morning or afternoon rather than evening or midnight time (H2) (p<0.05). On the other hand, there is no significant difference on when to attempt assessment (H1) and on gender issue (H3, H4). To conclude, assessment for microlearning video can be arranged during the video or after the video, learners prefer learning during daytime and gender does not make significance difference on such preferences. The findings from this study generates knowledge to fill the research gap in the field of microlearning. According to the researcher’s best knowledge, this is the first time that a study like this had been conducted to review and discuss the online learners’ preferences on interacting multimedia microlearning. Hopefully, this study could shed some lights on future directions of the development of microlearning.
... Although the previous study (Kelley et al., 2015) indicated that time is a key variable in learning related studies, the significant test for Hypothesis 5 found that there was no evidence to show learners have preferred time to attempt session assessment when they attend sessions. This is possible because microlearning involves short learning duration time; therefore, when to attempt the assessments was not a concern for learners. ...
Purpose
This study aims to explore how learners prefer to interact with microlearning videos. Microlearning is an emerging topic in work-based learning, and the benefits of using video in supporting learning have been widely discussed. However, only very few of previous works were conducted on discussing how learners prefer to interact with microlearning video. This paper aims to fill this knowledge gap.
Design/methodology/approach
A questionnaire was used in this study for data collection purposes. In total, the invitation had been sent to 236 enrolled learners from the 3 targeted modules through emails. A total of 77 participants completed the survey with the response rate 32.6%. The chi-square test is used in this study in order to conclude whether the findings from the sample related to hypotheses are statistically significant.
Findings
By analysing primary data collected from a United Kingdom (UK) university, the findings suggest that 1) the perceived usefulness of the control functions and the expression functions of multimedia microlearning videos are generally high and 2) more participants, on the one hand, prefer to have more control in their multiple-choice questions’ arrangement and open-ended questions’ arrangement; on the other hand, there was no significant difference on the preference of when to attempt assessment.
Originality/value
This is the first time that a study like this had been conducted to review and discuss the interactive preferences between learners and multimedia microlearning. This study could shed some lights on future research in the field of microlearning and work-based learning.
... In the matter of having breakfast, the probability of students staying up late is 0.2 lower than normal students, which is consistent with common sense that students who like to stay up late usually get up late to miss breakfast. For the academic performance, students who go to bed early are more likely to achieve a good grade, which is consistent with previous findings, both in biology [27] and cognitive science [4]. ...
Poor sleep habits may cause serious problems of mind and body, and it is a commonly observed issue for college students due to study workload as well as peer and social influence. Understanding its impact and identifying students with poor sleep habits matters a lot in educational management. Most of the current research is either based on self-reports and questionnaires, suffering from a small sample size and social desirability bias, or the methods used are not suitable for the education system. In this paper, we develop a general data-driven method for identifying students' sleep patterns according to their Internet access pattern stored in the education management system and explore its influence from various aspects. First, we design a Possion-based probabilistic mixture model to cluster students according to the distribution of bedtime and identify students who are used to staying up late. Second, we profile students from five aspects (including eight dimensions) based on campus-behavior data and build Bayesian networks to explore the relationship between behavioral characteristics and sleeping habits. Finally, we test the predictability of sleeping habits. This paper not only contributes to the understanding of student sleep from a cognitive and behavioral perspective but also presents a new approach that provides an effective framework for various educational institutions to detect the sleeping patterns of students.
... Este es, en definitiva, el motivo por el que los adolescentes no se duermen a la hora que la convención social desea. Kelley et al. (2015) publicaron un artículo en el que se explica, con datos procedentes de muy diversas investigaciones, la conveniencia de que las clases de secundaria y de los primeros cursos universitarios -siempre y cuando estén copados por menores de 20 años-empiecen a eso de las diez, diez y media u once de la mañana. Es la misma propuesta que se hace en un estudio realizado en la Universidad de Minnesota. ...
... Fuera del ámbito académico, se ha observado que los conductores adolescentes (en Estados Unidos se pueden conducir coches una vez cumplidos los 16 años) se ven, con relación al resto de grupos de edad, desproporcionalmente más implicados en accidentes durante las horas matinales (Kelley et al. 2015). ...
... Multiple systematic reviews, meta-analyses, and large-scale studies have been published investigating the impact of sleep complaints on mental health and wellbeing in adolescence (Becker, Langberg, & Byars, 2015;Blake, Sheeber, Yousseff, Raniti, & Allen, 2017;Blake, Trinder, & Allen, 2018;Hayes & Bainton, 2020;Hysing, Haugland, Stormark, Boe, & Sivertsen, 2015;Kearns et al., 2020;Kortesoja et al., 2020). Studies have also considered sleep complaints in association with schooling, including school start times, school-night sleep schedules and bedtimes, sleep duration and quality (Beebe, 2011;Crowley et al., 2018;Kelley, Lockley, Foster, & Kelley, 2015;Wheaton, Chapman, & Croft, 2015). Sleep studies involving young people from regional and remote communities at boarding schools are sparse but nevertheless several have investigated: cognitive performance and mood (Lo, Ong, Leong, Gooley, & Chee, 2016); delayed start time and quality of life (Chan, Poon, Leung, Lau, & Lau, 2018); daytime napping (Lau, McAteer, Leung, Tucker, & Li, 2018;Lo et al., 2017); and verbal memory (Huang et al., 2016). ...
... Although further research is required (Bei, Wiley, Trinder, & Manber, 2016;Hayes & Bainton, 2020), considerable intraindividual variability in sleep patterns takes place in adolescence (Magee & Blunden, 2020). Variability in adolescent sleep patterns, particularly between school and non-school nights, but also in connection with sleep complaints like sleep onset, sleep quality and quantity, have been associated with impaired executive functioning, memory and attention (Kelley et al., 2015;Kosticova, Husarova, & Dankulincova, 2020;Kuula et al., 2015), reduced impulse control and behavioural flexibility (Beebe, 2011;Blake et al., 2018), as well as diminished somatic, psychosocial, and mental health (Fuligni, Arruda, Krull, & Gonzales, 2018;Shochat et al., 2014). ...
This exploratory study investigates aspects of sleep quality and some of the potential impacts that sleep complaints for 168 male boarding students from regional and remote communities in Years 7 to 12. An online self-report questionnaire was used to examine the relationship between sleep quality and participants sense of academic self-perception, motivation and regulation, resilience, as well as indicators of non-specific psychological distress, life satisfaction, behavioural and emotional wellbeing. Results found general parity between participants overall scores for sleep quality and norms on the sleep/wake problems scale. However, it emerged that over the previous seven days only a small proportion of participants were satisfied with their sleep every night, with the majority reporting feeling tired or sleepy during the day. This and other findings are discussed in relation to current national sleep recommendations for adolescents, as well as with consideration to the promotion of healthy adolescent development and optimal academic performance, behavioural and cognitive functioning, and emotional regulation. Implications for boarding school routines are discussed with an emphasis on time allocated to sleep, and actual time spent asleep, by adolescent boarders. Strengths and limitations of this study are presented.
... Research shows that raising awareness, reducing depression, and reducing the number of carrelated accidents in adolescents who get enough sleep. A healthy young adult who is exposed to sunlight most of the year sleeps a few hours after sunset and experiences a minimum body temperature of 6 a.m. and wakes up shortly after sunrise (Hagenauer et al. 2009;Carskadon 2011;Kelley et al. 2015). ...
Spices have been added to foods for centuries as flavors, preservatives, and colors and have also been used in traditional medicine in various countries to treat many diseases. Spices play an important role in human health and can be considered as the first functional foods. Although the amount of spices consumed is very low compared to many other foods, the role of spices in the daily diet should not be underestimated due to their health properties. Saffron, ginger, cinnamon, and turmeric are four globally common spices that have been widely used owing to well-known medical benefits in different traditional medicine systems, including Ayurveda, traditional Chinese, and Persian medicine since ancient times. Some general or specific health benefits of these spices include anti-inflammatory, antioxidantAntioxidant, antimicrobial, anti-diabetic, and antihypertensive activities, which have potential protective properties against some ailments such as cancer, type 2 diabetesDiabetes, neurodegenerative and cardiovascular diseases. Recent scientific studies on the therapeutic properties of these common spices have been reviewed in this chapter.
... Research shows that raising awareness, reducing depression, and reducing the number of carrelated accidents in adolescents who get enough sleep. A healthy young adult who is exposed to sunlight most of the year sleeps a few hours after sunset and experiences a minimum body temperature of 6 a.m. and wakes up shortly after sunrise (Hagenauer et al. 2009;Carskadon 2011;Kelley et al. 2015). ...
Nowadays, there is an ever-increasing trend in the case of nutraceuticals and superfoods as a result of growing concerns about the effects of diet on health. Nutraceuticals are natural biologically active compounds extractable from various food sources. In contrast, a superfood is any fresh or processed food claimed to have particular health-promoting attributes and/or can decrease the risk of chronic disease further than its basic nutritionalNutritional function. Different studies have shown that the nutraceuticals and superfoods have various beneficial physiological effects, and their consumption can reduce the risk for disease development or can even cure some diseases because they are rich sources of a wide range of bioactiveBioactive molecules and specific nutrients. Some examples of nutraceuticals and superfoods are curcumin, pomegranate, camel milk, bioactive peptides, and walnut, which their potential health benefits and applications for the development of functional foodFunctional food products with health-promoting properties have been studied in the present chapter.
