Children's mental health is affected by sleep duration
February 4, 2020
Science Daily/University of Warwick
Depression, anxiety, impulsive behaviour and poor cognitive performance in children is affected by the amount of sleep they have, researchers from the University of Warwick have found.
Sleep states are active processes that support reorganisation of brain circuitry. This makes sleep especially important for children, whose brains are developing and reorganizing rapidly.
In the paper 'Sleep duration, brain structure, and psychiatric and cognitive problems in children,' published in the journal Molecular Psychiatry, 11,000 children aged 9-11 from the Adolescent Brain Cognitive Development dataset had the relationship between sleep duration and brain structure examined by researchers Professor Jianfeng Feng, Professor Edmund Rolls, Dr. Wei Cheng and colleagues from the University of Warwick's Department of Computer Science and Fudan University.
Measures of depression, anxiety, impulsive behaviour and poor cognitive performance in the children were associated with shorter sleep duration. Moreover, the depressive problems were associated with short sleep duration one year later.
Lower brain volume of brain areas involved the orbitofrontal cortex, prefrontal and temporal cortex, precuneus, and supramarginal gyrus was found to be associated with the shorter sleep duration by using big data analysis approach.
Professor Jianfeng Feng, from the University of Warwick's Department of Computer Science comments:
"The recommended amount of sleep for children 6 to 12 years of age is 9-12 hours. However, sleep disturbances are common among children and adolescents around the world due to the increasing demand on their time from school, increased screen time use, and sports and social activities.
A previous study showed that about 60% of adolescents in the United States receive less than eight hours of sleep on school nights.
"Our findings showed that the behaviour problems total score for children with less than 7 hours sleep was 53% higher on average and the cognitive total score was 7.8% lower on average than for children with 9-11 hours of sleep. It highlights the importance of enough sleep in both cognition and mental health in children."
Professor Edmund Rolls from the University of Warwick's Department of Computer Science also commented:
"These are important associations that have been identified between sleep duration in children, brain structure, and cognitive and mental health measures, but further research is needed to discover the underlying reasons for these relationships."
https://www.sciencedaily.com/releases/2020/02/200204094726.htm
Chronobiology: 'We'll be in later'
December 20, 2019
Science Daily/Ludwig-Maximilians-Universität München
Students attending a high school in Germany can decide whether to begin the schoolday at the normal early time or an hour later. According to Ludwig-Maximilians-Universitaet (LMU) in Munich chronobiologists, the measure has had a positive effect on both their sleep and learning experience.
They fall asleep too late at night, and are rudely expelled from dreamland by the shrill tones of the alarm clock in the morning. Classes begin early and they must be prepared to show their mettle.
Adolescents are constantly sleep deprived, a phenomenon that can be observed worldwide. In addition, the problem is no longer confined to certain personality types and therefore of individual concern, it has become a public health issue. Indeed, the Centers for Disease Control and Prevention in the US have officially designated the matter as a public health concern. The consequences of chronic sleep deficit include not only a reduced ability to concentrate but also an increased accident risk to and from school. Studies have also detected higher risks for depression, obesity, diabetes and other chronic metabolic diseases. In light of these findings, it is hardly surprising that calls for school classes to begin later in the morning are becoming louder.
But would such a move do any good? Would a later school start actually change the sleep of adolescents for the better, and enhance their cognitive performance in class? So far, there have been few research studies of this question in Europe. A group of chronobiologists in Munich, led by Eva Winnebeck and Till Roenneberg, studied the issue at a high school in Germany that made an exceptional change to their starting time arrangement. This school instituted a system that allows senior students to decide day by day whether or not to attend the first class of the day or to come to school an hour later. This form of flexible scheduling is possible because the school has adopted what is known as the Dalton Plan (for which the institution won the German School Prize in 2013). A major component of this idea (which originated in the US) is that students are required to tackle parts of the school curriculum independently in the context of project phases. The school timetable allots 10 hours per week for these activities, half of which are scheduled for the first class at 8 o'clock in the morning. Students who choose to skip this class must work through the material in their free periods during the day or after the end of the regular school day. Students from the three senior grades (i.e. 15- to 19-year-olds) served as the study population for LMU researchers from the Institute of Medical Psychology. For 3 weeks before and 6 weeks after the introduction of the flexible system in the school in Alsdorf, the team observed how the students reacted and adapted to the change. The participating students were asked to record their sleeping patterns daily, and around half of them were equipped with activity monitors for objective sleep monitoring. At the end of the study, the participants provided information on their sleep, their overall level of satisfaction and their ability to concentrate in class and while studying course content.
The team was initially surprised by the fact that the students made relatively little use of the new-found freedom to start school later, says Eva Winnebeck. On average, they chose to miss out on the first class twice a week. On these days, they slept more than an hour longer than usual, irrespective of gender, grade, chronotype or frequency of later school starts. In other words, nearly all of the students involved in the project benefited when going later. In contrast to the era of rigid school start times, however, the switch to flexible starts did not result in a significant increase in the overall duration of students' sleep. Nevertheless, the students were very satisfied with the new scheduling model. The vast majority of students reported that they slept better and were better able to focus on the course material in school. "Perhaps the very fact that one can decide for oneself when to get up in the morning is sufficient to break the cycle and reduce the pressure," says Winnebeck. According to the authors of the study, which appears in the journal Sleep, "flexible systems are a viable alternative for implementing later school starts to improve teenage sleep." But they also underline the importance of actively encouraging students to make use of the option to start the school day later.
https://www.sciencedaily.com/releases/2019/12/191220150600.htm
School-based sleep program may benefit adolescents
November 6, 2019
Science Daily/Wiley
A recent study uncovered potential long-term benefits of a school-based sleep education program for adolescents.
The study, which was published in the Journal of Sleep Research, included 3,622 adolescents, 286 in the intervention group and 3336 in the control group. Data were collected before the intervention and at a one-year follow-up.
The intervention consisted of five sessions, 50-60 minutes, once per week for six to seven weeks and was scheduled as part of students' school curriculum. Investigators divided participants into three groups according to baseline sleep duration: insufficient (less than seven hours), borderline (seven to eight hours) and adequate (more than eight hours). Adolescents in the intervention group were approximately two times less likely to report insufficient sleep at follow-up compared with controls. Sleep knowledge improved significantly in the intervention group but there were no changes in emotional sleep hygiene (such as bedtime worry) and perceived stress. Surprisingly, technology use increased and behavioral sleep hygiene worsened (for example, performing activities in bed that keep you awake) in the intervention group.
"These results are promising and mean that we might be able to prevent the development of sleep problems in youths," said lead author Serena V. Bauducco, PhD, of Örebro University, in Sweden. "More work needs to be done, however: we need to replicate these results and to understand what works. Therefore, we encourage future sleep intervention studies to investigate long-term outcomes -- after one year or even longer -- and to look for mechanisms of change."
https://www.sciencedaily.com/releases/2019/11/191106085433.htm
Split and continuous sleep in teens impact cognition and glucose levels differently
February 22, 2019
Science Daily/Duke-NUS Medical School
Under conditions of insufficient sleep, effects on cognitive performance and morning glucose levels vary depending on how sleep is distributed.
Many adolescent students sleep less than the recommended duration of 8-10 hours a night. It is unclear; however, whether short night sleep combined with an afternoon nap is as good as having the same amount of sleep continuously during the night without a nap. Researchers at Duke-NUS Medical School have demonstrated for the first time that different sleep schedules with the same total sleep opportunity over 24 hours may have dissimilar effects on cognition and glucose levels. This is the first study to gather experimental evidence on the notion that 'what may be appropriate sleep for one health goal may not be for another'.
The handful of studies that examined split sleep schedules with normal total sleep duration in working-age adults found that both schedules yield comparable brain performance. However, no study has looked at the impact of such schedules on brain function and glucose levels together, especially when total sleep is shorter than optimal. The latter is important because of links between short sleep and risk for diabetes.
The researchers measured cognitive performance and glucose levels following a standardized load in students, aged 15-19 years, during two simulated school weeks with short sleep on school days and recovery sleep on weekends. On school days, these students received either continuous sleep of 6.5 hours at night or split sleep (night sleep of 5 hours plus a 1.5-hour afternoon nap).
"We undertook this study after students who were advised on good sleep habits asked if they could split up their sleep across the day and night, instead of having a main sleep period at night," said Prof. Michael Chee, Director of the Centre for Cognitive Neuroscience, Professor of Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School and one of the study's senior authors. "We found that compared to being able to sleep 9 hours a night, having only 6.5 hours to sleep in 24 hours degrades performance and mood. Interestingly, under conditions of sleep restriction, students in the split sleep group exhibited better alertness, vigilance, working memory and mood than their counterparts who slept 6.5 hours continuously. This finding is remarkable as the measured total sleep duration over 24 hours was actually less in the former group," Prof. Chee added.
However, for glucose tolerance, the continuous schedule appeared to be better. "While 6.5 hours of night sleep did not affect glucose levels, the split sleep group demonstrated a greater increase in blood glucose levels to the standardized glucose load in both simulated school weeks," noted Dr. Joshua Gooley, Associate Professor of Neuroscience and Behavioral Disorders Programme, Principal Investigator at the Centre for Cognitive Neuroscience, Duke-NUS Medical School and the senior co-author of this study.
Although further studies are necessary to see if this finding translates to a higher risk of diabetes later in life, the current findings indicate that beyond sleep duration, different sleep schedules can affect different facets of health and function in directions that are not immediately clear.
Professor Patrick Casey, Senior Vice Dean of Research, Duke-NUS Medical School, commented, "Recent sleep surveys show that Singaporeans are among the world's most sleep deprived people. This is the latest in a series of studies from a team of researchers from the Neuroscience and Behavioural Disorders Programme and Centre for Cognitive Neuroscience that have provided valuable insights into the importance of good sleep."
https://www.sciencedaily.com/releases/2019/02/190222101312.htm
Blue Light Could Help Teenagers Combat Stress
October 22, 2012
Science Daily/Rensselaer Polytechnic Institute (RPI)
A new study shows that exposure to morning short-wavelength “blue” light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light.
Adolescents can be chronically sleep deprived because of their inability to fall asleep early in combination with fixed wakeup times on school days. According to the CDC, almost 70 percent of school children get insufficient sleep -- less than 8 hours on school nights. This type of restricted sleep schedule has been linked with depression, behavior problems, poor performance at school, drug use, and automobile accidents.
A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that exposure to morning short-wavelength "blue" light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light.
Levels of cortisol, a hormone produced by the adrenal gland, follow a daily 24-hour rhythm. Cortisol concentrations are low throughout the day reaching a broad minimum in the evening before rising slowly again throughout the night. In addition to this gradual elevation of cortisol at night, cortisol levels rise sharply within the first 30 to 60 minutes after waking.
This is known as the cortisol awakening response (CAR). In nocturnal animals, the cortisol spike occurs at night, at the start of activity. It appears to be associated with the time of transition from rest to activity, upon waking. A high CAR has been associated with better preparedness for stressful and challenging activities.
"The present results are the first to show that low levels of short-wavelength light enhance CAR in adolescents who were restricted from sleep," said Figueiro. "Morning light exposure may help to wake up the body when it is time to be active, thus preparing individuals for any environmental stress they might experience."
Short-wavelength light has been shown to maximally suppress production of nocturnal melatonin and phase shift the timing of the biological clock. The effect of short-wavelength light on other biomarkers has not been widely studied.
The study included three overnight sessions, at least one week apart. All participants wore a Dimesimeter on a wrist band to measure light exposure and to verify the regularity of their activity/rest periods during the three-week study. The Dimesimeter is a small calibrated light meter device developed by the LRC that continuously records circadian light and activity levels.
During the study, adolescents aged 12 to 17 years went to sleep at 1:30 a.m. and woke up at 6:00 a.m., a 4.5-hour sleep opportunity. Each week, participants either experienced morning short-wavelength blue light (40 lux of 470-nanometer light) or remained in dim light.
http://www.sciencedaily.com/releases/2012/10/121022112847.htm