Reading from an iPad or from a book in bed: the impact on human sleep. A randomized controlled crossover trial

Multimodal population study reveals the neurobiological underpinnings of chronotype

The rapid shifts in society have altered human behavioural patterns, with increased evening activities, increased screen time and changed sleep schedules. As an explicit manifestation of circadian rhythms, chronotype is closely intertwined with physical and mental health. Night owls often exhibit unhealthier lifestyle habits, are more susceptible to mood disorders and have poorer physical fitness compared with early risers. Although individual differences in chronotype yield varying consequences, their neurobiological underpinnings remain elusive. Here we conducted a pattern-learning analysis with three brain-imaging modalities (grey matter volume, white-matter integrity and functional connectivity) and capitalized on 976 phenotypes in 27,030 UK Biobank participants. The resulting multilevel analysis reveals convergence on the basal ganglia, limbic system, hippocampus and cerebellum. The pattern derived from modelling actigraphy wearables data of daily movement further highlighted these key brain features. Overall, our population-level study comprehensively investigates chronotype, emphasizing its close connections with habit formation, reward processing and emotional regulation.

Scoping review of the measurement of care environment factors that impact sleep in the rehabilitation, subacute, and aged care settings

Study Objectives

Unfamiliar environments are often poorly conducive to quality sleep, especially for patients within health and aged care settings. This scoping review aims to map available evidence regarding the sleep environment in rehabilitation, subacute, and aged care settings. It examines how these factors are measured and seeks to identify any reported standard metrics, guidelines, or methodologies.

Methods

Searches were conducted within PubMed, EMBASE, Cochrane Library, Cumulated Index to Nursing and Allied Health Literature, PsycINFO, and Web of Science from database inception to May 2023. Eligibility criteria included original studies of any design reporting on the measurement properties of care environment factors affecting the sleep of adult patients admitted to rehabilitation, subacute wards, and aged care facilities.

Results

Seventy-four studies were reviewed that included 5055 participants, mostly (78.4%, 58/74) from aged care facilities. From 102 identified care environment factors, the spectral measurements of light were most reported (65.7%, 67/102), with methodologies varying from actigraphy and illuminance meters to pendant-style light monitors. Other environmental factors (sound, temperature, and air quality/humidity), room characteristics (mattress/bedding, room cohabitation), and hospital functioning (imposed schedules) were measured considerably less often and displayed similar variations in reported units and devices. Eighteen studies reported international, national, and methodological standards or guidelines.

Conclusions

This review provides a comprehensive overview of the care environment factors affecting sleep studied within rehabilitation, subacute, and aged care settings. Various units and devices were used in measuring these factors, and standard metrics and methodology were not consistently used. Future care environment studies incorporating interventions that employ standardized devices, units, and methodologies, will thereby enhance the reliability and comparability of findings within this field.

Social Media and Sleep Health

Social media interferes with pediatric sleep health with downstream consequences for mental health and other developmental outcomes. Based on the literature on screen use and sleep, social media likely affects sleep through the following proposed mechanisms: activity displacement, content-related arousal, alerting effects of light, and disruptions from noises and vibrations. Future research on this topic should improve measurement of both social media use and sleep health. Scalable, sustainable, and effective interventions should be developed and evaluated. We offer clinical recommendations for reducing the negative effects of social media on pediatric sleep health.

The relationship between chronotype characteristics and fear of missing out, phubbing, sleep quality and social jetlag in medical students

Chronotype is the temporal behavior of an organism. Social jetlag, fear of missing out (FoMO), and phubbing have received increasing attention recently and are closely related to sleep quality. This study aimed to explore the relationship between chronotype and these factors and their effects on sleep quality among medical students. The FoMO scale, phubbing behavior assessment scale, morning-evening questionnaire, Pittsburgh sleep quality index, social jetlag questionnaire, and online sociodemographic data form were filled out by 537 students participating in the study. The average age of participants was 21.34 ± 1.38 years; 43.2% were male, and 56.8% were female. The majority (66.7%) had an intermediate chronotype, 20.9% an evening type, and 12.5% a morning type. Evening chronotypes exhibited the highest levels of social jetlag, daily internet/phone use, and the poorest sleep quality and daily functioning. Women reported significantly higher levels of FoMO (p < 0.001), phubbing (p = 0.020), and daytime dysfunction (p = 0.005). Multiple regression analysis showed poor sleep quality was associated with high FoMO, high phubbing, high levels of social jetlag, and evening chronotype. Additionally, daytime dysfunction was associated with female gender, poor sleep quality, high FoMO, and high levels of phubbing (p < 0.001, F = 16.128, R2 = 0.221). These results suggest that individuals with an evening type may be susceptible to social interaction, social media use, and sleep patterns, which may negatively affect sleep quality. It has also been determined that females may be at greater risk for FoMO and phubbing. Evaluation of individuals' chronotypes will be an essential step in treating behavioral addictions such as social media, screen, and smartphone addiction.

The impact of screen use on sleep health across the lifespan: A National Sleep Foundation consensus statement

OBJECTIVE

To achieve consensus on whether screen-based digital media (1) in general, (2) via prebedtime content, and (3) via prebedtime light impairs sleep health in (a) childhood, (b) adolescence, and (c) adulthood. Furthermore, to address whether employing behavioral strategies and interventions may reduce the potential negative effects of screens on sleep health.

METHODS

The National Sleep Foundation convened a 16-person multidisciplinary expert panel ("Panel"). Panelists met virtually 5 times throughout 2023, during which they followed a modified Delphi RAND/UCLA Appropriateness Method to reach consensus.

RESULTS

The Panel conducted a literature review starting with 2209 articles, narrowed down to 522 relevant empirical articles and 52 relevant review articles. The search was refined to include 35 experimental/intervention studies that examined whether there was a causal link between screen-based digital media and sleep. In addition, panelists reviewed 5 recent relevant systematic review articles. After reviewing the summarized current literature, panelists voted on 10 candidate statements about whether screen use impairs sleep health. The Panel met virtually to discuss the results of the first round of votes, which was then followed by a second round of voting, ultimately achieving consensus on 5 out of the 10 statements.

CONCLUSIONS

The Panel achieved consensus that (1) in general, screen use impairs sleep health among children and adolescents, (2) the content of screen use before sleep impairs sleep health of children and adolescents, and (3) behavioral strategies and interventions may attenuate the negative effects of screen use on sleep health.

A bidirectional model of sleep and technology use: A theoretical review of How much, for whom, and which mechanisms

The link between technology and sleep is more complex than originally thought. In this updated theoretical review, we propose a new model informed by the growing body of evidence in the area over the past 10 years. The main theoretical change is the addition of bi-directional links between the use of technology and sleep problems. We begin by reviewing the evidence to date for the originally proposed mechanisms of bright light, arousal, nighttime sleep disruptions, and sleep displacement. Then, in support of the new direction of effect (sleep problems preceding technology use), we propose two new mechanisms: technology before sleep might be used as a time filler and/or as an emotional regulation strategy to facilitate the sleep-onset process. Finally, we present potential moderators of the association between technology and sleep, in recognition of protective and vulnerability factors that may mitigate or exacerbate the effects of technology on sleep and vice versa. The goal of this theoretical review is to update the field, guide future public health messages, and to prompt new research into how much technology and sleep affect each other, for whom it may be problematic, and which mechanisms may explain their association.

Time use and dimensions of healthy sleep: A cross-sectional study of Australian children and adults

BACKGROUND

Sleep is increasingly recognized as a multidimensional construct that occurs within the 24-hour day. Despite advances in our understanding, studies continue to consider the relationship between sleep, sedentary time and physical activity separately, and not as part of the 24-hour day.

AIMS

To determine the association between the 24-hour activity composition and dimensions of healthy sleep.

METHODS

This study examined data on 1168 children (mean age 12years; 49% female) and 1360 adults (mean age 44years; 87% female) collected as part of the Child Health CheckPoint study. Participants were asked to wear a GENEActiv monitor (Activinsights, Cambs, UK) on their nondominant wrist for eight consecutive days to measure 24-hour time-use. Compositional data analysis was used to examine the association between time use (actigraphy-derived sleep duration, sedentary time, light physical activity and moderate-vigorous physical activity) and dimensions of healthy sleep. Healthy sleep was conceptualized in terms of continuity/efficiency, timing, alertness/sleepiness, satisfaction/quality, and regularity. Time allocations were also examined.

RESULTS

The 24-hour activity composition was significantly associated with all objectively measured and self-report dimensions of healthy sleep in both children and adults. Allocating more time to sleep was associated with earlier sleep onsets, later sleep offsets, less efficient and more consistent sleep patterns for both children and adults.

CONCLUSION

This study highlights the integral relationship between daily activities and dimensions of sleep. Considering sleep within the 24-hour day activity composition framework may help inform lifestyle decisions to improve sleep health.

Sleep hygiene - What do we mean? A bibliographic review

There is no consensus on the definition of sleep hygiene and its components. We examined the definition of sleep hygiene based on its use in published studies. Four databases (Medline, EMBASE, PsycINFO and CINAHL) were searched from inception until December 31, 2021 for the phrase 'sleep hygiene' in the title or abstract. We identified 548 relevant studies in adults: 250 observational and 298 intervention studies. A definition of sleep hygiene was provided in only 44% of studies and converged on three themes: behavioural factors, environmental factors, and an aspect of control. Sleep hygiene components were explicitly defined in up to 70% of observational studies, but in only 35% of intervention studies. The most commonly considered components of sleep hygiene were caffeine (in 51% of studies), alcohol (46%), exercise (46%), sleep timing (45%), light (42%), napping (39%), smoking (38%), noise (37%), temperature (34%), wind-down routine (33%), stress (32%), and stimulus control (32%), although the specific details of each component varied. Lack of consistency in definitions of sleep hygiene and its components may hinder communication between researchers, clinicians, and the public, and likely limits the utility of sleep hygiene as an intervention.

Effects of evening smartphone use on sleep and declarative memory consolidation in male adolescents and young adults

Exposure to short-wavelength light before bedtime is known to disrupt nocturnal melatonin secretion and can impair subsequent sleep. However, while it has been demonstrated that older adults are less affected by short-wavelength light, there is limited research exploring differences between adolescents and young adults. Furthermore, it remains unclear whether the effects of evening short-wavelength light on sleep architecture extend to sleep-related processes, such as declarative memory consolidation. Here, we recorded polysomnography from 33 male adolescents (15.42 ± 0.97 years) and 35 male young adults (21.51 ± 2.06 years) in a within-subject design during three different nights to investigate the impact of reading for 90 min either on a smartphone with or without a blue-light filter or from a printed book. We measured subjective sleepiness, melatonin secretion, sleep physiology and sleep-dependent memory consolidation. While subjective sleepiness remained unaffected, we observed a significant melatonin attenuation effect in both age groups immediately after reading on the smartphone without a blue-light filter. Interestingly, adolescents fully recovered from the melatonin attenuation in the following 50 min before bedtime, whereas adults still, at bedtime, exhibited significantly reduced melatonin levels. Sleep-dependent memory consolidation and the coupling between sleep spindles and slow oscillations were not affected by short-wavelength light in both age groups. Nevertheless, adults showed a reduction in N3 sleep during the first night quarter. In summary, avoiding smartphone use in the last hour before bedtime is advisable for adolescents and young adults to prevent sleep disturbances. Our research empirically supports general sleep hygiene advice and can inform future recommendations regarding the use of smartphones and other screen-based devices before bedtime.

Photoperiod and metabolic health: evidence, mechanism, and implications

Circadian rhythms are evolutionarily programmed biological rhythms that are primarily entrained by the light cycle. Disruption of circadian rhythms is an important risk factor for several metabolic disorders. Photoperiod is defined as total duration of light exposure in a day. With the extended use of indoor/outdoor light, smartphones, television, computers, and social jetlag people are exposed to excessive artificial light at night increasing their photoperiod. Importantly long photoperiod is not limited to any geographical region, season, age, or socioeconomic group, it is pervasive. Long photoperiod is an established disrupter of the circadian rhythm and can induce a range of chronic health conditions including adiposity, altered hormonal signaling and metabolism, premature ageing, and poor psychological health. This review discusses the impact of exposure to long photoperiod on circadian rhythms, metabolic and mental health, hormonal signaling, and ageing and provides a perspective on possible preventive and therapeutic approaches for this pervasive challenge.

What's your religious coping profile? Differences in religious orientation and subjective sleep among religious coping groups in the United States

OBJECTIVES

To determine various profiles/subgroups of religious copers based on indices of positive and negative religious coping; and to determine whether religious copers differ in their religious orientations, subjective sleep characteristics, and strategies used to cope with sleep problems.

METHOD

Six hundred and ninety-five adults (77.3% female, 70.4% White) in the United States completed a 20-minute online questionnaire in January 2020.

RESULTS

Results of a latent profile analysis, based on 8 indicators of positive and negative religious coping, indicated a 5-class solution: (i) "Absent" (n = 101, 14.5%); (ii) "Anxious" (n = 122, 17.6%); (iii) "Ambivalent" (n = 101, 14.5%); (iv) "Secure" (n = 200, 28.8%); and (v) "Conflicted" copers (n = 171, 24.6%). Results of MANOVA tests indicated that Secure copers reported the least religious doubt and highest religious-based social support. Conflicted and Anxious copers had the worst sleep quality, while Secure, Ambivalent, and Absent copers had healthier sleep profiles. In terms of strategies used to cope with sleep problems, Secure and Conflicted copers reported the greatest use of prayer and meditation, while the use of technology was most prevalent among Conflicted and Anxious copers.

CONCLUSIONS

Individuals differ in their combined use of positive and negative religious coping, which is related to differences in their religious orientation, sleep characteristics, and strategies used to cope with sleep problems. Religious leaders should be mindful of the diverse ways in which religious coping strategies are harnessed to effectively cater to the unique religious and sleep needs of their members.

Sleep Quality and Perceived Stress among Health Science Students during Online Education-A Single Institution Study

Recently, online education has been gaining prominence in university life. Our survey aimed to examine sleep quality and perceived stress levels among students at the University of Pécs Faculty of Health Sciences. A cross-sectional, quantitative, descriptive survey was conducted between February and March 2023. The online survey included the Hungarian versions of the internationally validated Athens Insomnia Scale (AIS) and Perceived Stress Scale (PSS). Statistical analysis involved descriptive statistics, independent t-tests, analysis of variance (ANOVA), and Mann-Whitney and Kruskal-Wallis tests (p < 0.05). We analyzed 304 responses, and females dominated (n = 270; 88.8%). Students in a relationship had significantly higher AIS scores (t = -2.470; p = 0.014). Medium average (2.50-3.49) students and those who rarely/never exercise showed significantly higher AIS and PSS (p ≤ 0.05). Students on the phone/watching a series during online education, daily laptop/TV use for more than 2 h, and pre-sleep use of smart devices for more than 60 min also negatively affected AIS and PSS scores (p ≤ 0.05). Nursing, physiotherapy, and radiography students were the most affected regarding insomnia and perceived stress (p ≤ 0.05). Our survey shows that excessive smart device use and lack of exercise are associated with higher stress levels and poorer sleep quality.

Association of smartphone use with abnormal social jetlag among adolescents in Korea before and after COVID-19

PURPOSE

This study aimed to use social jetlag to determine how smartphone overuse by adolescents before and after the COVID-19 pandemic might be associated with their circadian rhythm.

METHODS

We used 2017 and 2020 Korea Youth Risk Behavior web-based Survey data and conducted a survey analysis on 100,976 adolescents. The dependent variable was abnormal social jetlag. Based on the times recorded by the survey, we calculated the weekday midpoint and weekend sleep time. The main independent variable was smartphone usage time (<2h/day, 2-3.9 h/day, 4-5.9 h/day, and ≥ 6 h/day). Multiple logistic regression and relative excess risk due to interaction (RERI) were performed.

RESULTS

Abnormal social jetlag was most prevalent in male and female adolescents who used smartphones ≥ 6 h/day (adjusted odds ratio [AOR] = 2.60, 95 % confidence interval [CI] = 2.47-2.74). The longer the smartphone usage time, the higher the association with abnormal social jetlag. This association was more prominent in female adolescents. The additive interaction between longer smartphone usage time and post-COVID-19 year was statistically significant (total: RERI = 0.92, 95 % CI = 0.90-0.95; males: RERI = 0.83, 95 % CI = 0.80-0.87; females: RERI = 1.13, 95 % CI = 1.08-1.18).

CONCLUSION

Our results clearly indicated that increased smartphone usage time tended to result in greater social jetlag, an association that was more pronounced in female. Moreover, the COVID-19 pandemic significantly strengthened this relationship. Further research is needed regarding the proper use of smartphones to ensure good sleep-in adolescents after the COVID-19 pandemic.

Wireless EEG: A survey of systems and studies

The popular brain monitoring method of electroencephalography (EEG) has seen a surge in commercial attention in recent years, focusing mostly on hardware miniaturization. This has led to a varied landscape of portable EEG devices with wireless capability, allowing them to be used by relatively unconstrained users in real-life conditions outside of the laboratory. The wide availability and relative affordability of these devices provide a low entry threshold for newcomers to the field of EEG research. The large device variety and the at times opaque communication from their manufacturers, however, can make it difficult to obtain an overview of this hardware landscape. Similarly, given the breadth of existing (wireless) EEG knowledge and research, it can be challenging to get started with novel ideas. Therefore, this paper first provides a list of 48 wireless EEG devices along with a number of important-sometimes difficult-to-obtain-features and characteristics to enable their side-by-side comparison, along with a brief introduction to each of these aspects and how they may influence one's decision. Secondly, we have surveyed previous literature and focused on 110 high-impact journal publications making use of wireless EEG, which we categorized by application and analyzed for device used, number of channels, sample size, and participant mobility. Together, these provide a basis for informed decision making with respect to hardware and experimental precedents when considering new, wireless EEG devices and research. At the same time, this paper provides background material and commentary about pitfalls and caveats regarding this increasingly accessible line of research.

Digital media use and sleep in late adolescence and young adulthood: A systematic review

Despite much attention on digital media use and young peoples' sleep, the literature on digital media and its impact on sleep in older adolescents and young adults remains to be synthesized. We conducted a systematic review of studies including young people aged 16-25 years. We searched Medline, Web of Science, and CINAHL for observational studies, identifying 60 studies. These studies were assessed for methodological quality. Only studies rated as moderate or high-quality studies were included (n = 42). A narrative synthesis summarized the impact of digital media use on eight sleep outcomes: Bedtime; Sleep onset latency or problems falling asleep; Sleep duration; Early awakening; Sleep disturbance; Daytime tiredness and function; Sleep deficits; Sleep quality. In summary, digital media use was associated to shorter sleep duration and poorer sleep quality. These associations were found for general screen use and use of mobile phone, computer, internet, and social media, but not for television, game console, and tablet use. Most studies investigating bedtime or nighttime use found associations to poor sleep outcomes. Later bedtime and daytime tiredness were associated with mobile phone use at night. Additional research is warranted to draw solid conclusions about the causal direction and to understand the underlying mechanisms.

Do both timing and duration of screen use affect sleep patterns in adolescents?

BACKGROUND

Sleep duration has declined in adolescents over the last 30 years and screen use has been identified as a risk factor. Studies have examined the duration of screen use and screen-based activities but have not differentiated between evening and night-time use.

METHODS

Cross sectional questionnaire survey of adolescents recruited in schools. Sleep habits on school nights and weekends, symptoms of insomnia and daytime repercussions were recorded using an online questionnaire administered in the classroom setting. Sleep deprivation (<7 hours in bed /night), school night sleep restriction (≥2 hours difference in sleep duration on school nights vs weekends), excessive sleepiness (score >6 on a visual analogue scale), duration of screen use and timing of screen use (evening vs after bedtime) were determined.

RESULTS

2513 students (53.4% female, median age 15 years) were included. 20% were sleep deprived and 41% sleep restricted. A clear dose effect relationship in a model controlling for age, sex, school level and sociodemographic class was seen with all levels of night-time screen use on sleep deprivation and sleep restriction (>2 hours use sleep deprivation OR 5.23[3.03-9.00]. sleep restriction OR 2.05[1.23-3.42]) and > 2 hours evening use (>2 hours use sleep deprivation OR 2.72[2.15-3.44] sleep restriction OR 1.69[1.36-2.11]) but not moderate evening use. All night-time use and > 2 hours evening use increased the risk of insomnia, non refreshing sleep, and affected daytime function (daytime sleepiness, lack of energy and irritability).

CONCLUSIONS

Both duration of screen use and timing are associated with adverse effects on sleep and daytime functioning in adolescents. More than 2 hours evening use and all night-time use should be avoided.

The influence of blue light on sleep, performance and wellbeing in young adults: A systematic review

Introduction: Blue light from electronic devices has a bad reputation. It has a wavelength which may influence our circadian rhythm and cause bad sleep. But there are other aspects of blue light exposure which are often overlooked, for example, it may influence performance and wellbeing. However, few resources summarize its effects systematically. Therefore, the goal of this systematic review was to distil the present evidence on blue light exposure and its influence on sleep, performance and wellbeing and discuss its significance for athletes.

Methods: The databases that were searched were Cochrane, Embase, Pubmed, Scopus, and Virtual Health Library. The studies included investigated the influence of blue light exposure on either sleep, performance, wellbeing or a combination of those parameters on healthy humans. Quality assessment was done based on the quantitative assessment tool “QualSyst.”

Results: Summarizing the influence of blue light exposure, the following results were found (expressed as proportion to the number of studies investigating the particular parameter): Fifty percent of studies found tiredness to be decreased. One fifth of studies found sleep quality to be decreased and one third found sleep duration to be decreased. Half of the studies found sleep efficacy to be decreased and slightly less than half found sleep latency to be increased. More than one half of the studies found cognitive performance to be increased. Slightly more than two thirds found alertness to be increased and reaction time to be decreased. Slightly less than half of the studies found wellbeing to be increased.

Conclusion: Blue light exposure can positively affect cognitive performance, alertness, and reaction time. This might benefit sports reliant on team-work and decision-making and may help prevent injury. Blue light might also have negative effects such as the decrease in sleep quality and sleep duration, which might worsen an athlete’s physical and cognitive performance and recovery. Further research should explore if blue light can improve sleep, performance and wellbeing to significantly benefit athletic performance.

Effects of Limiting Recreational Screen Media Use on Physical Activity and Sleep in Families With Children: A Cluster Randomized Clinical Trial

IMPORTANCE

Children and adults spend large amounts of their leisure time using screen media, which may affect their health and behavior.

OBJECTIVE

To investigate the effect of reducing household recreational screen media use on physical activity and sleep in children and adults.

DESIGN, SETTING, AND PARTICIPANTS

This was a cluster randomized clinical trial with a 2-week follow-up. Enrollment began on June 6, 2019, and ended on March 30, 2021. This study included a population-based sample from 10 Danish municipalities. A total of 89 families (181 children and 164 adults) were recruited based on a population-based survey on screen media habits in families with children. To be eligible, the responding parent had to list self-reported recreational screen use greater than the 40th percentile of recreational screen time use in the source population (>2.4 hours per day). In addition, the parent had to be full-time employed (with no regular night shifts) or enrolled in full-time education.

INTERVENTIONS

Families were randomly assigned to the screen media reduction intervention (45 families, 86 children, 82 adults) designed to ensure participant compliance to a maximum use of screen media (≤3 hours per week) for a 2-week period. Families randomly assigned to the control group (44 families, 95 children, 82 adults) were instructed to carry on as usual.

MAIN OUTCOMES AND MEASURES

The primary outcome was between-group difference in leisure nonsedentary activity (in minutes per day) measured by combined thigh and waist accelerometry. Secondary outcomes included other physical activity and sleep parameters measured by single-channel electroencephalography.

RESULTS

Among the 89 randomized families (intervention group [45 families]: 86 children; mean [SD] age, 8.6 [2.7] years; 44 boys [51%]; 42 girls [49%]; control group [44 families]: 95 children, mean [SD] age, 9.5 [2.5] years; 38 boys [40%]; 57 girls [60%]), 157 children (87%) had complete data on the primary outcome. Eighty-three children (97%) in the intervention group were compliant to the screen use reduction during the intervention. The mean (SD) change in leisure nonsedentary activity in the intervention group was 44.8 (63.5) minutes per day and in the control group was 1.0 (55.1) minute per day (intention-to-treat between-group mean difference, 45.8 minutes per day; 95% CI, 27.9-63.6 minutes per day; P < .001). No significant between-group mean differences were observed between intervention and control for the electroencephalography-based sleep outcomes.

CONCLUSIONS AND RELEVANCE

In this cluster randomized clinical trial, a recreational screen media reduction intervention resulted in a substantial increase in children's engagement in physical activity. The large effect size suggests that the high levels of recreational screen media use seen in many children should be a public health concern.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04098913.

Bright Light During Wakefulness Improves Sleep Quality in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light (III)

Under real-life conditions, increased light exposure during wakefulness seems associated with improved sleep quality, quantified as reduced time awake during bed time, increased time spent in non-rapid eye movement (NREM) sleep, or increased power of the electroencephalogram delta band (0.5-4 Hz). The causality of these important relationships and their dependency on circadian phase and/or time awake has not been studied in depth. To disentangle possible circadian and homeostatic interactions, we employed a forced desynchrony protocol under dim light (6 lux) and under bright light (1300 lux) during wakefulness. Our protocol consisted of a fast cycling sleep-wake schedule (13 h wakefulness—5 h sleep; 4 cycles), followed by 3 h recovery sleep in a within-subject cross-over design. Individuals (8 men) were equipped with 10 polysomnography electrodes. Subjective sleep quality was measured immediately after wakening with a questionnaire. Results indicated that circadian variation in delta power was only detected under dim light. Circadian variation in time in rapid eye movement (REM) sleep and wakefulness were uninfluenced by light. Prior light exposure increased accumulation of delta power and time in NREM sleep, while it decreased wakefulness, especially during the circadian wake phase (biological day). Subjective sleep quality scores showed that participants rated their sleep quality better after bright light exposure while sleeping when the circadian system promoted wakefulness. These results suggest that high environmental light intensity either increases sleep pressure buildup during wakefulness or prevents the occurrence of micro-sleep, leading to improved quality of subsequent sleep.

A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy

OBJECTIVE

In pregnancy melatonin regulates circadian rhythms, induce sleep, and has a neuroprotective positive effect on fetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus, we investigated the effect of blocking blue light on the melatonin profile.

METHODS

A randomized controlled trial (n=30 blue-blocking glasses vs. n=30 control glasses with partial blue-blocking effect) including healthy nulliparous pregnant women in the beginning of the third trimester. Salivary melatonin and subjective sleep were measured before and after two weeks of intervention/control condition. Saliva was sampled at 30-min intervals from 3 h before normal bedtime. Melatonin onset was set at 4.0 pg/ml.

RESULTS

Due to missing data melatonin onset was estimated for 47 participants. At posttreatment, melatonin onset advanced by 28 min in the blue-blocking group compared with the control condition (p=.019). Melatonin levels were significantly higher, favoring the blue-blocking glass condition, at clock time 20:00, 21:00 and 22:00 h, and for sample number 3 and 4. The phase angle (time interval) between melatonin onset and sleep bedtime and sleep onset time increased within the blue blocking group (+45 min and +41 min, respectively), but did not reach statistical significance compared to control condition (+13 min and +26 min, respectively).

CONCLUSION

Blocking blue light in the evening had a positive effect on the circadian system with an earlier onset and rise of melatonin levels in healthy nulliparous pregnant women. This demonstrated the effectiveness and feasibility of a simple non-pharmacological chronobiological intervention during pregnancy.

The Association Between Self-Reported Screen Time, Social Media Addiction, and Sleep Among Norwegian University Students

The aim of this study was to assess the relationship between daily screen time and sleep, evening screen time and sleep, and between social media addiction and sleep in a student population. This cross-sectional study is based on data from a national survey of all college and university students in Norway (the SHoT2018 study; n = 49,051). The sleep outcomes were sleep duration, sleep onset latency, sleep efficiency, and insomnia operationalized according to formal DSM-5 criteria. The results show a strong negative association between time spent on screen-based devices and sleep quality and quantity, and where screen use in bed had more consistent negative associations with sleep. Furthermore, there were higher rates of insomnia among those with higher levels of addiction, and curvilinear relationships with sleep duration, sleep onset latency, and sleep efficiency. Those with higher levels of addiction also had more evening screen time. The findings suggest that screen use plays an important role in students' sleep quantity and quality, where evening screen time has a stronger relationship with sleep compared to total daily screen time. The results also suggest a role of social media addiction, and addictive social media use may be a target for intervention in order to reduce evening screen time.

Mediating Effect of Sleep Quality on the Relationship Between Electronic Screen Media Use and Academic Performance Among College Students

OBJECTIVE

We aimed to examine the effects of sleep quality on the association between pre-bedtime electronic screen media use for entertainment and academic performance among college students. We hypothesized that sleep quality mediates the association between pre-bedtime electronic screen media entertainment use and academic performance among college students.

METHODS

This was a cross-sectional survey with 1385 participants (age 19.99 ± 1.4 years [range, 17-24 years] and 36.82% males) conducted at Shantou University. The levels of academic performance were based on self-reported academic class ranking from average grades of their last final major examinations. Poor sleep quality was defined as a total score of the Pittsburgh Sleep Quality Index >7. The pre-bedtime prolonged electronic screen media use for entertainment (PESM-E) was defined as the use of electronic screen media for entertainment longer than 60 minutes/night after 10:00 p.m. during the past 6 months.

RESULTS

College students with pre-bedtime PESM-E were 1.28-fold more likely to have a poor academic performance than those who used electronic screen media less than 60 minutes (95% confidence interval [CI]: 1.04-1.57, P=0.020). Furthermore, pre-bedtime PESM-E was significantly associated with poor sleep quality (adjusted odds ratio [AOR]=1.87, 95% CI: 1.27-2.74, P=0.001) after controlling for confounders. Mediation model showed that poor sleep quality accounted for 53.08% of the effect of pre-bedtime PESM-E on lower levels of academic performance (Sobel Z=2.04, P=0.041).

CONCLUSION

Pre-bedtime PESM-E is associated with poor academic performance in college students, and this association is mediated by poor sleep quality. Our findings highlight the importance of limiting the use of electronic screen media before bedtime in college students.

The Mediating Role of Emotion Dysregulation and Problematic Internet Use in the Relationship Between Negative Affect and Excessive Daytime Sleepiness: A Structural Equation Model

PURPOSE

The present study aimed to explore the mediating role of emotion dysregulation and problematic Internet use in the relationship between negative affect and excessive daytime sleepiness.

METHODS

This cross-sectional study included 664 Italian adults aged between 18 and 70 years (M = 32.13; SD = 11.71). Participants were asked to complete the Depression Anxiety Stress Scale, the Difficulties in Emotion Regulation Scale, the Compulsive Internet Use Scale-7, and the Epworth Sleepiness Scale to assess negative affect, emotion dysregulation, problematic internet use, and excessive daytime sleepiness, respectively.

RESULTS

According to our results there are significant associations between negative affect, emotion dysregulation, problematic Internet use, and daytime sleepiness. Moreover, the structural equation model showed good fit indices. Emotion dysregulation and problematic Internet use partially mediated the relationship between negative mood and excessive daytime sleepiness.

CONCLUSION

By exploring the role of emotion dysregulation on the association between excessive daytime sleepiness and its possible predictors, our study might represent an important step toward the implementation of psychological intervention for reducing excessive daytime sleepiness. Emotion dysregulation appears to play a significant role in explaining the relationship between negative affect, problematic Internet use, and excessive daytime sleepiness. Thus, it should be considered a treatment target for reducing excessive daytime sleepiness.

A randomized controlled trial on the effects of blue-blocking glasses compared to partial blue-blockers on sleep outcomes in the third trimester of pregnancy

OBJECTIVE

Sleep disturbances are common in pregnancy. Blocking blue light has been shown to improve sleep and may be a suitable intervention for sleep problems during pregnancy. The present study investigated the effects of blue light blocking in the evening and during nocturnal awakenings among pregnant women on primary sleep outcomes in terms of total sleep time, sleep efficiency and mid-point of sleep.

METHODS

In a double-blind randomized controlled trial, 60 healthy nulliparous pregnant women in the beginning of the third trimester were included. They were randomized, using a random number generator, either to a blue-blocking glass intervention (n = 30) or to a control glass condition constituting partial blue-blocking effect (n = 30). Baseline data were recorded for one week and outcomes were recorded in the last of two intervention/control weeks. Sleep was measured by actigraphy, sleep diaries, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale.

RESULTS

The results on the primary outcomes showed no significant mean difference between the groups at posttreatment, neither when assessed with sleep diary; total sleep time (difference = .78[min], 95%CI = -19.7, 21.3), midpoint of sleep (difference = -8.9[min], 95%CI = -23.7, 5.9), sleep efficiency (difference = -.06[%], 95%CI = -1.9, 1.8) and daytime functioning (difference = -.05[score points], 95%CI = -.33, .22), nor by actigraphy; total sleep time (difference = 13.0[min], 95%CI = -9.5, 35.5), midpoint of sleep (difference = 2.1[min], 95%CI = -11.6, 15.8) and sleep efficiency (difference = 1.7[%], 95%CI = -.4, 3.7). On the secondary outcomes, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale the blue-blocking glasses no statistically significant difference between the groups were found. Transient side-effects were reported in both groups (n = 3).

CONCLUSIONS

The use of blue-blocking glasses compared to partially blue-blocking glasses in a group of healthy pregnant participants did not show statistically significant effects on sleep outcomes. Research on the effects of blue-blocking glasses for pregnant women with sleep-problems or circadian disturbances is warranted.

TRIAL REGISTRATION

The trial is registered at ClinicalTrials.gov (NCT03114072).

Sleep and circadian rhythms: pillars of health-a Keystone Symposia report

The human circadian system consists of the master clock in the suprachiasmatic nuclei of the hypothalamus as well as in peripheral molecular clocks located in organs throughout the body. This system plays a major role in the temporal organization of biological and physiological processes, such as body temperature, blood pressure, hormone secretion, gene expression, and immune functions, which all manifest consistent diurnal patterns. Many facets of modern life, such as work schedules, travel, and social activities, can lead to sleep/wake and eating schedules that are misaligned relative to the biological clock. This misalignment can disrupt and impair physiological and psychological parameters that may ultimately put people at higher risk for chronic diseases like cancer, cardiovascular disease, and other metabolic disorders. Understanding the mechanisms that regulate sleep circadian rhythms may ultimately lead to insights on behavioral interventions that can lower the risk of these diseases. On February 25, 2021, experts in sleep, circadian rhythms, and chronobiology met virtually for the Keystone eSymposium "Sleep & Circadian Rhythms: Pillars of Health" to discuss the latest research for understanding the bidirectional relationships between sleep, circadian rhythms, and health and disease.

How Smart Is It to Go to Bed with the Phone? The Impact of Short-Wavelength Light and Affective States on Sleep and Circadian Rhythms

Previously, we presented our preliminary results (N = 14) investigating the effects of short-wavelength light from a smartphone during the evening on sleep and circadian rhythms (Höhn et al., 2021). Here, we now demonstrate our full sample (N = 33 men), where polysomnography and body temperature were recorded during three experimental nights and subjects read for 90 min on a smartphone with or without a filter or from a book. Cortisol, melatonin and affectivity were assessed before and after sleep. These results confirm our earlier findings, indicating reduced slow-wave-sleep and -activity in the first night quarter after reading on the smartphone without a filter. The same was true for the cortisol-awakening-response. Although subjective sleepiness was not affected, the evening melatonin increase was attenuated in both smartphone conditions. Accordingly, the distal-proximal skin temperature gradient increased less after short-wavelength light exposure than after reading a book. Interestingly, we could unravel within this full dataset that higher positive affectivity in the evening predicted better subjective but not objective sleep quality. Our results show disruptive consequences of short-wavelength light for sleep and circadian rhythmicity with a partially attenuating effect of blue-light filters. Furthermore, affective states influence subjective sleep quality and should be considered, whenever investigating sleep and circadian rhythms.

Lifestyle Factors and Sleep Health across the Lifespan

Sleep health, operationalized as a multidimensional construct consisting of sleep regularity, satisfaction, alertness, timing, efficiency, and duration, is an emerging concept in the field of sleep medicine which warrants further investigation. The purpose of the present study was to: (1) compare sleep health across the lifespan, (2) determine lifestyle factors associated with sleep health, and (3) examine whether lifestyle factors associated with sleep health varied between and within age groups. Participants consisted of 3284 individuals (Mean age = 42.70; 45% male) who participated in a cross-sectional online survey of sleep and health. Sleep health was measured using the RU-SATED scale, while demographic and lifestyle factors (e.g., daily social media use, sedentary activity, fast food consumption, etc.) were all self-reported. Sleep health was the highest among older adults (M = 8.09) followed by middle-aged (M = 7.65) and younger adults (M = 7.16). Across age groups, fast-food consumption, daily regularity, and daily TV, social media, or internet use were all negatively correlated with sleep health (ps < 0.05). Few differences in the association between lifestyle factors and sleep health across age groups were found. Overall, these findings may help to inform sleep health promotion efforts by targeting the most pertinent lifestyle factors for promoting sleep health.

Sleep, evening light exposure and perceived stress in healthy nulliparous women in the third trimester of pregnancy

Objective

Sleep disturbances are common in pregnancy, and the prevalence increases during the third trimester. The aim of the present study was to assess sleep patterns, sleep behavior and prevalence of insomnia in pregnant women in the third trimester, by comparing them to a group of non-pregnant women. Further, how perceived stress and evening light exposure were linked to sleep characteristics among the pregnant women were examined.

Methods

A total of 61 healthy nulliparous pregnant women in beginning of the third trimester (recruited from 2017 to 2019), and 69 non-pregnant women (recruited in 2018) were included. Sleep was monitored by actigraphy, sleep diaries and the Bergen Insomnia Scale. The stress scales used were the Relationship Satisfaction Scale, the Perceived Stress Scale and the Pre-Sleep Arousal Scale. Total white light exposure three hours prior to bedtime were also assessed.

Results

The prevalence of insomnia among the pregnant women was 38%, with a mean score on the Bergen Insomnia Scale of 11.2 (SD = 7.5). The corresponding figures in the comparing group was 51% and 12.3 (SD = 7.7). The pregnant women reported lower sleep efficiency (mean difference 3.8; 95% CI = 0.3, 7.3), longer total sleep time derived from actigraphy (mean difference 59.0 minutes; 95% CI = 23.8, 94.2) and higher exposure to evening light (mean difference 0.7; 95% CI = 0.3, 1.2), compared to the non-pregnant group. The evening light exposure was inversely associated with total sleep time derived from actigraphy (B = -8.1; 95% CI = -14.7, -1.5), and an earlier midpoint of sleep (B = -10.3, 95% CI = -14.7, -5.9). Perceived stressors were unrelated to self-reported and actigraphy assessed sleep.

Conclusion

In healthy pregnant participants sleep in the third trimester was preserved quite well. Even so, the data suggest that evening light exposure was related to shorter sleep duration among pregnant women.

Non-pharmacologic treatment of insomnia in primary care settings

INTRODUCTION

Prevalence of insomnia is higher in females and increases with higher age. Besides primary insomnia, comorbid sleep disorders are also common, accompanying different conditions. Considering the possible adverse effects of commonly used drugs to promote sleep, a non-pharmacologic approach should be preferred in most cases. Although generally considered first-line treatment, the non-pharmacologic approach is often underestimated by both patients and physicians.

OBJECTIVE

To provide primary care physicians an up-to-date approach to the non-pharmacologic treatment of insomnia.

METHODS

PubMed, Web of Science, and Scopus databases were searched for relevant articles about the non-pharmacologic treatment of insomnia up to December 2020. We restricted our search only to articles written in English.

MAIN MESSAGE

Most patients presenting with sleep disorder symptoms can be effectively managed in the primary care setting. Primary care physicians may use pharmacologic and non-pharmacologic approaches, while the latter should be generally considered first-line treatment. A primary care physician may opt to refer the patient to a subspecialist for refractory cases.

CONCLUSIONS

This paper provides an overview of current recommendations and up-to-date evidence for the non-pharmacologic treatment of insomnia. This article emphasizes the importance of cognitive-behavioral therapy for insomnia, likewise, exercise and relaxation techniques. Complementary and alternative approaches are also covered, eg, light therapy, aromatherapy, music therapy, and herbal medicine.

Influence of Electronic Devices on Sleep and Cognitive Performance During Athlete Training Camps

Jones, MJ, Dawson, B, Eastwood, PR, Halson, SL, Miller, J, Murray, K, Dunican, IC, Landers, GJ, and Peeling, P. Influence of electronic devices on sleep and cognitive performance during athlete training camps. J Strength Cond Res 35(6): 1620-1627, 2021-This study investigated the effects of removing athletes' electronic devices in the evening on sleep and performance during training camps. Water polo athletes (n = 26) attending a 7-night training camp (study 1) and triathletes (n = 23) attending a 4-night training camp (study 2) were randomly allocated to a no-device group (no electronic devices could be used after dinner or overnight; ND) or control group (unrestricted electronic device use; CON). Sleep was monitored through wrist actigraphy. The ND group completed a questionnaire measuring anxiety related to being unable to use electronic devices ("nomophobia"). Triathletes also completed a psychomotor vigilance test (PVT) at the start and end of camp. Water polo ND athletes went to bed earlier and spent longer time in bed than CON on the first night, but not on other nights. In triathletes, sleep quantity was not different between groups on any night. No statistically significant differences were observed for changes in nomophobia from the first to the last night of camp. No differences in PVT performance were observed between ND and CON triathletes. In conclusion, removal of evening electronic devices does not improve sleep quantity or cognitive performance in athletes during short-duration (4-7 nights) training camps.

Scoping Review of Healthcare Literature on Mobile, Wearable, and Textile Sensing Technology for Continuous Monitoring

Remote monitoring of health can reduce frequent hospitalisations, diminishing the burden on the healthcare system and cost to the community. Patient monitoring helps identify symptoms associated with diseases or disease-driven disorders, which makes it an essential element of medical diagnoses, clinical interventions, and rehabilitation treatments for severe medical conditions. This monitoring can be expensive and time-consuming and provide an incomplete picture of the state of the patient. In the last decade, there has been a significant increase in the adoption of mobile and wearable devices, along with the introduction of smart textile solutions that offer the possibility of continuous monitoring. These alternatives fuel a technology shift in healthcare, one that involves the continuous tracking and monitoring of individuals. This scoping review examines how mobile, wearable, and textile sensing technology have been permeating healthcare by offering alternate solutions to challenging issues, such as personalised prescriptions or home-based secondary prevention. To do so, we have selected 222 healthcare literature articles published from 2007 to 2019 and reviewed them following the PRISMA process under the schema of a scoping review framework. Overall, our findings show a recent increase in research on mobile sensing technology to address patient monitoring, reflected by 128 articles published in journals and 19 articles in conference proceedings between 2014 and 2019, which represents 57.65% and 8.55% respectively of all included articles.

Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness

Smartphone usage strongly increased in the last decade, especially before bedtime. There is growing evidence that short-wavelength light affects hormonal secretion, thermoregulation, sleep and alertness. Whether blue light filters can attenuate these negative effects is still not clear. Therefore, here, we present preliminary data of 14 male participants (21.93 ± 2.17 years), who spent three nights in the sleep laboratory, reading 90 min either on a smartphone (1) with or (2) without a blue light filter, or (3) on printed material before bedtime. Subjective sleepiness was decreased during reading on a smartphone, but no effects were present on evening objective alertness in a GO/NOGO task. Cortisol was elevated in the morning after reading on the smartphone without a filter, which resulted in a reduced cortisol awakening response. Evening melatonin and nightly vasodilation (i.e., distal-proximal skin temperature gradient) were increased after reading on printed material. Early slow wave sleep/activity and objective alertness in the morning were only reduced after reading without a filter. These results indicate that short-wavelength light affects not only circadian rhythm and evening sleepiness but causes further effects on sleep physiology and alertness in the morning. Using a blue light filter in the evening partially reduces these negative effects.

Association Between Reading Habit and Sleep Among Age Over 40 Years Community Residents: A Population-Based Evidence Study

PURPOSE

Sleep disturbance is a paramount public health concern that besets many modern middle-aged and elderly community residents. Reading is important to adults as it facilitates the completion of daily tasks, and might be associated with sleep issues. The present study aimed to analyze the association between reading and sleep using Chinese national survey data.

PATIENTS AND METHODS

The 2018 China Family Panel Studies survey data were used, and the target sample was extracted according to age (>40 years). Reading behavior and reading quantity were chosen as independent variables, and sleep duration, sleep-onset time, and sleep quality were selected as dependent variables. A multilevel mixed linear/ordinal logistic regression model was employed to evaluate the association, and restricted cubic splines with 4 knots were employed to flexibly model the association of reading quantity and sleep duration.

RESULTS

A total of 18,740 adults were selected, and the reading rate was 15.04%. Reading habit was significantly negatively associated with weekday sleep duration, but not with duration at weekends, as determined from the full set of confounders adjusted models. Reading behavior was also associated with delayed sleep-onset time (OR: 0.935, 95% CI: 0.908-0.964), but not with sleep quality. Reading quantity showed a nonlinear relationship with sleep duration, appropriate reading quantity was related with long sleep duration.

CONCLUSION

Reading was associated with short sleep duration on weekdays, but not with sleep quality. Furthermore, reading was related to late sleep-onset time, and for the middle-aged and elderly Chinese populations, appropriate reading quantity was related with long sleep duration.

A Blue-Enriched, Increased Intensity Light Intervention to Improve Alertness and Performance in Rotating Night Shift Workers in an Operational Setting

PURPOSE

This study examined the efficacy of a lighting intervention that increased both light intensity and short-wavelength (blue) light content to improve alertness, performance and mood in night shift workers in a chemical plant.

PATIENTS AND METHODS

During rostered night shifts, 28 workers (46.0±10.8 years; 27 male) were exposed to two light conditions each for two consecutive nights (~19:00-07:00 h) in a counterbalanced repeated measures design: traditional-spectrum lighting set at pre-study levels (43 lux, 4000 K) versus higher intensity, blue-enriched lighting (106 lux, 17,000 K), equating to a 4.5-fold increase in melanopic illuminance (24 to 108 melanopic illuminance). Participants completed the Karolinska Sleepiness Scale, subjective mood ratings, and the Psychomotor Vigilance Task (PVT) every 2-4 hours during the night shift.

RESULTS

A significant main effect of time indicated KSS, PVT mean reaction time, number of PVT lapses (reaction times > 500 ms) and subjective tension, misery and depression worsened over the course of the night shift (p<0.05). Percentage changes in KSS (p<0.05, partial η²=0.14) and PVT mean reaction time (p<0.05, partial η²=0.19) and lapses (p<0.05, partial η²=0.17) in the middle and end of night shift, expressed relative to start of shift, were significantly improved during the lighting intervention compared to the traditional lighting condition. Self-reported mood did not significantly differ between conditions (p>0.05).

CONCLUSION

Our findings, showing improvements in alertness and performance with exposure to blue-enriched, increased intensity light, provide support for light to be used as a countermeasure for impaired alertness in night shift work settings.

Melatonin treatment of repetitive behavioral deficits in the Cntnap2 mouse model of autism spectrum disorder

Nighttime light pollution is linked to metabolic and cognitive dysfunction. Many patients with autism spectrum disorders (ASD) show disturbances in their sleep/wake cycle, and may be particularly vulnerable to the impact of circadian disruptors. In this study, we examined the impact of exposure to dim light at night (DLaN, 5 lx) in a model of ASD: the contactin associated protein-like 2 knock out (Cntnap2 KO) mice. DLaN was sufficient to disrupt locomotor activity rhythms, exacerbate the excessive grooming and diminish the social preference in Cntnap2 mutant mice. On a molecular level, DLaN altered the phase and amplitude of PER2:LUC rhythms in a tissue-specific manner in vitro. Daily treatment with melatonin reduced the excessive grooming of the mutant mice to wild-type levels and improved activity rhythms. Our findings suggest that common circadian disruptors such as light at night should be considered in the management of ASD.

Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep: A systematic review and meta-analysis

The sleep-wake and circadian cycles are influenced by light, particularly in the short-wavelength portion of the visible spectrum. Most personal light-emitting electronic devices are enriched in this so-called "blue" light. Exposure to these devices in the evening can disturb sleep. Interventions to reduce short-wavelength light exposure before bedtime may reduce adverse effects on sleep. We conducted a systematic review and meta-analysis to examine the effect of wearing color-tinted lenses (e.g. orange or amber) in frames to filter short-wavelength light exposure to the eye before nocturnal sleep. Outcomes were self-reported or objective measures of nocturnal sleep. Relatively few (k = 12) studies have been done. Study findings were inconsistent, with some showing benefit and others showing no effect of intervention. Meta-analyses yielded a small-to-medium magnitude combined effect size for sleep efficiency (Hedge's g = 0.31; 95% CI: -0.05, 0.66; I2 = 38.16%; k = 7), and a small-to-medium combined effect size for total sleep time (Hedge's g = 0.32; 95% CI: 0.01, 0.63; I2 = 12.07%; k = 6). For self-report measures, meta-analysis yielded a large magnitude combined effects size for Pittsburgh Sleep Quality Index ratings (Hedge's g = -1.25; 95% CI: -2.39, -0.11; I2 = 36.35%; k = 3) and a medium combined effect size for total sleep time (Hedge's g = 0.51; 95% CI: 0.18, 0.84; I2 = 0%; k = 3), Overall, there is some, albeit mixed, evidence that this approach can improve sleep, particularly in individuals with insomnia, bipolar disorder, delayed sleep phase syndrome, or attention-deficit hyperactive disorder. Considering the ubiquitousness of short-wavelength-enriched light sources, future controlled studies to examine the efficacy of this approach to improve sleep are warranted. Systematic review registration: PROSPERO 2018 CRD42018105854.

Objective and Subjective Characteristics of Vigilance under Different Narrow-Bandwidth Light Conditions: Do Shorter Wavelengths Have an Alertness-Enhancing Effect?

The aim of this study was to explore the effects of 20 min of narrow-bandwidth light exposure of different wavelengths (455, 508, and 629 nm, with irradiance of 14 µW/cm2) on various neuropsychological and neurophysiological parameters of vigilance in healthy volunteers and to provide further evidence of the behavioral (subjective sleepiness, reaction time) and electrophysiological (P300 and spectral characteristics) responses to light. The results show that the short-wavelength light condition (455 nm) was found to be most effective in terms of its alerting effect for the following variables: subjective sleepiness, latency of P300 response, and absolute EEG power in higher beta (24-34 Hz) and gamma (35-50 Hz) range at each of the 19 recording electrodes. However, no differences in current power density were observed at the level of cortical EEG sources estimated by exact low-resolution electromagnetic tomography. Our results are in line with other research that shows significant alerting effects of blue (short-wavelength) light in comparison to lights of longer wavelengths. Our results confirm earlier findings that exposure to short-wavelength light during the day may enhance cognitive performance in task-specific scenarios.

Short-term efficacy of reducing screen media use on physical activity, sleep, and physiological stress in families with children aged 4-14: study protocol for the SCREENS randomized controlled trial

BACKGROUND

During the recent decade presence of digital media, especially handheld devices, in everyday life, has been increasing. Survey data suggests that children and adults spend much of their leisure on screen media, including use of social media and video services. Despite much public debate on possible harmful effects of such behavioral shifts, evidence from rigorously conducted randomized controlled trials in free-living settings, investigating the efficacy of reducing screen media use on physical activity, sleep, and physiological stress, is still lacking. Therefore, a family and home-based randomized controlled trial - the SCREENS trial - is being conducted. Here we describe in detail the rationale and protocol of this study.

METHODS

The SCREENS pilot trial was conducted during the fall of 2018 and spring of 2019. Based on experiences from the pilot study, we developed a protocol for a parallel group randomized controlled trial. The trial is being conducted from May 2019 to ultimo 2020 in 95 families with children 4-14 years recruited from a population-based survey. As part of the intervention family members must handover most portable devices for a 2-week time frame, in exchange for classic mobile phones (not smartphones). Also, entertainment-based screen media use during leisure must be limited to no more than 3 hours/week/person. At baseline and follow-up, 7-day 24-h physical activity will be assessed using two triaxial accelerometers; one at the right hip and one the middle of the right thigh. Sleep duration will be assessed using a single channel EEG-based sleep monitor system. Also, to assess physiological stress (only assessed in adults), parameters of 24-h heart rate variability, the cortisol awakening response and diurnal cortisol slope will be quantified using data sampled over three consecutive days. During the study we will objectively monitor the families' screen media use via different software and hardware monitoring systems.

DISCUSSION

Using a rigorous study design with state-of-the-art methodology to assess outcomes and intervention compliance, analyses of data from the SCREENS trial will help answer important causal questions of leisure screen media habits and its short-term influence on physical activity, sleep, and other health related outcomes among children and adults.

TRIAL REGISTRATION

NCT04098913 at https://clinicaltrials.gov [20-09-2019, retrospectively registered].

Demographics and Health Behavior of Video Game and eSports Players in Germany: The eSports Study 2019

The number of video game and eSports players is steadily rising. Since little is known about their health behavior to date, the present study examines the demographics and health behavior of video game and eSports players. In this cross-sectional study, data on demographics, health status, physical activity, nutrition, sleep, and video game usage were assessed via a web-based survey of n = 1066 players (91.9% male; 22.9 ± 5.9 years; body mass index (BMI): 24.6 ± 4.8 kg/m²) in Germany in 2018. The majority of respondents (95%) reported a good to excellent health status. Two thirds (66.9%) engaged in moderate to vigorous physical activity for more than 2.5 h/week. The average duration of sitting and sleep time was 7.7 ± 3.6 h/day and 7.1 ± 1.3 h/day, respectively. Mean fruit and vegetable consumption was 2.7 ± 1.8 portions/day. Video games were played for 24.4 ± 15.9 h/week on average. Partial Spearman correlations revealed poor positive associations of video game play time to sedentary behavior (rho = 0.15; p < 0.01) and BMI (rho = 0.11; p < 0.01), as well as a poor negative association to self-reported health status (rho = -0.14; p < 0.01). These results indicate the good subjective health of this target group. Nevertheless, the high amount of video game play time and its poor negative association to health status indicate a need for specific health promotion strategies for this target group.

Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures

The last several decades have been characterized by the widespread usage of digital devices, especially smartphones. At the same time, there have been reports of both decline in sleep duration and quality and male fertility decline. The aim of this study was to assess the relationship between evening exposure to the light-emitting screens of digital media devices and measures of both sleep and sperm quality. Semen samples were obtained from 116 men undergoing fertility evaluation for the following sperm variables: volume (mL), pH, sperm concentration (million/mL), motility percentage (progressive% + non-progressive motility%), and total sperm count. Exposure to the screens of electronic devices and sleep habits was obtained by means of a questionnaire. Smartphone and tablet usage in the evening and after bedtime was negatively correlated with sperm motility (-0.392; -0.369; p < .05), sperm progressive motility (-0.322; -0.299; p < .05), and sperm concentration (-0.169; p < .05), and positively correlated with the percentage of immotile sperm (0.382; 0.344; p < .05). In addition, sleep duration was positively correlated with sperm total and progressive motility (0.249; 0.233; p < .05) and negatively correlated with semen pH (-0.349; p < .05). A significant negative correlation was observed between subjective sleepiness and total and progressive motility (-0.264; p < .05) as well as total motile sperm number (-0.173; p < .05). The results of this study support a link between evening and post-bedtime exposure to light-emitting digital media screens and sperm quality. Further research is required to establish the proposed causative link and may lead to the future development of relevant therapeutic and lifestyle interventions.

Burnout, Perceived Stress, Sleep Quality, and Smartphone Use: A Survey of Osteopathic Medical Students

Context

Burnout is a psychological syndrome that results from prolonged exposure to stressful work activities and includes 3 dimensions: emotional exhaustion (EE), depersonalization (DP), and low sense of personal accomplishment (PA). Burnout is a widespread problem in numerous professions but is particularly high among medical students, residents, and early-career physicians compared with college graduates of similar age. However, minimal research has addressed burnout in osteopathic medical students.

Objective

To assess levels of burnout in osteopathic medical students and to examine the relationship among burnout, perceived stress, sleep quality, and smartphone use.

Methods

This study used a cross-sectional study design and an anonymous, electronic questionnaire service to administer the Maslach Burnout Inventory, the Perceived Stress Scale-4, the Pittsburgh Sleep Quality index, and the Smartphone Addiction Scale Short Version.

Results

A total of 385 participants (mean [SD] age, 25 [2.4] years; 208 [54.0%] women; 286 [74.3%] white; 138 [35.8%] second-year osteopathic medical students [OMSs]) completed the survey. Of the 385 participants, 9 (2.3%) reported high EE, 67 (17.4) reported high DP, and 310 (80.5) reported a high level of low PA. When comparing dimensions of burnout by gender, only levels of PA differed by gender, with men reporting higher levels of burnout compared with women (χ1 2=5.2, P=.022). Further, levels of DP differed by year in medical school (χ2=17.3, P=.008), with post-hoc comparisons showing differences between OMS I and OMS III (F=4.530, df=3, P=.004). Linear regression models showed that higher perceived stress (standardized β=0.5, P<.001), poorer sleep quality (standardized β=0.2, P=.001), and higher smartphone addiction scores (standardized β=0.1, P<.001) were associated with higher EE. Similarly, higher perceived stress (standardized β=0.2, P<.001), poorer sleep quality (standardized β=0.2, P=.001), and higher smartphone addiction scores (standardized β=0.2, P=.001) were associated with higher DP. Only higher perceived stress was associated with higher levels of low PA (standardized β=−0.4, P<.001).

Conclusions

These findings suggest independent associations with EE, DP, perceived stress, sleep quality, and smartphone use. Additional research with a larger, more diverse sample is needed to confirm these findings. If confirmed, wellness interventions can be designed to target 2 modifiable factors: sleep quality and smartphone use.

Perception of Sleep Disturbances due to Bedtime Use of Blue Light-Emitting Devices and Its Impact on Habits and Sleep Quality among Young Medical Students

Introduction

The use of blue light-emitting devices (smartphones, tablets, and laptops) at bedtime has negative effects on sleep due to light stimulation and/or problematic excessive use. We aimed to evaluate, among young medical students, if the perception of sleep disturbances due to bedtime use of these devices is consistent with healthier habits and a better sleep quality.

Materials and methods

294 medical students in medicine and pharmacy from the Faculty of Medicine and Pharmacy of Rabat, Morocco, took part in this anonymous and voluntary cross-sectional study and answered an electronic questionnaire. Student and Mann–Whitney U tests were used to compare variables between 2 groups based on their perception of sleep disturbances. The level of significance was p ≤ 0.05.

Results

286 students (97.3%) used a blue light-emitting smart device at bedtime before sleep, and sleep quality was poor (Pittsburgh Sleep Quality Index, PSQI > 5) in 101 students (35.3%). The perception of sleep disturbances due to this night usage was reported by 188 of them (65.7%). In this group, 154 (81.9%) used their device with all the lights turned off in the room (p=0.02), 34 (18.1%) put devices under pillows (p=0.04), 114 (60.6%) interrupted sleep to check messages (p < 0.001), and the mean duration use of these technologies at bedtime was 2 h ± 23 min per night (p=0.02). Also, the mean sleep duration was 6.3 hours ± 1.25 (p=0.04), 119 (63.3%) presented fatigue on waking more than one time per week (p=0.04), and 76 (40.4%) presented poor sleep quality (75.2% of the students with PSQI > 5) (p=0.005).

Conclusions

Despite the perception of sleep disturbances due to bedtime use of blue light-emitting devices, unhealthy sleep habits tend to be frequent in young medical students and worrying because it is associated to significant poor sleep quality.

Bed and rise times during the Age of Enlightenment: A case report

Studies have shown that our modern electrical lighting environment reduces naturally occurring seasonal variations in sleep-wake rhythms, such as longer sleep during the winter versus summer. However, less is known about how timing and duration of sleep were affected by the seasons in the premodern era, before the invention of electrical lighting. The Swedish researcher Olof Hiorter collected and documented geophysical data every hour during wakefulness in Uppsala, Sweden, between December 1746 and November 1747. In this way, his bed and rise times could be approximated. The data revealed that Hiorter's rise times occurred around 1 hr before sunrise in winter versus 1 hr after sunrise in summer. No such association was observed between the time of sunset and Hiorter's bedtimes. Finally, the time in bed was about 3.5-4 hr shorter in summer compared to winter. This 273-year-old case report suggests that time in bed and rise times of people from the premodern era exhibited seasonal variations.

Parents still matter: the influence of parental enforcement of bedtime on adolescents’ depressive symptoms

Study Objectives

The aim of the current study was to test a multilevel mediation model that examined how adolescent sleep duration might be linked to depressive symptoms via their daytime energy levels. Furthermore, the study examined how parents’ enforcement of various types of bedtime rules predicted the duration of adolescent sleep.

Methods

A total of 193 adolescent (ages 14–17; Mage = 15.7 years old, SD = .94; 54.4% female; 71% Caucasian) and parent dyads completed baseline, online surveys, and adolescents also completed online 7-day, twice-daily (i.e. morning and evening) reports of their sleep duration (morning diary) and their energy levels and depressive symptoms throughout the day (evening diary). Parents (Mage = 47.6 years old, SD = 5.4; 80% female) completed assessments of enforcement of bedtime-related rules (i.e. bedtime, cessation of electronic media usage, prohibiting afternoon/evening caffeine consumption). Multilevel modeling enabled the testing of the mediation model both at the between-person level and within individuals.

Results

Results suggested that adolescents’ energy levels mediated the association between adolescents’ sleep duration and depressive symptoms. Furthermore, both greater enforcement of bedtimes and later school start times predicted longer sleep durations for adolescents, and were indirectly associated with adolescents’ depressive symptoms.

Conclusions

These findings underscore the importance of adolescents obtaining sufficient sleep to support their mental health and suggest a critical point of intervention for preventing or decreasing insufficient sleep. Given the diverse threats to adolescents’ sleep as well as adolescents’ desire for greater independence, collaborative, autonomy-promoting bedtime limit-setting is recommended to support adolescents’ well-being.

Removing Short Wavelengths From Polychromatic White Light Attenuates Circadian Phase Resetting in Rats

Visible light is the principal stimulus for resetting the mammalian central circadian pacemaker. Circadian phase resetting is most sensitive to short-wavelength (blue) visible light. We examined the effects of removing short-wavelengths < 500 nm from polychromatic white light using optical filters on circadian phase resetting in rats. Under high irradiance conditions, both long- (7 h) and short- (1 h) duration short-wavelength filtered (< 500 nm) light exposure attenuated phase-delay shifts in locomotor activity rhythms by (∼40-50%) as compared to unfiltered light exposure. However, there was no attenuation in phase resetting under low irradiance conditions. Additionally, the reduction in phase-delay shifts corresponded to regionally specific attenuation in molecular markers of pacemaker activation in response to light exposure, including c-FOS, Per1 and Per2. These results demonstrate that removing short-wavelengths from polychromatic white light can attenuate circadian phase resetting in an irradiance dependent manner. These results have important implications for designing and optimizing lighting interventions to enhance circadian adaptation.