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Clocks & Sleep
Number of Followers: 1  Open Access journalISSN (Online) 2624-5175 Published by MDPI  [249 journals]
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- Clocks & Sleep, Vol. 5, Pages 21-33: Habitual Sleep Patterns and Chronic
Sleep Problems in Relation to Sex, Age, and Circadian Preference in a
Population-Based Sample of Norwegian Adults
Authors: Ingvild West Saxvig, Bjørn Bjorvatn, Siri Waage
First page: 21
Abstract: Sleep patterns and problems vary in relation to internal (e.g., sex, age, circadian preference) and external (e.g., social structures) factors. The main aim of the present study was to describe habitual sleep patterns and chronic sleep problems in a population-based sample of Norwegian adults. During spring 2022, a sample of 1028 adults completed an online survey on sleep habits and problems. Response rate was 33.5%. The survey included the Munich ChronoType Questionnaire and items on circadian preference and chronic sleep problems. Mean workday sleep duration was 7:19 h (±199 min), and shorter in males (p = 0.035) and evening persons (p = 0.003). Short workday sleep duration (<6 h) was reported by 3.1% and was associated with evening preference (p = 0.001). Mean social jetlag was 0:51 h (±75 min), and longer in males (p = 0.036), younger adults (p < 0.001) and evening persons (p < 0.001). Long social jetlag (≥2 h) was reported by 11.2% and associated with younger age (p < 0.001) and evening preference (p < 0.001). Chronic sleep problems (≥3 months) were reported by 44.1%, and associated with female sex (p < 0.001) and evening preference (p = 0.002). Results underscore the importance of considering evening circadian preference as a risk factor for short workday sleep duration, long social jetlag and self-reported chronic sleep problems.
Citation: Clocks & Sleep
PubDate: 2023-01-06
DOI: 10.3390/clockssleep5010003
Issue No: Vol. 5, No. 1 (2023)
- Clocks & Sleep, Vol. 5, Pages 34-44: Pregnant Women’s Attitudes and
Beliefs towards Sleep and Exercise: A Cross-Sectional Survey
Authors: Summer Cannon, Melanie Hayman, Michele Lastella
First page: 34
Abstract: As many as 80% of women report experiencing poor sleep throughout pregnancy. Exercise is associated with many health benefits during pregnancy and is established as a non-pharmacological method to improve sleep in both pregnant and non-pregnant populations. Given the importance of sleep and exercise during pregnancy, the aim of this cross-sectional study was to (1) examine pregnant women’s attitudes and beliefs towards sleep and exercise during pregnancy, and (2) investigate the barriers women face to achieving good sleep and engaging in healthy levels of exercise. Participants were comprised of 258 pregnant Australian women (31.3 ± 5.1 years) who completed a 51-question online survey. Almost all (98%) participants believed exercise during pregnancy to be safe, whilst over half (67%) believed participating in more exercise will improve their sleep. Over 70% of participants reported experiencing barriers such as physical symptoms related to pregnancy that negatively impacted their ability to exercise. Almost all (95%) participants reported experiencing barriers to sleep in their current pregnancy. Present findings suggest that overcoming intrapersonal barriers should be a priority for any intervention aiming to improve sleep or increase exercise levels in pregnant populations. Findings from the present study highlight the need for a better understanding of women’s sleep experiences during pregnancy, and demonstrate how exercise may improve sleep and health outcomes.
Citation: Clocks & Sleep
PubDate: 2023-01-17
DOI: 10.3390/clockssleep5010004
Issue No: Vol. 5, No. 1 (2023)
- Clocks & Sleep, Vol. 5, Pages 45-46: Acknowledgment to the Reviewers of
Clocks & Sleep in 2022
Authors: Clocks & Sleep Editorial Office
First page: 45
Abstract: High-quality academic publishing is built on rigorous peer review [...]
Citation: Clocks & Sleep
PubDate: 2023-01-28
DOI: 10.3390/clockssleep5010005
Issue No: Vol. 5, No. 1 (2023)
- Clocks & Sleep, Vol. 5, Pages 1-9: Changes in Sleep Regularity and
Perceived Life Stress across the COVID-19 Pandemic: A Longitudinal
Analysis of a Predominately Female United States Convenience Sample
Authors: Ryan Bottary, Eric C. Fields, Loren Ugheoke, Dan Denis, Janet M. Mullington, Tony J. Cunningham
First page: 1
Abstract: The Coronavirus Disease 2019 (COVID-19) pandemic had a profound impact on sleep and psychological well-being for individuals worldwide. This pre-registered investigation extends our prior study by tracking self-reported social jetlag (SJL), social sleep restriction (SSR), and perceived life stress from May 2020 through October 2021. Using web-based surveys, we collected self-reported sleep information with the Ultrashort Munich Chronotype Questionnaire at three additional timepoints (September 2020, February 2021 and October 2021). Further, we measured perceived life stress with the Perceived Stress Scale at two additional timepoints (February 2021 and October 2021). In a subsample of 181, predominantly female (87%), United States adults aged 19–89 years, we expanded our prior findings by showing that the precipitous drop in SJL during the pandemic first wave (May 2020), compared to pre-pandemic (February, 2020), rapidly rose with loosening social restrictions (September 2020), though never returned to pre-pandemic levels. This effect was greatest in young adults, but not associated with self-reported chronotype. Further, perceived life stress decreased across the pandemic, but was unrelated to SJL or SSR. These findings suggest that sleep schedules were sensitive to pandemic-related changes in social restrictions, especially in younger participants. We posit several possible mechanisms supporting these findings.
Citation: Clocks & Sleep
PubDate: 2022-12-26
DOI: 10.3390/clockssleep5010001
Issue No: Vol. 5, No. 1 (2022)
- Clocks & Sleep, Vol. 5, Pages 10-20: Portability of Polygenic Risk Scores
for Sleep Duration, Insomnia and Chronotype in 33,493 Individuals
Authors: Anna Perkiö, Ilona Merikanto, Katri Kantojärvi, Tiina Paunio, Nasa Sinnott-Armstrong, Samuel E. Jones, Hanna M. Ollila
First page: 10
Abstract: Polygenic risk scores (PRSs) estimate genetic liability for diseases and traits. However, the portability of PRSs in sleep traits has remained elusive. We generated PRSs for self-reported insomnia, chronotype and sleep duration using summary data from genome-wide association studies (GWASs) performed in 350,000 to 697,000 European-ancestry individuals. We then projected the scores in two independent Finnish population cohorts (N = 33,493) and tested whether the PRSs were associated with their respective sleep traits. We observed that all the generated PRSs were associated with their corresponding traits (p < 0.05 in all cases). Furthermore, we found that there was a 22.2 min difference in reported sleep between the 5% tails of the PRS for sleep duration (p < 0.001). Our findings indicate that sleep-related PRSs show portability across cohorts. The findings also demonstrate that sleep measures using PRSs for sleep behaviors may provide useful instruments for testing disease and trait associations in cohorts where direct sleep parameters have not yet been measured.
Citation: Clocks & Sleep
PubDate: 2022-12-30
DOI: 10.3390/clockssleep5010002
Issue No: Vol. 5, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 475-496: Objective Measures of Immediate
“Energizing” Effect of Light: Studies Review and Data Analysis
Authors: Konstantin V. Danilenko
First page: 475
Abstract: While the energizing effect of light has been known since the early years of light therapy, its reliable detection using objective measures is still not well-established. This review aims to ascertain the immediate energizing effect of light and determine its best indicators. Sixty-four articles published before July 2022 were included in the review. The articles described 72 (sub-)studies performed in healthy individuals. Fourteen measures were analyzed. The analysis showed that light causes an energizing effect that can be best documented by measuring core (rectal) body temperature: the proportion of the studies revealing increasing, unchanging, and decreasing rectal temperature was 13/6/1. The second most suitable indicator was heart rate (10/22/1), which showed concordant changes with rectal temperature (a trend, seven mutual studies). There is no evidence from the reviewed articles that oxygen consumption, skin conductance, blood pressure, heart rate variability, non-rectal inner temperature (combined digestive, tympanic, and oral), skin temperature, or cortisol levels can provide light effect detection. Four other measures were found to be unsuitable as well but with less certainty due to the low number of studies (≤3): skin blood flow, noradrenaline, salivary alpha-amylase, and thyroid-stimulating hormone levels. On the other hand, light exposure had a noticeable effect on sympathetic nerve activity measured using microneurography; however, this measure can be accepted as a marker only tentatively as it was employed in a single study. The analysis took into account three factors—study limitation in design/analysis, use of light in day- or nighttime, and relative brightness of the light stimulus—that were found to significantly influence some of the analyzed variables. The review indicates that the energizing effect of light in humans can be reliably detected using rectal temperature and heart rate.
Citation: Clocks & Sleep
PubDate: 2022-09-26
DOI: 10.3390/clockssleep4040038
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 497-507: The Impact of Missing Data and
Imputation Methods on the Analysis of 24-Hour Activity Patterns
Authors: Lara Weed, Renske Lok, Dwijen Chawra, Jamie Zeitzer
First page: 497
Abstract: The purpose of this study is to characterize the impact of the timing and duration of missing actigraphy data on interdaily stability (IS) and intradaily variability (IV) calculation. The performance of three missing data imputation methods (linear interpolation, mean time of day (ToD), and median ToD imputation) for estimating IV and IS was also tested. Week-long actigraphy records with no non-wear or missing timeseries data were masked with zeros or ‘Not a Number’ (NaN) across a range of timings and durations for single and multiple missing data bouts. IV and IS were calculated for true, masked, and imputed (i.e., linear interpolation, mean ToD and, median ToD imputation) timeseries data and used to generate Bland–Alman plots for each condition. Heatmaps were used to analyze the impact of timings and durations of and between bouts. Simulated missing data produced deviations in IV and IS for longer durations, midday crossings, and during similar timing on consecutive days. Median ToD imputation produced the least deviation among the imputation methods. Median ToD imputation is recommended to recapitulate IV and IS under missing data conditions for less than 24 h.
Citation: Clocks & Sleep
PubDate: 2022-09-27
DOI: 10.3390/clockssleep4040039
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 508-519: A Social Media Outage Was
Associated with a Surge in Nomophobia, and the Magnitude of Change in
Nomophobia during the Outage Was Associated with Baseline Insomnia
Authors: Haitham Jahrami, Feten Fekih-Romdhane, Zahra Saif, Nicola Luigi Bragazzi, Seithikurippu R. Pandi-Perumal, Ahmed S. BaHammam, Michael V. Vitiello
First page: 508
Abstract: We examined the immediate impact of a social media outage on nomophobia and associated symptoms using a longitudinal cohort design. Data were collected at two timepoints, baseline (T1) and during the social media outage of 4 October 2021 (T2). T1 was collected in August–September 2021 as part of the baseline of an ongoing study. The nomophobia questionnaire (NMP-Q), Generalized Anxiety Disorder-7 scale (GAD-7), and Athens insomnia scale (AIS) were administered to 2706 healthy participants from the general Bahraini population (56% females, mean age 33.57 ± 11.65 years). Approximately one month later, during the social media outage, 306 of the study participants were opportunistically assessed using the NMP-Q. At baseline, we found that nomophobia levels strongly correlated positively with both insomnia (p = 0.001) and anxiety symptoms (p = 0.001). This is the first report to examine the impact of a social media outage on nomophobia. Our findings indicate that symptoms of nomophobia increased significantly during a social media outage. Baseline insomnia scores predicted a surge in the global scores of nomophobia symptoms during a social media outage.
Citation: Clocks & Sleep
PubDate: 2022-09-27
DOI: 10.3390/clockssleep4040040
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 520-534: Sleep Habits in Pairs of Japanese
High School Students and Their Mothers in Summer and Autumn
Authors: Koh Mizuno, Kazue Okamoto-Mizuno, Akiko Maeda
First page: 520
Abstract: This study aimed to examine the sleep habits in pairs of Japanese high school students and their mothers in the summer and autumn. Nineteen pairs of high school students and their mothers participated in this study. Wrist actigraphy, subjective sleep evaluations, and bedroom environmental measurements (temperature, humidity, and light) were performed for a duration of one week. The results of a split-plot analysis of variance revealed no significant difference in the actigraphically evaluated time spent in bed (TIB) between the seasons and between the mothers and students. The TIB was approximately 6 h on weekdays, and significantly lengthened to approximately 7 h on weekends (p < 0.05). The average sleep efficiency values recorded were higher than 90%. The mothers showed significantly advanced sleep phases compared to those of the students (p < 0.05). In addition, the waking time on Monday morning was significantly correlated between the mothers and students in the summer and autumn (p < 0.05). A perceived sleep loss “almost every day” or “several times per week” was reported by approximately half of the mothers and students in each season. The students occasionally fell into nocturnal sleep with the room light turned on. These results suggest that sleep hygiene education considering life habit characteristics is required to ensure sufficient sleep time.
Citation: Clocks & Sleep
PubDate: 2022-09-28
DOI: 10.3390/clockssleep4040041
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 535-548: STOP-Bang Score and Prediction of
Severity of Obstructive Sleep Apnea in a First Nation Community in
Saskatchewan, Canada
Authors: James A. Dosman, Chandima P. Karunanayake, Mark Fenton, Vivian R. Ramsden, Jeremy Seeseequasis, Delano Mike, Warren Seesequasis, Marie Neubuhr, Robert Skomro, Shelley Kirychuk, Donna C. Rennie, Kathleen McMullin, Brooke P. Russell, Niels Koehncke, Sylvia Abonyi, Malcolm King, Punam Pahwa
First page: 535
Abstract: The STOP-Bang questionnaire is an easy-to-administer scoring model to screen and identify patients at high risk of obstructive sleep apnea (OSA). However, its diagnostic utility has never been tested with First Nation peoples. The objective was to determine the predictive parameters and the utility of the STOP-Bang questionnaire as an OSA screening tool in a First Nation community in Saskatchewan. The baseline survey of the First Nations Sleep Health Project (FNSHP) was completed between 2018 and 2019. Of the available 233 sleep apnea tests, 215 participants completed the STOP-Bang score questionnaire. A proportional odds ordinal logistic regression analysis was conducted using the total score of the STOP-Bang as the independent variable with equal weight given to each response. Predicted probabilities for each score at cut-off points of the Apnea Hypopnea Index (AHI) were calculated and plotted. To assess the performance of the STOP-Bang questionnaire, sensitivity, specificity, positive predictive values (PPVs), negative predictive values (NPVs), and area under the curve (AUC) were calculated. These data suggest that a STOP-Bang score ≥ 5 will allow healthcare professionals to identify individuals with an increased probability of moderate-to-severe OSA, with high specificity (93.7%) and NPV (91.8%). For the STOP-Bang score cut-off ≥ 3, the sensitivity was 53.1% for all OSA and 72.0% for moderate-to-severe OSA. For the STOP-Bang score cut-off ≥ 3, the specificity was 68.4% for all OSA and 62.6% for moderate-to-severe OSA. The STOP-Bang score was modestly superior to the symptom of loud snoring, or loud snoring plus obesity in this population. Analysis by sex suggested that a STOP-Bang score ≥ 5 was able to identify individuals with increased probability of moderate-to-severe OSA, for males with acceptable diagnostic test accuracy for detecting participants with OSA, but there was no diagnostic test accuracy for females.
Citation: Clocks & Sleep
PubDate: 2022-10-12
DOI: 10.3390/clockssleep4040042
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 549-560: NREM Sleep Parasomnias Commencing
in Childhood: Trauma and Atopy as Perpetuating Factors
Authors: Cara Walsh, Lee Mitchell, Maria Hrozanova, Serafeim-Chrysovalantis Kotoulas, Christopher Derry, Ian Morrison, Renata L. Riha
First page: 549
Abstract: Objective/Background: Phenotyping of non-rapid-eye-movement (NREM) parasomnias is currently poorly undertaken. This study aimed to determine whether there are differences phenotypically among childhood-, adolescent-, and adult-onset NREM parasomnias continuing into and presenting in adulthood. Patients/Methods: A retrospective, cohort study of patients presenting with NREM parasomnia between 2008 and 2019 (n = 307) was conducted. Disorders included sleepwalking (n = 231), night terrors (n = 150), sexualised behaviour in sleep (n = 50), and sleep-related eating disorder (n = 28). Results: Compared to the adult-onset NREM behaviours group, the childhood- and adolescent-onset groups were more likely to have a family history of NREM behaviours (p < 0.001), experience a greater spectrum of NREM disorders (p = 0.001), and report a history of sleep-talking significantly more frequently (p = 0.014). Atopy was most prevalent in the childhood-onset group (p = 0.001). Those with childhood-onset NREM parasomnias were significantly more likely to arouse from N3 sleep on video polysomnography (p = 0.0003). Psychiatric disorders were more likely to be comorbid in the adult-onset group (p = 0.012). A history of trauma coinciding with onset of NREM behaviours was significantly more common in the childhood- and adolescent-onset groups (p < 0.001). Conclusions: Significant differences exist across childhood-, adolescent-, and adult-onset NREM parasomnia presenting in adulthood. This study suggests that adult-onset slow-wave sleep disorders may be confounded by psychiatric disorders resulting in nocturnal sleep disruption and that unresolved traumatic life experiences perpetuate NREM disorders arising in childhood and comprise one of the strongest external risk factors for triggering and perpetuating these disorders in adolescence.
Citation: Clocks & Sleep
PubDate: 2022-10-17
DOI: 10.3390/clockssleep4040043
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 561-576: The Intention to React to Sounds
Induces Sleep Disturbances and Alters Brain Responses to Sounds during
Sleep: A Pilot Study
Authors: Selina Ladina Combertaldi, Anna Zoé Wick, Björn Rasch
First page: 561
Abstract: Background: Pre-sleep intentions to react to stimuli during sleep affect sleep processes in spite of reductions in conscious awareness. Here, we compare influences of sounds presented during sleep (with and without intentions to react) with the effect of pre-sleep intentions on sleep (with and without sounds being present during sleep). Methods: Twenty-six young, healthy participants spent two experimental nights in the sleep laboratory. On one night, they were instructed to react to sounds during sleep (“on call”); on the other night, not (“neutral”). Unknown to the subjects, sounds were presented at a low volume in both nights in one group. No sound was presented in any of the two nights in the other group. Results: The instruction of being “on call” decreased objective sleep efficiency independently of sounds being present or not. In addition, event-related responses to sounds as well as slow-wave activity were reduced when being “on call”. Conclusions: Pre-sleep intentions to react impair sleep independently of sounds actually being present and influence brain responses to sounds during sleep. Our results highlight the importance of subjective relevance for reducing negative impact of external noise sources such as traffic or church bells.
Citation: Clocks & Sleep
PubDate: 2022-10-19
DOI: 10.3390/clockssleep4040044
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 577-594: Brighter Time: A Smartphone App
Recording Cognitive Task Performance and Illuminance in Everyday Life
Authors: Marina Gardesevic, Altug Didikoglu, Samuel J. D. Lawrence, Céline Vetter, Timothy M. Brown, Annette E. Allen, Robert J. Lucas
First page: 577
Abstract: Light is an influential regulator of behavioural and physiological state in mammals. Features of cognitive performance such as memory, vigilance and alertness can be altered by bright light exposure under laboratory and field conditions. However, the importance of light as a regulator of performance in everyday life is hard to assess and has so far remained largely unclear. We set out to address this uncertainty by developing a tool to capture measures of cognitive performance and light exposure, at scale, and during everyday life. To this end, we generated an app (Brighter Time) which incorporated a psychomotor vigilance (PVT), an N-back and a visual search task with questionnaire-based assessments of demographic characteristics, general health, chronotype and sleep. The app also measured illuminance during task completion using the smartphone’s intrinsic light meter. We undertook a pilot feasibility study of Brighter Time based on 91-week-long acquisition phases within a convenience sample (recruited by local advertisements and word of mouth) running Brighter Time on their own smartphones over two study phases in winter and summer. Study compliance was suitable (median = 20/21 requested task completions per subject). Statistically significant associations were observed between subjective sleepiness and performance in all tasks. Significant daily variations in PVT and visual search performance were also observed. Higher illuminance was associated with reduced reaction time and lower inverse efficiency score in the visual search. Brighter Time thus represents a viable option for large-scale collection of cognitive task data in everyday life, and is able to reveal associations between task performance and sleepiness, time of day and current illuminance. Brighter Time’s utility could be extended to exploring associations with longer-term patterns of light exposure and/or other light metrics by integrating with wearable light meters.
Citation: Clocks & Sleep
PubDate: 2022-10-21
DOI: 10.3390/clockssleep4040045
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 595-606: Associations among Alcohol
Drinking, Smoking, and Nonrestorative Sleep: A Population-Based Study in
Japan
Authors: Yuichiro Otsuka, Ohki Takeshima, Osamu Itani, Yuuki Matsumoto, Yoshitaka Kaneita
First page: 595
Abstract: Nonrestorative sleep (NRS) is a common sleep disorder. It is associated with several unhealthy lifestyle factors, such as skipping breakfast and lack of exercise. However, the associations between alcohol drinking, smoking, and NRS are unclear. This study examined the prevalence of NRS within the Japanese general population and the relationships among alcohol drinking, smoking, and NRS. We analyzed an anonymized dataset from a 2013 nationwide population survey (35,717 men and 39,911 women). NRS was assessed through a single-item question, and socio-demographic and lifestyle factors were assessed through self-reports. Multivariable logistic regression analyses were used to examine the associations between alcohol drinking, smoking, and NRS. The total prevalence of NRS was 22.2% (95% CI 21.8–22.7) in men and 23.4% (95% CI 23.0–23.8) in women. Further, we found that sleep duration and prevalence of NRS shared an inverse J-shaped relationship. Heavy alcohol drinking was significantly associated with NRS in both sexes. Short sleep duration and certain socioeconomic factors modified the effect of smoking on NRS in men. These results could be useful in the development of more effective sleep health policies to establish better sleep hygiene.
Citation: Clocks & Sleep
PubDate: 2022-10-24
DOI: 10.3390/clockssleep4040046
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 607-622: Impact of Evening Light Exposures
with Different Solid Angles on Circadian Melatonin Rhythms, Alertness, and
Visual Comfort in an Automotive Setting
Authors: Michael Weng, Isabel Schöllhorn, Maryia Kazhura, Brian B. Cardini, Oliver Stefani
First page: 607
Abstract: Future automotive interior lighting might have the potential to go beyond decorative purposes by influencing alertness, circadian physiology, and sleep. As the available space in the interior of an automobile for lighting applications is limited, understanding the impact of various luminous surface sizes on non-image-forming effects is fundamental in this field. In a laboratory study using a within-subject design, 18 participants were exposed to two bright light conditions with different solid angles and one dim light condition in a balanced, randomized order during the course of the evening. Our results demonstrate that both light conditions significantly increased subjective alertness and reduced salivary melatonin concentration but not cognitive performance compared to dim light. The solid angle of light exposure at constant corneal illuminance only affected visual comfort. While subjective alertness can be increased and melatonin can be attenuated with rather small luminaires, larger solid angles should be considered if visual comfort is a priority.
Citation: Clocks & Sleep
PubDate: 2022-10-26
DOI: 10.3390/clockssleep4040047
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 623-632: Recovery Sleep Immediately after
Prolonged Sleep Deprivation Stimulates the Transcription of Integrated
Stress Response-Related Genes in the Liver of Male Rats
Authors: Keisuke Fukuoka, Yusuke Murata, Tomomi Otomaru, Masayoshi Mori, Kenji Ohe, Kazunori Mine, Munechika Enjoji
First page: 623
Abstract: Sleep loss induces performance impairment and fatigue. The reactivation of human herpesvirus-6, which is related to the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), is one candidate for use as an objective biomarker of fatigue. Phosphorylated eIF2α is a key regulator in integrated stress response (ISR), an intracellular stress response system. However, the relation between sleep/sleep loss and ISR is unclear. The purpose of the current study was to evaluate the effect of prolonged sleep deprivation and recovery sleep on ISR-related gene expression in rat liver. Eight-week-old male Sprague–Dawley rats were subjected to a 96-hour sleep deprivation using a flowerpot technique. The rats were sacrificed, and the liver was collected immediately or 6 or 72 h after the end of the sleep deprivation. RT-qPCR was used to analyze the expression levels of ISR-related gene transcripts in the rat liver. The transcript levels of the Atf3, Ddit3, Hmox-1, and Ppp15a1r genes were markedly increased early in the recovery sleep period after the termination of sleep deprivation. These results indicate that both activation and inactivation of ISRs in the rat liver occur simultaneously in the early phase of recovery sleep.
Citation: Clocks & Sleep
PubDate: 2022-11-09
DOI: 10.3390/clockssleep4040048
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 633-657: Impact of Solid State Roadway
Lighting on Melatonin in Humans
Authors: Ronald B. Gibbons, Rajaram Bhagavathula, Benjamin Warfield, George C. Brainard, John P. Hanifin
First page: 633
Abstract: Introduction: In 2009, the World Health Organization identified vehicle crashes, both injury-related and fatal, as a public health hazard. Roadway lighting has long been used to reduce crashes and improve the safety of all road users. Ocular light exposure at night can suppress melatonin levels in humans. At sufficient light levels, all visible light wavelengths can elicit this response, but melatonin suppression is maximally sensitive to visible short wavelength light. With the conversion of roadway lighting to solid state sources that have a greater short wavelength spectrum than traditional sources, there is a potential negative health impact through suppressed melatonin levels to roadway users and those living close to the roadway. This paper presents data on the impact of outdoor roadway lighting on salivary melatonin in three cohorts of participants: drivers, pedestrians, and those experiencing light trespass in their homes. Methods: In an outdoor naturalistic roadway environment, healthy participants (N = 29) each being assigned to a cohort of either pedestrian, driver, or light trespass experiment, were exposed to five different solid state light sources with differing spectral emissions and one no lighting condition. Salivary melatonin measurements were made under an average roadway luminance of 1.0 cd/m2 (IES RP-18 Roadway Lighting Requirements for expressway roads) with a corneal melanopic Equivalent Daylight Illuminances (EDI) ranging from 0.22 to 0.86 lux. Results: The results indicate that compared to the no roadway lighting condition, the roadway light source spectral content did not significantly impact salivary melatonin levels in the participants in any of the cohorts. Conclusions: These data show that recommended levels of street lighting for expressway roads do not elicit an acute suppression of salivary melatonin and suggest that the health benefit of roadway lighting for traffic safety is not compromised by an acute effect on salivary melatonin.
Citation: Clocks & Sleep
PubDate: 2022-11-18
DOI: 10.3390/clockssleep4040049
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 658-674: Differences in Sleep Offset Timing
between Weekdays and Weekends in 79,161 Adult Participants in the UK
Biobank
Authors: Rachael M. Kelly, John H. McDermott, Andrew N. Coogan
First page: 658
Abstract: Variability in the timing of daily sleep is increasingly recognized as an important factor in sleep and general physical health. One potential driver of such daily variations in sleep timing is different work and social obligations during the “working week” and weekends. To investigate the nature of weekday/weekend differences in the timing of sleep offset, we examined actigraphy records of 79,161 adult participants in the UK Biobank who wore an actiwatch for 1 week. The time of sleep offset was found to be on average 36 min later on weekends than on weekdays, and when this difference was expressed as an absolute value (i.e., irrespective of sleep offset being either later or earlier on weekends), it was 63 min. Younger age, more socioeconomic disadvantage, currently being in employment, being a smoker, being male, being of non-white ethnicity and later chronotype were associated with greater differences in sleep offset between weekdays and weekend days. Greater differences in sleep offset timing were associated with age-independent small differences in cardiometabolic health indicators of BMI and diastolic blood pressure, but not HbA1c or systolic blood pressure. In a subset of participants with Type 2 Diabetes Mellitus, weekday/weekend sleep offset differences were associated weakly with BMI, systolic blood pressure and physical activity. Overall, this study demonstrates potentially substantive differences in sleep offset timings between weekdays and weekends in a large sample of UK adults, and that such differences may have public health implications.
Citation: Clocks & Sleep
PubDate: 2022-11-22
DOI: 10.3390/clockssleep4040050
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 675-687: The Effectiveness of
Blue-Light-Emitting Glasses in Security Guards Exposed to Night Shift Work
on Work-Related and General Fatigue: A Randomised Controlled Cross-Over
Study
Authors: Pieter H. Helmhout, Stella Timmerman, Alwin van Drongelen, Eric W. P. Bakker
First page: 675
Abstract: This study aimed to evaluate the effectiveness of glasses that emit blue light in reducing the need for recovery, general fatigue, and stress levels in security guards who work night shifts. Light manipulation is seen as a promising strategy to mitigate complaints related to shift work, such as sleepiness and impaired cognitive performance. In a randomized controlled cross-over study design, 86 Dutch security guards used light-emitting glasses (exposure duration: 30 min) during night shifts in a five week period versus a five week control period without glasses. Measurements (Need for Recovery Scale; Checklist Individual Strength; stress level assessed by a fitness tracker) were performed at baseline, at five weeks, and again at 11 weeks. The chronotype was measured at baseline as a potential covariate. A mixed model for repeated measure analyses showed no significant reduction in the need for recovery, nor a reduction in general fatigue scores, during the intervention period. Paired Samples T-Test analyses showed no significant changes in stress levels for the intervention period. Conclusively, blue light exposure using light-emitting glasses for security guards during night shifts showed no directly measurable effect on the reduced need for recovery, overall fatigue, and stress levels.
Citation: Clocks & Sleep
PubDate: 2022-11-24
DOI: 10.3390/clockssleep4040051
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 688-713: Maternal Sleep Problems in the
Periconceptional Period and the Impact on Health of Mother and Offspring:
A Systematic Review
Authors: Babette Bais, Milan G. Zarchev, Annemarie I. Luik, Lenie van Rossem, Régine P. M. Steegers-Theunissen
First page: 688
Abstract: Knowledge of the impact of sleep problems in the periconceptional period is scarce. Since this period is the most sensitive time window for embryonic and placental development, we aim to study the impact of maternal sleep problems in the periconceptional period on both mother and offspring. We systematically searched various databases up until September 2021 for studies reporting on maternal sleep in the periconceptional period and any outcome in mother and offspring. We included observational studies describing maternal sleep problems in the periconceptional period and associations with either maternal and/or offspring outcomes. The search produced 8596 articles, of which we selected 27 studies. Some associations were found between sleep problems and lower fertility, more hypertensive disorders, more mood disorders in mothers, higher risk of preterm birth and low birth weight, and more sleep and behavior problems in offspring, with associations with maternal mood disorders being most consistent. This systematic review shows that maternal sleep problems in the periconceptional period are associated with a higher risk of various adverse outcomes in both mother and offspring, although not consistently. It shows that good sleep during pregnancy is crucial, starting as early as before conception, especially for maternal mood. Therefore, it is important for clinicians to pay attention to sleep problems in the periconceptional period and provide adequate treatment for potential sleep problems, even before pregnancy.
Citation: Clocks & Sleep
PubDate: 2022-11-24
DOI: 10.3390/clockssleep4040052
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 714-721: Interest Groups as an Alternative
for Medical Education in Sleep Medicine: Experience Report at a Brazilian
Medical School
Authors: Vitor Luiz Selva Pinto, Guilherme El-Kadre, Henrique Lobo Ramos, Lucas Boaventura Pinto, Victor Davis Apostolakis Malfatti, Paula Araujo, Sandra Doria Xavier, Gabriel Natan Pires
First page: 714
Abstract: Sleep medicine classes and teachings are usually deficient and insufficient during undergraduate medical education. In order to circumvent the educational deficits in sleep medicine, students at a Brazilian Medical School created a sleep medicine interest group—an academic organization for teaching purposes whose administration is carried out by the undergraduate students themselves. This study aims to describe the establishment of a sleep medicine interest group, as well as to evaluate the results of its first edition on the knowledge about sleep medicine among undergraduate medical students. Classes were taken biweekly and consisted of lectures by invited professors, presentation of clinical cases, and discussion with the students. By the end of the course, both attendees and non-attendees were invited to fill out a questionnaire including an objective assessment of knowledge (15 multiple choice questions). The questionnaire was filled out by 32 participants, of which 18 were attendees and 14 were non-attendees. The average result on the final exam was significantly higher among the attendees (6.1 ± 1.2) in comparison with non-attendees (4.9 ± 1.3—p = 0.015). The results demonstrate that an interest group proved to be feasible as a source of complementary information to undergraduate medical students and a valid alternative to circumvent the educational deficits.
Citation: Clocks & Sleep
PubDate: 2022-11-25
DOI: 10.3390/clockssleep4040053
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 722-734: Mild to Moderate Sleep Restriction
Does Not Affect the Cortisol Awakening Response in Healthy Adult Males
Authors: Thomas G. Kontou, Gregory D. Roach, Charli Sargent
First page: 722
Abstract: The cortisol awakening response (CAR) is a distinct rise in cortisol that occurs upon awakening that is thought to contribute to arousal, energy boosting, and anticipation. There is some evidence to suggest that inadequate sleep may alter the CAR, but the relationship between sleep duration and CAR has not been systematically examined. Healthy males (n = 111; age: 23.0 ± 3.6 yrs) spent 10 consecutive days/nights in a sleep laboratory. After a baseline night (9 h time in bed), participants spent either 5 h (n = 19), 6 h (n = 23), 7 h (n = 16), 8 h (n = 27), or 9 h (n = 26) in bed for seven nights, followed by a 9 h recovery sleep. The saliva samples for cortisol assay were collected at 08:00 h, 08:30 h and 08:45 h at baseline, on experimental days 2 and 5 and on the recovery day. The primary dependent variables were the cortisol concentration at awakening (08:00 h) and the cortisol area under the curve (AUC). There was no effect of time in bed on either the cortisol concentration at awakening or cortisol AUC. In all the time in bed conditions, the cortisol AUC tended to be higher at baseline and lower on experimental day 5. Five consecutive nights of mild to moderate sleep restriction does not appear to affect the CAR in healthy male adults.
Citation: Clocks & Sleep
PubDate: 2022-11-25
DOI: 10.3390/clockssleep4040054
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 735-744: Clinical Evaluation and Management
of Overlap Syndrome (OS) and Obesity Hypoventilation Syndrome (OHS)
Authors: Pasquale Tondo, Giulia Scioscia, Anela Hoxhallari, Roberto Sabato, Simone Sorangelo, Giuseppe Mansueto, Antonella Giuliani, Maria Pia Foschino Barbaro, Donato Lacedonia
First page: 735
Abstract: Background and Aim: Sleep-disordered breathing (SDB) is an extremely common disorder with a high impact on morbidity and mortality. The purpose of this study was to compare overlap syndrome (OS) and obesity hypoventilation syndrome (OHS) and to highlight and understand the differences between them. Material and Methods: The study was conducted retrospectively on 132 subjects selected by consecutive sampling from those attending our unit for suspected SDB. After clinical evaluation as well as functional and sleep investigations, the population was divided according to diagnosis in OS and OHS; then, the clinical parameters of two groups were compared with different statistical analysis. Results: The subjects with OHS were younger and reported higher rated daytime sleepiness (p = 0.005). In addition, they presented more nocturnal respiratory events (apnea-hypopnea index (AHI) 63.61 ± 22.79 events·h−1 vs. AHIOS 42.21 ± 22.91 events·h−1, p < 0.0001) at the sleep investigation as worse gas exchange during sleep leading to a higher percentage of nocturnal hypoxemia (p < 0.0001). In contrast, subjects with OS had more an impaired respiratory function. With regard to night-time ventilatory therapy, more subjects with OS were effectively treated with continuous positive airway pressure (CPAP) (p = 0.011), while more OHS were treated with auto-adjusting PAP (APAP) (14% vs. 1%, p = 0.008). Conclusions: The present study tried to establish a framework for OS and OHS because proper management of the two disorders would reduce their burden on healthcare.
Citation: Clocks & Sleep
PubDate: 2022-12-06
DOI: 10.3390/clockssleep4040055
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 745-760: Characteristic of Ultrastructure of
Authors: D. A. Areshidze, M. A. Kozlova, V. P. Chernikov, A. V. Borisov, D. V. Mischenko
First page: 745
Abstract: Circadian rhythms of physiological processes, constantly being in a state of dynamic equilibrium and plastically associated with changes in environmental conditions, are the basis of homeostasis of an organism of human and other mammals. Violation of circadian rhythms due to significant disturbances in parameters of main environmental effectors (desynchronosis) leads to the development of pathological conditions and a more severe course of preexisting pathologies. We conducted the study of the ultrastructure of cells of mice transplantable malignant melanoma B16 under the condition of normal (fixed) lighting regime and under the influence of constant lighting. Results of the study show that melanoma B16 under fixed light regime represents a characteristic picture of this tumor—predominantly intact tissue with safe junctions of large, functionally active cells with highly irregular nuclei, developed organelles and a relatively low content of melanin. The picture of the B16 melanoma tissue structure and the ultrastructure of its cells under the action of constant lighting stand in marked contrast to the group with fixed light: under these conditions the tumor exhibits accelerated growth, a significant number of cells in the state of apoptosis and necrosis, ultrastructural signs of degradation of the structure and functions, and signs of embryonization of cells with the background of adaptation to oxygen deficiency.
Citation: Clocks & Sleep
PubDate: 2022-12-15
DOI: 10.3390/clockssleep4040056
Issue No: Vol. 4, No. 4 (2022)
- Clocks & Sleep, Vol. 4, Pages 321-331: Adipokines in Sleep Disturbance and
Metabolic Dysfunction: Insights from Network Analysis
Authors: Zhikui Wei, You Chen, Raghu P. Upender
First page: 321
Abstract: Adipokines are a growing group of secreted proteins that play important roles in obesity, sleep disturbance, and metabolic derangements. Due to the complex interplay between adipokines, sleep, and metabolic regulation, an integrated approach is required to better understand the significance of adipokines in these processes. In the present study, we created and analyzed a network of six adipokines and their molecular partners involved in sleep disturbance and metabolic dysregulation. This network represents information flow from regulatory factors, adipokines, and physiologic pathways to disease processes in metabolic dysfunction. Analyses using network metrics revealed that obesity and obstructive sleep apnea were major drivers for the sleep associated metabolic dysregulation. Two adipokines, leptin and adiponectin, were found to have higher degrees than other adipokines, indicating their central roles in the network. These adipokines signal through major metabolic pathways such as insulin signaling, inflammation, food intake, and energy expenditure, and exert their functions in cardiovascular, reproductive, and autoimmune diseases. Leptin, AMP activated protein kinase (AMPK), and fatty acid oxidation were found to have global influence in the network and represent potentially important interventional targets for metabolic and sleep disorders. These findings underscore the great potential of using network based approaches to identify new insights and pharmaceutical targets in metabolic and sleep disorders.
Citation: Clocks & Sleep
PubDate: 2022-06-22
DOI: 10.3390/clockssleep4030027
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 332-345: Noradrenergic Signaling in
Astrocytes Influences Mammalian Sleep Homeostasis
Authors: Ashley M. Ingiosi, Marcos G. Frank
First page: 332
Abstract: Astrocytes influence sleep expression and regulation, but the cellular signaling pathways involved in these processes are poorly defined. We proposed that astrocytes detect and integrate a neuronal signal that accumulates during wakefulness, thereby leading to increased sleep drive. Noradrenaline (NA) satisfies several criteria for a waking signal integrated by astrocytes. We therefore investigated the role of NA signaling in astrocytes in mammalian sleep. We conditionally knocked out (cKO) β2-adrenergic receptors (β2-AR) selectively in astrocytes in mice and recorded electroencephalographic and electromyographic activity under baseline conditions and in response to sleep deprivation (SDep). cKO of astroglial β2-ARs increased active phase siesta duration under baseline conditions and reduced homeostatic compensatory changes in sleep consolidation and non-rapid eye movement slow-wave activity (SWA) after SDep. Overall, astroglial NA β2-ARs influence mammalian sleep homeostasis in a manner consistent with our proposed model of neuronal–astroglial interactions.
Citation: Clocks & Sleep
PubDate: 2022-07-07
DOI: 10.3390/clockssleep4030028
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 346-357: Prediction of Dropout in a
Randomized Controlled Trial of Adjunctive Light Treatment in Patients with
Non-Seasonal Depression and Evening Chronotype
Authors: Joey W.Y. Chan, Shirley Xin Li, Steven Wai Ho Chau, Ngan Yin Chan, Jihui Zhang, Yun Kwok Wing
First page: 346
Abstract: The current study examined the possible predictors of dropout during a five-week light treatment (LT) with a gradual advance protocol in 93 patients with unipolar non-seasonal depression and evening chronotypes by comparing their clinical characteristics and performing a logistic regression analysis. Nineteen out of ninety-three (20%) subjects (80% female, 46.5 ± 11.7 years old) dropped out during the 5-week light treatment. Treatment non-adherence (i.e., receiving LT for less than 80% of the prescribed duration) over the first treatment week predicted a five-fold increase in risk of dropout during light therapy (OR: 5.85, CI: 1.41–24.21) after controlling for potential confounders, including age, gender, treatment group, rise time at the baseline, patient expectation, and treatment-emergent adverse events. There is a need to incorporate strategies to enhance treatment adherence and retention in both research and clinical settings. Chinese clinical trial registry (ChiCTR-IOR-15006937).
Citation: Clocks & Sleep
PubDate: 2022-07-27
DOI: 10.3390/clockssleep4030029
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 358-373: The Effect of Light Therapy on
Electroencephalographic Sleep in Sleep and Circadian Rhythm Disorders: A
Scoping Review
Authors: Teha B. Pun, Craig L. Phillips, Nathaniel S. Marshall, Maria Comas, Camilla M. Hoyos, Angela L. D’Rozario, Delwyn J. Bartlett, Wendy Davis, Wenye Hu, Sharon L. Naismith, Sean Cain, Svetlana Postnova, Ron R. Grunstein, Christopher J. Gordon
First page: 358
Abstract: Light therapy is used to treat sleep and circadian rhythm disorders, yet there are limited studies on whether light therapy impacts electroencephalographic (EEG) activity during sleep. Therefore, we aimed to provide an overview of research studies that examined the effects of light therapy on sleep macro- and micro-architecture in populations with sleep and circadian rhythm disorders. We searched for randomized controlled trials that used light therapy and included EEG sleep measures using MEDLINE, PubMed, CINAHL, PsycINFO and Cochrane Central Register of Controlled Trials databases. Five articles met the inclusion criteria of patients with either insomnia or delayed sleep–wake phase disorder (DSWPD). These trials reported sleep macro-architecture outcomes using EEG or polysomnography. Three insomnia trials showed no effect of the timing or intensity of light therapy on total sleep time, wake after sleep onset, sleep efficiency and sleep stage duration compared to controls. Only one insomnia trial reported significantly higher sleep efficiency after evening light therapy (>4000 lx between 21:00–23:00 h) compared with afternoon light therapy (>4000 lx between 15:00–17:00 h). In the only DSWPD trial, six multiple sleep latency tests were conducted across the day (09:00 and 19:00 h) and bright light (2500 lx) significantly lengthened sleep latency in the morning (09:00 and 11:00 h) compared to control light (300 lx). None of the five trials reported any sleep micro-architecture measures. Overall, there was limited research about the effect of light therapy on EEG sleep measures, and studies were confined to patients with insomnia and DSWPD only. More research is needed to better understand whether lighting interventions in clinical populations affect sleep macro- and micro-architecture and objective sleep timing and quality.
Citation: Clocks & Sleep
PubDate: 2022-08-09
DOI: 10.3390/clockssleep4030030
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 374-380: NREM Parasomnias: Retrospective
Analysis of Treatment Approaches and Comorbidities
Authors: Naina Limbekar, Jonathan Pham, Rohit Budhiraja, Sogol Javaheri, Lawrence J. Epstein, Salma Batool-Anwar, Milena Pavlova
First page: 374
Abstract: The aim of this retrospective analysis is to determine the most frequently prescribed medications for the treatment of NREM parasomnias and evaluate reported outcomes. We performed a retrospective chart review of all patients with NREM parasomnia diagnosed within Brigham and Women’s Hospital (BWH) clinics examining the date of diagnosis, date of starting therapy, comorbidities, type of medication prescribed, and the reported change in symptoms or side effects at follow-up visits. From 2012 to 2019, 110 patients (59 females, 51 male) at BWH clinics received a diagnosis of NREM parasomnia, including sleepwalking and night terrors. The mean age was 44. Comorbidities included obstructive sleep apnea (OSA) (46%), periodic limb movement syndrome (PLMS) (13%), insomnia (19%), Restless leg syndrome (RLS) (9%), epilepsy (4%), and REM behavior disorder (RBD) (9%). Initial treatment strategies include behavioral and safety counseling only (34%), pharmacological treatment (29%), treatment of any comorbidity (28%), and combined treatment of any of the above (9%). Improvement was reported with: treatment of OSA (n = 23 52% reported improvement), melatonin (n = 8, improvement reported by 88%.,benzodiazepine (n = 7, improvement reported by 57%). Treating comorbid conditions is a frequent treatment strategy, often associated with symptom improvement. The pharmacologic treatment most commonly included melatonin and benzodiazepines. Comprehensive management should include behavioral and safety recommendations, assessment of comorbid conditions, and individually tailored pharmaceutical treatment.
Citation: Clocks & Sleep
PubDate: 2022-08-16
DOI: 10.3390/clockssleep4030031
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 381-386: Time Course of Motor Activity Wake
Inertia Dissipation According to Age
Authors: Lorenzo Tonetti, Miranda Occhionero, Marco Fabbri, Sara Giovagnoli, Martina Grimaldi, Monica Martoni, Vincenzo Natale
First page: 381
Abstract: The time course of motor activity sleep inertia (maSI) dissipation was recently investigated through actigraphy in an everyday life condition from middle childhood to late adulthood. Motor activity sleep inertia was dissipated in 70 min, and the sleep inertia phenomenon was more evident in younger participants than in older participants. The aim of the current secondary analysis of previously published data was to examine, within the same sample, the time course of motor activity wake inertia (maWI) dissipation, i.e., the motor pattern in the transition phase from wakefulness to sleep, according to age. To this end, an overall sample of 374 participants (215 females), ranging in age between 9 and 70 years old, was examined. Each participant was asked to wear an actigraph around their non-dominant wrist for one week. The variation in the motor activity pattern of the wake–sleep transition according to age was examined through functional linear modeling (FLM). FLM showed that motor activity wake inertia dissipated around 20 min after bedtime. Moreover, a lower age was significantly associated with greater motor activity within the last two hours of wakefulness and the first twenty minutes after bedtime. Overall, this pattern of results seems to suggest that maWI dissipation is comparable to that of maSI.
Citation: Clocks & Sleep
PubDate: 2022-08-30
DOI: 10.3390/clockssleep4030032
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 387-401: Potential Benefits of Daytime Naps
on Consecutive Days for Motor Adaptation Learning
Authors: Yusuke Murata, Masaki Nishida, Atsushi Ichinose, Shutaro Suyama, Sumi Youn, Kohei Shioda
First page: 387
Abstract: Daytime napping offers benefits for motor memory learning and is used as a habitual countermeasure to improve daytime functioning. A single nap has been shown to ameliorate motor memory learning, although the effect of consecutive napping on motor memory consolidation remains unclear. This study aimed to explore the effect of daytime napping over multiple days on motor memory learning. Twenty university students were divided into a napping group and no-nap (awake) group. The napping group performed motor adaption tasks before and after napping for three consecutive days, whereas the no-nap group performed the task on a similar time schedule as the napping group. A subsequent retest was conducted one week after the end of the intervention. Significant differences were observed only for speed at 30 degrees to complete the retention task, which was significantly faster in the napping group than in the awake group. No significant consolidation effects over the three consecutive nap intervention periods were confirmed. Due to the limitations of the different experimental environments of the napping and the control group, the current results warrant further investigation to assess whether consecutive napping may benefit motor memory learning, which is specific to speed.
Citation: Clocks & Sleep
PubDate: 2022-08-30
DOI: 10.3390/clockssleep4030033
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 402-411: Dreaming and Sleep-Related
Metacognitions in Patients with Sleep Disorders
Authors: Michael Schredl, Claudia Schilling
First page: 402
Abstract: Sleep-related metacognitions play a role in the etiology of insomnia and are distressing while falling asleep. Although similar concepts, such as thought suppression, have been studied in the context of dreaming, the relationship between sleep-related metacognitions and more negatively toned dreaming due to stressful pre-sleep experiences has yet to be studied. Overall, 919 patients with various sleep disorders completed the Metacognitions Questionnaire-Insomnia (MCQ-I20), Arousal Disposition Scale (APS), and Pre-Sleep Arousal Scale (PSAS) and kept a sleep diary over seven days eliciting dream recall, nightmare frequency, and the emotional tone of their dreams. The regression analysis showed that the MCQ-I20 (small effect size) and the APS (medium effect size) were associated with nightmare frequency and negatively toned dream emotions. These findings suggest that dysfunctional sleep-related metacognitions that are active prior to sleep are also associated with more negatively toned dreaming and more nightmares—even after controlling for trait arousability. It would be very interesting to study where therapeutic strategies, such as metacognitive therapy explicitly targeting sleep-related metacognition, could also be beneficial with regard to dreams (more positive dreams and fewer nightmares).
Citation: Clocks & Sleep
PubDate: 2022-09-01
DOI: 10.3390/clockssleep4030034
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 412-460: 33rd Annual Meeting of the Society
for Light Treatment and Biological Rhythms (SLTBR), 23–25 June 2022,
Manchester, UK
Authors: Marijke Gordijn
First page: 412
Abstract: The 33rd annual meeting of the Society for Light Treatment and Biological Rhythms was held in Manchester in June 2022 [...]
Citation: Clocks & Sleep
PubDate: 2022-09-02
DOI: 10.3390/clockssleep4030035
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 458-465: Effects of One Night of Forced
Wakefulness on Morning Resting Blood Pressure in Humans: The Role of
Biological Sex and Weight Status
Authors: Lieve T. van Egmond, Pei Xue, Elisa M. S. Meth, Maria Ilemosoglou, Joachim Engström, Christian Benedict
First page: 458
Abstract: Permanent night shift work is associated with adverse health effects, including elevated blood pressure (BP) and hypertension. Here, we examined the BP response to one night of forced wakefulness in a sitting position in a cohort without night shift work experience. According to a counterbalanced crossover design, 47 young adults with either obesity (N = 22; 10 women) or normal weight (N = 25; 11 women) participated in one night of sleep and one night of forced wakefulness under in-laboratory conditions. Resting ankle and brachial arterial BP were assessed in the morning, i.e., the time of the day when adverse cardiovascular events peak. After forced wakefulness, diastolic and mean arterial BP were ~4 mmHg higher at the ankle site and ~3 mmHg higher at the brachial site than after regular sleep (p < 0.05). The increase in BP following overnight forced wakefulness was more pronounced among men vs. women and more significant for diastolic BP at both sites among participants with normal weight vs. those with obesity. If confirmed in larger cohorts, including 24 h BP monitoring, people with occupations involving night shifts might benefit from regular BP monitoring. Particular attention should be paid to possible sex- and weight-specific effects of night shift work on BP.
Citation: Clocks & Sleep
PubDate: 2022-09-14
DOI: 10.3390/clockssleep4030036
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 466-474: Diurnal Preference and Correlates
of Multidimensional Perfectionism, Type-D Personality, and Big Five
Personality Traits
Authors: Jodie C. Stevenson, Anna Johann, Asha Akram, Sarah Allen, Umair Akram
First page: 466
Abstract: This study examined the extent to which the dimensions of the five-factor model, Type-D personality, and multidimensional perfectionism were associated with a diurnal preference in the general population. A sample of (N = 864) individuals completed the measures of diurnal preference, multidimensional perfectionism, Type-D personality, and the Big Five traits. A correlational analysis determined that agreeableness, conscientiousness, emotional stability, organization, and personal standards were independently related to morningness. In contrast, negative affect, social inhibition, Type-D personality, and perfectionistic doubts and concerns, as well as an increased perception of critical parental evaluation, were independently related to eveningness. After accounting for the shared variance amongst the personality traits, only negative affect, conscientiousness, organization, personal standards, and parental perception were significantly associated with diurnal preference. The current outcomes offer further insight into the relationship between personality and diurnal preference. Here, we observed greater reports of adaptive personality traits in relation to morningness, whereas negative affect and perceived parental evaluation and criticism were related to eveningness. As the first study to examine the relationship between Type-D personality, multidimensional perfectionism, and diurnal preference, the current outcomes should be considered preliminary.
Citation: Clocks & Sleep
PubDate: 2022-09-14
DOI: 10.3390/clockssleep4030037
Issue No: Vol. 4, No. 3 (2022)
- Clocks & Sleep, Vol. 4, Pages 208-218: Direct Effects of Light on Sleep
under Ultradian Light-Dark Cycles Depend on Circadian Time and Pulses
Duration
Authors: Fanny Fuchs, Ludivine Robin-Choteau, Laurence Hugueny, Dominique Ciocca, Patrice Bourgin
First page: 208
Abstract: Ultradian light–dark cycles in rodents are a precious tool to study the direct effects of repeated light exposures on sleep, in order to better understand the underlying mechanisms. This study aims to precisely evaluate the effects of light and dark exposures, according to circadian time, on sleep and waking distribution and quality, and to determine if these effects depend on the duration of light and dark pulses. To do this, mice were exposed to 24 h-long ultradian light–dark cycles with different durations of pulses: T2 cycle (1 h of light/1 h of dark) and T7 cycle (3.5 h of light/3.5 h of dark). Exposure to light not only promotes NREM and REM sleep and inhibits wake, but also drastically alters alertness and modifies sleep depth. These effects are modulated by circadian time, appearing especially during early subjective night, and their kinetics is highly dependent on the duration of pulses, suggesting that in the case of pulses of longer duration, the homeostatic process could overtake light direct influence for shaping sleep and waking distribution.
Citation: Clocks & Sleep
PubDate: 2022-03-24
DOI: 10.3390/clockssleep4020019
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 219-229: Respiratory Muscle Training in
Patients with Obstructive Sleep Apnoea: A Systematic Review and
Meta-Analysis
Authors: Rodrigo Torres-Castro, Lilian Solis-Navarro, Homero Puppo, Victoria Alcaraz-Serrano, Luis Vasconcello-Castillo, Jordi Vilaró, Roberto Vera-Uribe
First page: 219
Abstract: Background: Effective treatments for obstructive sleep apnoea (OSA) include positive pressure, weight loss, oral appliances, surgery, and exercise. Although the involvement of the respiratory muscles in OSA is evident, the effect of training them to improve clinical outcomes is not clear. We aimed to determine the effects of respiratory muscle training in patients with OSA. Methods: A systematic review was conducted in seven databases. Studies that applied respiratory muscle training in OSA patients were reviewed. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence. Results: Of the 405 reports returned by the initial search, eight articles reporting on 210 patients were included in the data synthesis. Seven included inspiratory muscle training (IMT), and one included expiratory muscle training (EMT). Regarding IMT, we found significant improvement in Epworth sleepiness scale in −4.45 points (95%CI −7.64 to −1.27 points, p = 0.006), in Pittsburgh sleep quality index of −2.79 points (95%CI −4.19 to −1.39 points, p < 0.0001), and maximum inspiratory pressure of −29.56 cmH2O (95%CI −53.14 to −5.98 cmH2O, p = 0.01). However, the apnoea/hypopnea index and physical capacity did not show changes. We did not perform a meta-analysis of EMT due to insufficient studies. Conclusion: IMT improves sleepiness, sleep quality and inspiratory strength in patients with OSA.
Citation: Clocks & Sleep
PubDate: 2022-04-11
DOI: 10.3390/clockssleep4020020
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 230-239: Combining Wake-Up-Back-to-Bed with
Cognitive Induction Techniques: Does Earlier Sleep Interruption Reduce
Lucid Dream Induction Rate'
Authors: Daniel Erlacher, Vitus Furrer, Matthias Ineichen, John Braillard, Daniel Schmid
First page: 230
Abstract: Lucid dreaming offers the chance to investigate dreams from within a dream and by real-time dialogue between experimenters and dreamers during REM sleep. This state of consciousness opens a new experimental venue for dream research. However, laboratory study in this field is limited due to the rarity of lucid dreamers. In a previous study, we were able to induce in 50% of the participants a lucid dream in a single sleep laboratory night by combining a wake-up-back-to-bed (WBTB) sleep routine and a mnemonic method (Mnemonic Induction of Lucid Dreams, MILD). In three experiments, we tried to replicate our earlier findings while we adapted our procedure in shortening (Exp1–3: 4.5 vs. 6 h of uninterrupted sleep in the first half of the night), simplifying (Exp2: time-based wakening vs. REM wakening in the second half of the night), and applying another induction technique (Exp3: reality testing vs. MILD). In the three conditions, four out of 15 (26%), zero out of 20 (0%), and three out of 15 (20%) participants reported a lucid dream. Compared to the original study, the earlier sleep interruption seems to reduce the lucid dream induction rate. Furthermore, without REM awakenings in the morning, lucid dream induction failed, whereas reality testing showed a lower success rate compared to MILD. Further systematic sleep laboratory studies are needed to develop reliable techniques for lucid dream research.
Citation: Clocks & Sleep
PubDate: 2022-04-20
DOI: 10.3390/clockssleep4020021
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 240-259: Socioeconomic Position and
Excessive Daytime Sleepiness: A Systematic Review of Social
Epidemiological Studies
Authors: Imene Bendaoud, Faustin Armel Etindele Sosso
First page: 240
Abstract: The objectives of this empirical study are to describe and discuss the current literature available on the relationship between excessive daytime sleepiness (EDS) and the socioeconomic position (SEP) as well as to provide recommendations for consideration of SEP in sleep medicine and biomedical research. Databases Medline/PubMed, Web of Science, Google scholar and Scopus were screened from January 1990 to December 2020 using PRISMA guidelines and 20 articles were included in the final synthesis. Nineteen studies were cross-sectional and one study was longitudinal. Among these studies, 25.00% (n = 5) are focused on children and adolescent and the remaining 75.00% (n = 15) focused on adults and seniors. Ages ranged from 8 to 18 years old for children/adolescent and ranged from 18 to 102 years old for adults. Main SEP measures presented in these studies were education, income, perceived socioeconomic status and employment. The sample size in these studies varied from N = 90 participants to N = 33,865 participants. Overall, a lower educational level, a lower income and full-time employment were associated with EDS. Symptoms of EDS are prevalent in women, especially those with a low income or no job; and children and adolescents with difficult living conditions or working part time reported more sleep disturbances. SEP is already considered as an important determinant for many health outcomes, but if SEP is embedded in the experimental design in psychosomatic research, biomedical research and clinical practice as a constant variable regardless of outcome; it will move forward future investigations.
Citation: Clocks & Sleep
PubDate: 2022-05-16
DOI: 10.3390/clockssleep4020022
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 260-276: Long-Term Effect of a Single Dose
of Caffeine on Sleep, the Sleep EEG and Neuronal Activity in the
Peduncular Part of the Lateral Hypothalamus under Constant Dark Conditions
Authors: Yumeng Wang, Tom Deboer
First page: 260
Abstract: Background: Caffeine is a central nervous system stimulant that influences both the sleep–wake cycle and the circadian clock and is known to influence neuronal activity in the lateral hypothalamus, an important area involved in sleep–wake regulation. Light is a strong zeitgeber and it is known to interact with the effect of caffeine on the sleep–wake cycle. We therefore wanted to investigate the long-term effects of a single dose of caffeine under constant dark conditions. Methods: We performed long-term (2 days) electroencephalogram (EEG)/electromyogram recordings combined with multi-unit neuronal activity recordings in the peduncular part of the lateral hypothalamus (PLH) under constant darkness in Brown Norway rats, and investigated the effect of a single caffeine treatment (15 mg/kg) or saline control given 1 h after the onset of the endogenous rest phase. Results: After a reduction in sleep and an increase in waking and activity in the first hours after administration, also on the second recording day after caffeine administration, rapid eye movement (REM) sleep was still reduced. Analysis of the EEG showed that power density in the theta range during waking and REM sleep was increased for at least two days. Neuronal activity in PLH was also increased for two days after the treatment, particularly during non-rapid eye movement sleep. Conclusion: Surprisingly, the data reveal long-term effects of a single dose of caffeine on vigilance states, EEG, and neuronal activity in the PLH. The absence of a light–dark cycle may have enabled the expression of these long-term changes. It therefore may be that caffeine, or its metabolites, have a stronger and longer lasting influence, particularly on the expression of REM sleep, than acknowledged until now.
Citation: Clocks & Sleep
PubDate: 2022-05-25
DOI: 10.3390/clockssleep4020023
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 277-286: Effect of Modified
Yukmijihwang-Tang on Sleep Quality in the Rat
Authors: SunYoung Lee, Hun-Soo Lee, Minsook Ye, Min-A Kim, Hwajung Kang, Sung Ja Rhie, Mi Young Lee, In Chul Jung, In-Cheol Kang, Insop Shim
First page: 277
Abstract: Many plants have been used in Korean medicine for treating insomnia. However, scientific evidence for their sedative activity has not been fully investigated. Thus, this study was carried out to investigate the sedative effects of the extracts of medicinal plants, including Yukmijihwang-tang and its various modified forms through the 5-HT2c receptor binding assay, and to further confirm its sleep-promoting effects and the underlying neural mechanism in rats utilizing electroencephalography (EEG) analysis. Enzyme-linked immunosorbent assay (ELISA) was used to measure serotonin (5-HT) in the brain. The water extracts of modified Yukmijihwang-tang (YmP) displayed binding affinity to the 5-HT2C receptor (IC50 value of 199.9 µg/mL). YmP (50 mg/kg) administration decreased wake time and increased REM and NREM sleep based on EEG data in rats. Additionally, treatment with YmP significantly increased the 5-HT level in the hypothalamus. In conclusion, the sedative effect of YmP can be attributed to the activation of the central serotonergic systems, as evidenced by the high affinity of binding of the 5-HT2C receptor and increased 5-HT levels in the brain of the rat. This study suggests that YmP can be a new material as a sleep inducer in natural products.
Citation: Clocks & Sleep
PubDate: 2022-05-27
DOI: 10.3390/clockssleep4020024
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 287-299: Neuroimaging in the Rare Sleep
Disorder of Kleine–Levin Syndrome: A Systematic Review
Authors: Juan Fernando Ortiz, Jennifer M. Argudo, Mario Yépez, Juan Andrés Moncayo, Hyder Tamton, Alex S. Aguirre, Ghanshyam Patel, Meghdeep Sen, Ayushi Mistry, Ray Yuen, Ahmed Aeissa Garces, Diego Ojeda, Samir Ruxmohan
First page: 287
Abstract: Kleine–Levin syndrome (KLS) is characterized by episodes of hypersomnia. Additionally, these patients can present with hyperphagia, hypersexuality, abnormal behavior, and cognitive dysfunction. Functional neuroimaging studies such as fMRI-BOLD, Positron Emission Tomography (PET) or SPECT help us understand the neuropathological bases of different disorders. We conducted a systematic review to investigate the neuroimaging features of KLS patients and their clinical correlations. This systematic review was conducted by following the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) and PRISMA protocol reporting guidelines. We aim to investigate the clinical correlation with neuroimaging among patients with KLS. We included only studies written in the English language in the last 20 years, conducted on humans; 10 studies were included. We excluded systematic reviews, metanalysis, and case reports. We found that there are changes in functional imaging studies during the symptomatic and asymptomatic periods as well as in between episodes in patients with K.L.S. The areas most reported as affected were the hypothalamic and thalamic regions, which showed hypoperfusion and, in a few cases, hyperperfusion; areas such as the frontal, parietal, occipital and the prefrontal cortex all showed alterations in cerebral perfusion. These changes in cerebral blood flow and regions vary according to the imaging (SPECT, PET SCAN, or fMRI) and the task performed while imaging was performed. We encountered conflicting data between studies. Hyper insomnia, the main feature of this disease during the symptomatic periods, was associated with decreased thalamic activity. Other features of K.L.S., such as apathy, hypersexuality, and depersonalization, were also correlated with functional imaging changes. There were also findings that correlated with working memory deficits seen in this stage during the asymptomatic periods. Hyperactivity of the thalamus and hypothalamus were the main features shown during the asymptomatic period. Additionally, functional imaging tends to improve with a longer course of the disease, which suggests that K.L.S. patients outgrow the disease. These findings should caution physicians when analyzing and correlating neuroimaging findings with the disease.
Citation: Clocks & Sleep
PubDate: 2022-05-31
DOI: 10.3390/clockssleep4020025
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 300-320: 2021 Annual Meeting of the Swiss
Society for Sleep Research, Sleep Medicine, and Chronobiology (SSSSC)
Authors: Martin Hatzinger
First page: 300
Abstract: The 2021 meeting in Solothurn provided evidence-based education to advance the science and clinical practice of sleep medicine and sleep physiology, disseminates cutting-edge sleep and circadian research, promotes the translation of basic science into clinical practice, and fosters the future of the field by allowing young clinicians and researchers to present their findings in talks and on posters [...]
Citation: Clocks & Sleep
PubDate: 2022-06-07
DOI: 10.3390/clockssleep4020026
Issue No: Vol. 4, No. 2 (2022)
- Clocks & Sleep, Vol. 4, Pages 8: Acknowledgment to Reviewers of Clocks
& Sleep in 2021
Authors: Clocks & Sleep Editorial Office Clocks & Sleep Editorial Office
First page: 8
Abstract: Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Citation: Clocks & Sleep
PubDate: 2022-01-27
DOI: 10.3390/clockssleep4010002
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 9-15: Dream Recall/Affect and Cortisol:
An Exploratory Study
Authors: Alexandros S. Triantafyllou, Ioannis Ilias, Nicholas-Tiberio Economou, Athina Pappa, Eftychia Koukkou, Paschalis Steiropoulos
First page: 9
Abstract: The effect of cortisol on dreams has been scarcely studied. The aim of this exploratory study was to assess the possible effect of cortisol levels on dream recall/affect, considering, in female subjects, their menstrual cycle phase. Fifteen men and fifteen women were recruited. Saliva samples were used for the detection of cortisol levels. Participants were instructed to provide four saliva samples, during three consecutive days. After awakening, on the second and third day, they were asked whether they could recall the previous night’s dreams and whether these were pleasant or unpleasant. Female subjects followed this procedure twice: firstly, during the luteal phase and, secondly, during the follicular phase of the menstrual cycle. Subjects with higher evening or higher morning cortisol levels tended to show increased dream recall; a non-statistically significant association between morning cortisol levels and positive dream affect was also found. This association acquired statistical significance for salivary morning cortisol levels exceeding the upper normal level of 19.1 nmol/L (OR: 4.444, 95% CI: 1.108–17.830, p-value: 0.039). No connection between menstrual cycle stages and dream recall/affect was detected. In conclusion, cortisol may be a crucial neuromodulator, affecting dream recall and content. Therefore, its effects on sleep and dreams should be further studied.
Citation: Clocks & Sleep
PubDate: 2022-01-29
DOI: 10.3390/clockssleep4010003
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 16-22: Cross Sectional Study of the
Community Self-Reported Risk of Obstructive Sleep Apnoea (OSA) and
Awareness in Thessaly, Greece
Authors: Petros Kassas, Georgios D. Vavougios, Chrissi Hatzoglou, Konstantinos I. Gourgoulianis, Sotirios G. Zarogiannis
First page: 16
Abstract: The purpose of this study was to investigate the self-reported risk of obstructive sleep apnea syndrome (OSAS) in the municipality of Thessaly, Greece, and the level of awareness of both the disease and its diagnosis. Inhabitants of Thessaly (254 total; 84 men and 170 women) were studied by means of questionnaires via a telephone-randomized survey. This comprised: (a) the Berlin questionnaire for evaluation of OSAS risk; (b) the evaluation of daytime sleepiness by the Epworth Sleepiness Scale; and (c) demographic and anthropometric data. The percentage of participants at high risk for OSA was 26.77%, and the percentage of people who were at high risk of excessive daytime sleepiness was 10.63%. High risk for OSAS was found to be 3.94%. No significant differences were found between high- and low-risk OSAS participants associated with age, smoking and severity of smoking. Regarding the knowledge of the community about OSAS, the majority of the sample was aware of the entity (64.17%), while fewer had knowledge about the diagnosis (18.50%) and polysomnography (24.80%). The high risk of OSA prevalence and the low awareness of the diagnosis of OSA highlights the need for the development of health promotion programs aiming at increasing the disease awareness in the general population in order to address OSA more effectively.
Citation: Clocks & Sleep
PubDate: 2022-02-10
DOI: 10.3390/clockssleep4010004
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 23-36: Working around the Clock: Is a
Person’s Endogenous Circadian Timing for Optimal Neurobehavioral
Functioning Inherently Task-Dependent'
Authors: Rachael A. Muck, Amanda N. Hudson, Kimberly A. Honn, Shobhan Gaddameedhi, Hans P. A. Van Dongen
First page: 23
Abstract: Neurobehavioral task performance is modulated by the circadian and homeostatic processes of sleep/wake regulation. Biomathematical modeling of the temporal dynamics of these processes and their interaction allows for prospective prediction of performance impairment in shift-workers and provides a basis for fatigue risk management in 24/7 operations. It has been reported, however, that the impact of the circadian rhythm—and in particular its timing—is inherently task-dependent, which would have profound implications for our understanding of the temporal dynamics of neurobehavioral functioning and the accuracy of biomathematical model predictions. We investigated this issue in a laboratory study designed to unambiguously dissociate the influences of the circadian and homeostatic processes on neurobehavioral performance, as measured during a constant routine protocol preceded by three days on either a simulated night shift or a simulated day shift schedule. Neurobehavioral functions were measured every 2 h using three functionally distinct assays: a digit symbol substitution test, a psychomotor vigilance test, and the Karolinska Sleepiness Scale. After dissociating the circadian and homeostatic influences and accounting for inter-individual variability, peak circadian performance occurred in the late biological afternoon (in the “wake maintenance zone”) for all three neurobehavioral assays. Our results are incongruent with the idea of inherent task-dependent differences in the endogenous circadian impact on performance. Rather, our results suggest that neurobehavioral functions are under top-down circadian control, consistent with the way they are accounted for in extant biomathematical models.
Citation: Clocks & Sleep
PubDate: 2022-02-11
DOI: 10.3390/clockssleep4010005
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 37-51: Depriving Mice of Sleep also
Deprives of Food
Authors: Nina Đukanović, Francesco La Spada, Yann Emmenegger, Guy Niederhäuser, Frédéric Preitner, Paul Franken
First page: 37
Abstract: Both sleep-wake behavior and circadian rhythms are tightly coupled to energy metabolism and food intake. Altered feeding times in mice are known to entrain clock gene rhythms in the brain and liver, and sleep-deprived humans tend to eat more and gain weight. Previous observations in mice showing that sleep deprivation (SD) changes clock gene expression might thus relate to altered food intake, and not to the loss of sleep per se. Whether SD affects food intake in the mouse and how this might affect clock gene expression is, however, unknown. We therefore quantified (i) the cortical expression of the clock genes Per1, Per2, Dbp, and Cry1 in mice that had access to food or not during a 6 h SD, and (ii) food intake during baseline, SD, and recovery sleep. We found that food deprivation did not modify the SD-incurred clock gene changes in the cortex. Moreover, we discovered that although food intake during SD did not differ from the baseline, mice lost weight and increased food intake during subsequent recovery. We conclude that SD is associated with food deprivation and that the resulting energy deficit might contribute to the effects of SD that are commonly interpreted as a response to sleep loss.
Citation: Clocks & Sleep
PubDate: 2022-02-11
DOI: 10.3390/clockssleep4010006
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 52-65: Hormone Targets for the Treatment of
Sleep Disorders in Postmenopausal Women with Schizophrenia: A Narrative
Review
Authors: Alexandre González-Rodríguez, José Haba-Rubio, Judith Usall, Mentxu Natividad, Virginia Soria, Javier Labad, José A. Monreal
First page: 52
Abstract: While the early identification of insomnia in patients with schizophrenia is of clinical relevance, the use of specific compounds to treat insomnia has been studied less in postmenopausal women with schizophrenia. We aimed to explore the effects of melatonin, sex hormones, and raloxifene for the treatment of insomnia in these populations. Although melatonin treatment improved the quality and efficiency of the sleep of patients with schizophrenia, few studies have explored its use in postmenopausal women with schizophrenia. The estrogen and progesterone pathways are dysregulated in major psychiatric disorders, such as in schizophrenia. While, in the context of menopause, a high testosterone-to-estradiol ratio is associated with higher frequencies of depressive symptoms, the effects of estradiol and other sex hormones on sleep disorders in postmenopausal women with schizophrenia has not been sufficiently investigated. Raloxifene, a selective estrogen receptor modulator, has shown positive effects on sleep disorders in postmenopausal women. Future studies should investigate the effectiveness of hormonal compounds on insomnia in postmenopausal women with schizophrenia.
Citation: Clocks & Sleep
PubDate: 2022-02-15
DOI: 10.3390/clockssleep4010007
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 66-79: The Importance of Sleep and Circadian
Rhythms for Vaccination Success and Susceptibility to Viral Infections
Authors: Nina C. M. Schmitz, Ysbrand D. van der Werf, Heidi M. Lammers-van der Holst
First page: 66
Abstract: Sleep and circadian rhythms are closely involved in the immune system and its regulation. Here, we describe this relationship and provide recommendations regarding the influence of sleep and circadian rhythms on vaccination success. We review studies investigating how viral susceptibility is influenced by changes in immunological parameters as a consequence of sleep deprivation. Short sleep duration and poor sleep efficiency both appear to be strong factors leading to greater vulnerability. In addition, both sleep duration and the time of day of the vaccination seem to be associated with the magnitude of the antibody response after vaccination. Based on these findings, a recommendation would consist of a sleep duration of 7 h or more every night to both reduce the risk of infection and to optimize the efficacy of vaccination with respect to circadian timing. Improving sleep quality and its circadian timing can potentially play a role in preventing infection and in vaccination benefits. In conclusion, sufficient (or longer) sleep duration is important in both reducing susceptibility to infection and increasing antibody response after vaccination.
Citation: Clocks & Sleep
PubDate: 2022-02-16
DOI: 10.3390/clockssleep4010008
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 80-87: Measuring Sleep Health Disparities
with Polysomnography: A Systematic Review of Preliminary Findings
Authors: Faustin Armel Etindele Sosso
First page: 80
Abstract: Socioeconomic status (SES) has an unrecognized influence on behavioral risk factors as well as public health strategies related to sleep health disparities. In addition to that, objectively measuring SES’ influence on sleep health is challenging. A systematic review of polysomnography (PSG) studies investigating the relation between SES and sleep health disparities is worthy of interest and holds potential for future studies and recommendations. A literature search in databases was conducted following Prisma guidelines. Search strategy identified seven studies fitting within the inclusion criteria. They were all cross-sectional studies with only adults. Except for one study conducted in India, all of these studies took place in western countries. Overall emerging trends are: (1) low SES with its indicators (income, education, occupation and employment) are negatively associated with PSG parameters and (2) environmental factors (outside noise, room temperature and health worries); sex/gender and BMI were the main moderators of the relation between socioeconomic indicators and the variation of sleep recording with PSG. Socioeconomic inequalities in sleep health can be measured objectively. It will be worthy to examine the SES of participants and patients before they undergo PSG investigation. PSG studies should always collect socioeconomic data to discover important connections between SES and PSG. It will be interesting to compare PSG data of people from different SES in longitudinal studies and analyze the intensity of variations through time.
Citation: Clocks & Sleep
PubDate: 2022-02-18
DOI: 10.3390/clockssleep4010009
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 88-99: Pre-Sleep Cognitive Arousal Is
Negatively Associated with Sleep Misperception in Healthy Sleepers during
Habitual Environmental Noise Exposure: An Actigraphy Study
Authors: Rachel L. Sharman, Michael L. Perlis, Célyne H. Bastien, Nicola L. Barclay, Jason G. Ellis, Greg J. Elder
First page: 88
Abstract: Specific noises (e.g., traffic or wind turbines) can disrupt sleep and potentially cause a mismatch between subjective sleep and objective sleep (i.e., “sleep misperception”). Some individuals are likely to be more vulnerable than others to noise-related sleep disturbances, potentially as a result of increased pre-sleep cognitive arousal. The aim of the present study was to examine the relationships between pre-sleep cognitive arousal and sleep misperception. Sixteen healthy sleepers participated in this naturalistic, observational study. Three nights of sleep were measured using actigraphy, and each 15-s epoch was classified as sleep or wake. Bedside noise was recorded, and each 15-s segment was classified as containing noise or no noise and matched to actigraphy. Participants completed measures of habitual pre-sleep cognitive and somatic arousal and noise sensitivity. Pre-sleep cognitive and somatic arousal levels were negatively associated with subjective–objective total sleep time discrepancy (p < 0.01). There was an association between sleep/wake and noise presence/absence in the first and last 90 min of sleep (p < 0.001). These results indicate that higher levels of habitual pre-sleep arousal are associated with a greater degree of sleep misperception, and even in healthy sleepers, objective sleep is vulnerable to habitual bedside noise.
Citation: Clocks & Sleep
PubDate: 2022-02-24
DOI: 10.3390/clockssleep4010010
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 100-113: Obesity, Sex, Snoring and Severity
of OSA in a First Nation Community in Saskatchewan, Canada
Authors: James A. Dosman, Chandima P. Karunanayake, Mark Fenton, Vivian R. Ramsden, Jeremy Seeseequasis, Robert Skomro, Shelley Kirychuk, Donna C. Rennie, Kathleen McMullin, Brooke P. Russell, Niels Koehncke, Sylvia Abonyi, Malcolm King, Punam Pahwa
First page: 100
Abstract: Sleep disorders have been related to body weight, social conditions, and a number of comorbidities. These include high blood pressure and type 2 diabetes, both of which are prevalent in the First Nations communities. We explored relationships between obstructive sleep apnea (OSA) and risk factors including social, environmental, and individual circumstances. An interviewer-administered survey was conducted with adult participants in 2018–2019 in a First Nations community in Saskatchewan, Canada. The survey collected information on demographic variables, individual and contextual determinants of sleep health, and objective clinical measurements. The presence of OSA was defined as an apnea–hypopnea index (AHI) ≥5. Multiple ordinal logistic regression analysis was conducted to examine relationships between the severity of OSA and potential risk factors. In addition to the survey, 233 men and women participated in a Level 3 one-night home sleep test. Of those, 105 (45.1%) participants were reported to have obstructive sleep apnea (AHI ≥ 5). Mild and moderately severe OSA (AHI ≥ 5 to <30) was present in 39.9% and severe OSA (AHI ≥ 30) was identified in 5.2% of participants. Being male, being obese, and snoring loudly were significantly associated with severity of OSA. The severity of OSA in one First Nation appears relatively common and may be related to mainly individual factors such as loud snoring, obesity, and sex.
Citation: Clocks & Sleep
PubDate: 2022-02-24
DOI: 10.3390/clockssleep4010011
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 114-128: Circadian and Sleep Modulation of
Dreaming in Women with Major Depression
Authors: Angelina Birchler-Pedross, Sylvia Frey, Christian Cajochen, Sarah L. Chellappa
First page: 114
Abstract: Growing evidence indicates an association between reduced dream recall and depressive symptomatology. Here, we tested the prediction that reduced dream recall in individuals experiencing major depressive disorder (MDD) is due to alterations in circadian and sleep processes. Nine young healthy women (20–31 years) and eight young unmedicated women (20–31 years) diagnosed with MDD underwent a 40 h multiple nap protocol with ten alternating cycles of 150 min wake/75 min sleep under a stringently controlled circadian laboratory protocol. After each nap, we assessed dream recall, number of dreams and dream emotional load using the Sleep Mentation Questionnaire. Dream recall and the number of dreams did not significantly differ between groups (pFDR > 0.1). However, there was a significant difference for the dream emotional load (interaction of “Group” vs. “Time”, pFDR = 0.01). Women with MDD had a two-fold higher (negative) emotional load as compared to healthy control women, particularly after naps during the circadian night (between ~22:00 h and ~05:00 h; Tukey–Kramer test, p = 0.009). Furthermore, higher (negative) dream emotional load was associated with impaired mood levels in both groups (R2 = 0.71; p < 0.001). Our findings suggest that the circadian and sleep modulation of dreaming may remain intact in unmedicated young women experiencing MDD.
Citation: Clocks & Sleep
PubDate: 2022-02-28
DOI: 10.3390/clockssleep4010012
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 129-144: The Effects of Parental
Intervention on Sleep Patterns and Electronic Media Exposure in Young
Adolescents
Authors: Ofra Flint Bretler, Orna Tzischinsky, Kfir Asraf, Tamar Shochat
First page: 129
Abstract: Objective: This study evaluated the effectiveness of a parent-focused intervention aimed at the promotion of healthy sleep patterns and controlled exposure to electronic media (EM) in young adolescents. Participants: The sample included 70 dyads of parents (68 mothers and 2 fathers) and adolescents. Intervention and control groups each consisted of 35 young adolescents with a mean age of 10.7 (0.9) years old. Methods: Three waves of data collection included baseline, post-intervention, and 3 month follow-up. In each wave, adolescents reported habitual electronic media exposure and sleep patterns for a week and wore an actigraph for five nights. Parents in the intervention group participated in a six-session interactive workshop, while parents in the control group received equivalent written information by mail. Results: The intervention led to earlier bedtimes (p < 0.001), increased sleep efficiency (p < 0.01), increased sleep duration (p < 0.001) and reduced video games exposure (p < 0.01). Benefits were maintained at the follow-up. Conclusion: Interventions tailored for parents can create lasting positive changes in sleep patterns and EM exposure in young adolescents.
Citation: Clocks & Sleep
PubDate: 2022-03-01
DOI: 10.3390/clockssleep4010013
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 145-159: Sedative–Hypnotic Activity of
the Water Extracts of Coptidis Rhizoma in Rodents
Authors: Hye-Young Joung, Minsook Ye, Miyoung Lee, Yunki Hong, Minji Kim, Kyung Soo Kim, Insop Shim
First page: 145
Abstract: Many medicinal plants have been used in Asia for treating a variety of mental diseases, including insomnia and depression. However, their sedative–hypnotic effects and mechanisms have not been clarified yet. Accordingly, the objective of this study was to investigate the sedative–hypnotic effects of water extracts of five medicinal plants: Coptidis Rhizoma, Lycii Fructus, Angelicae sinensis Radix, Bupleuri Radix, and Polygonum multiflorum Thunberg. The binding abilities of five medicinal plant extracts to the GABAA–BZD and 5-HT2C receptors were compared. Their abilities to activate arylalkylamine N-acetyltransferase (AANAT), a melatonin synthesis enzyme, in pineal cells were also determined. Following in vitro tests, the sedative and hypnotic activities of extracts with the highest activities were determined in an animal sleep model. In the binding assay, the water extracts of Coptidis Rhizoma (WCR) showed high binding affinity to the GABAA–BZD and 5-HT2C receptors in a dose-dependent manner. Additionally, WCR increased the AANAT activity up to five times compared with the baseline level. Further animal sleep model experiments showed that WCR potentiated pentobarbital-induced sleep by prolonging the sleep time. It also decreased the sleep onset time in mice. In addition, WCR reduced wake time and increased non-rapid eye movement (NREM) sleep without EEG power density (percentages of δ, θ, and α waves) during NREM sleep in rats. WCR could effectively induce NREM sleep without altering the architectural physiologic profile of sleep. This is the first report of the sedative–hypnotic effect of Coptidis Rhizoma possibly by regulating GABAA and 5-HT2C receptors and by activating AANAT activity.
Citation: Clocks & Sleep
PubDate: 2022-03-04
DOI: 10.3390/clockssleep4010014
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 160-171: Sleep Loss, Daytime Sleepiness, and
Neurobehavioral Performance among Adolescents: A Field Study
Authors: Tzischinsky Orna, Barel Efrat
First page: 160
Abstract: The current study investigates the impact of sleep loss on neurobehavioral functioning and sleepiness in a natural setting among healthy adolescents. Fifty-nine adolescents (32 females) from grades 7 to 12 (mean age of 16.29 ± 1.86 years) participated in the study. All participants wore the actigraph for a continuous five to seven days, including school and nonschool days. Subjective sleepiness and neurobehavioral performance (using the psychomotor vigilance test and the digit symbol substitution test) were measured three times a day on two school days and one nonschool day. The results presented that sleep loss influenced subjective sleepiness reports, showing higher sleepiness scores following sleep loss than following sufficient night sleep. Neurobehavioral functioning across all measurements was also significantly worse following sleep loss. Furthermore, participants performed worse on weekday morning assessments than on assessments at other times of the day following sleep loss. These findings suggest that sleep loss in natural settings has a significant impact on neurobehavioral performance and subjective sleepiness. Our findings have essential implications for public policy on school schedules.
Citation: Clocks & Sleep
PubDate: 2022-03-07
DOI: 10.3390/clockssleep4010015
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 172-184: The Relationship between Acceptance
and Sleep–Wake Quality before, during, and after the First Italian
COVID-19 Lockdown
Authors: Marco Fabbri, Luca Simione, Monica Martoni, Marco Mirolli
First page: 172
Abstract: Several studies have reported that the COVID-19 pandemic has had deleterious effects on sleep quality and mood, but the mechanisms underlying these effects are not clearly understood. Recently, it has been shown that the acceptance component of mindfulness reduces anxiety, and, in turn, lower anxiety improves sleep quality. The purpose of this cross-sectional study was to assess changes in mindfulness traits, sleep–wake quality, and general distress, before, during, and after the first COVID-19 wave, testing the model in which acceptance influences sleep through anxiety in each period. A total of 250 participants were recruited before (Pre-Lockdown group: 69 participants, 29 females, 33.04 ± 12.94 years), during (Lockdown group: 78 participants, 59 females, 29.174 ± 8.50 years), and after (After-Lockdown group: 103 participants, 86 females, 30.29 ± 9.46 years) the first Italian lockdown. In each group, self-report questionnaires, assessing mindfulness facets, distress, and sleep–wake quality, were administered and assessed. The Lockdown group reported lower acceptance and higher depression, while the After-Lockdown group reported lower sleep–wake quality and higher anxiety. The results of the path analysis confirmed that higher acceptance reduced anxiety and higher anxiety decreased sleep–wake quality in all groups. Our results confirm that acceptance influences sleep through the mediating role of anxiety.
Citation: Clocks & Sleep
PubDate: 2022-03-07
DOI: 10.3390/clockssleep4010016
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 185-201: Physical Interaction between
Cyclin-Dependent Kinase 5 (CDK5) and Clock Factors Affects the Circadian
Rhythmicity in Peripheral Oscillators
Authors: Jürgen A. Ripperger, Rohit Chavan, Urs Albrecht, Andrea Brenna
First page: 185
Abstract: Circadian rhythms are self-sustained oscillators with a period of 24 h that is based on the output of transcriptional and post-translational feedback loops. Phosphorylation is considered one of the most important post-translational modifications affecting rhythmicity from cyanobacteria to mammals. For example, the lack of cyclin-dependent kinase 5 (CDK5) shortened the period length of the circadian oscillator in the Suprachiasmatic Nuclei (SCN) of mice via the destabilization of the PERIOD 2 (PER2) protein. Here, we show that CDK5 kinase activity and its interaction with clock components, including PER2 and CLOCK, varied over time in mouse embryonic fibroblast cells. Furthermore, the deletion of Cdk5 from cells resulted in a prolonged period and shifted the transcription of clock-controlled genes by about 2 to 4 h with a simple delay of chromatin binding of ARNTL (BMAL1) CLOCK. Taken together, our data indicate that CDK5 is critically involved in regulating the circadian clock in vitro at the molecular level.
Citation: Clocks & Sleep
PubDate: 2022-03-09
DOI: 10.3390/clockssleep4010017
Issue No: Vol. 4, No. 1 (2022)
- Clocks & Sleep, Vol. 4, Pages 202-207: Sleep Deprivation Does Not
Influence Photic Resetting of Circadian Activity Rhythms in Drosophila
Authors: David C. Negelspach, Sevag Kaladchibachi, Hannah K. Dollish, Fabian-Xosé Fernandez
First page: 202
Abstract: Previous investigations in humans and rodent animal models have assessed the interplay of sleep in the circadian system’s phase responses to nighttime light exposure. The resulting data have been mixed, but generally support a modulatory role for sleep in circadian photic resetting (not an absolute requirement). Drosophila have been historically used to provide important insights in the sleep and circadian sciences. However, no experiments to date have evaluated how immediate sleep need or recent sleep history affects their pacemaker’s phase readjustments to light. We did so in the current study by (1) forcing separate groups of animals to stay awake for 1 or 4 h after they were shown a broadspectrum pulse (15 min during the first half of the night, 950 lux), or (2) placing them on a restricted sleep schedule for a week before light presentation without any subsequent sleep disruption. Forced sleep restriction, whether acute or chronic, did not alter the size of light-induced phase shifts. These data are consistent with observations made in other diurnal animals and raise the possibility, more broadly, that phototherapies applied during sleep—such as may be necessary during the winter months—may still be efficacious in individuals experiencing sleep-continuity problems such as insomnia.
Citation: Clocks & Sleep
PubDate: 2022-03-21
DOI: 10.3390/clockssleep4010018
Issue No: Vol. 4, No. 1 (2022)
