Authors:Jaime K. Devine, Jake Choynowski, Caio R. Garcia, Audrey S. Simoes, Marina R. Guelere, Bruno de Godoy, Diego S. Silva, Philipe Pacheco, Steven R. Hursh First page: 515 Abstract: Fatigue risk to the pilot has been a deterrent for conducting direct flights longer than 12 h under normal conditions, but such flights were a necessity during the COVID-19 pandemic. Twenty (N = 20) pilots flying across five humanitarian missions between Brazil and China wore a sleep-tracking device (the Zulu watch), which has been validated for the estimation of sleep timing (sleep onset and offset), duration, efficiency, and sleep score (wake, interrupted, light, or deep Sleep) throughout the mission period. Pilots also reported sleep timing, duration, and subjective quality of their in-flight rest periods using a sleep diary. To our knowledge, this is the first report of commercial pilot sleep behavior during ultra-long-range operations under COVID-19 pandemic conditions. Moreover, these analyses provide an estimate of sleep score during in-flight sleep, which has not been reported previously in the literature. Citation: Clocks & Sleep PubDate: 2021-09-23 DOI: 10.3390/clockssleep3040036 Issue No:Vol. 3, No. 4 (2021)
Authors:Michele Lastella, Dean J. Miller, Manuella Quilelli, Spencer Roberts, Brad Aisbett, Dominique Condo First page: 528 Abstract: The primary aims of the present study were to examine the impact of chronotype on sleep/wake behaviour, perceived exertion, and training load among professional footballers. Thirty-six elite female professional football player’s (mean ± SD: age, 25 ± 4 y; weight, 68 ± 7 kg) sleep and training behaviours were examined for 10 consecutive nights during a pre-season period using a self-report online player-management system and wrist activity monitors. All athletes completed the Morningness-Eveningness Questionnaire (rMEQ) on the first day of data collection. Eleven participants were morning types, seventeen participants were intermediate types, and three participants were evening types. Separate linear mixed models were conducted to assess differences in sleep, perceived exertion, and training behaviours between chronotype groups. Morning types woke up earlier (wake time: 07:19 ± 01:16 vs. 07:53 ± 01:01, p = 0.04) and reported higher ratings of perceived exertion compared to intermediate types (6.7 ± 1.1 vs. 5.9 ± 1.2, p = 0.01). No differences were observed between chronotype groups for bedtime, time in bed, total sleep time, sleep efficiency, training duration, or training load. In circumstances where professional female football players are required to train at a time opposing their natural circadian preference (e.g., morning type training in the evening), their perceived exertion during training may be higher than that of players that are training at a time that aligns with their natural circadian preference (e.g., evening type training in the evening). It is important for practitioners to monitor individual trends in training variables (e.g., rating of perceived exertion, training load) with relation to athlete chronotype and training time. Future research should examine the relationship between chronotype, training time, and rating of perceived exertion across different training durations. Citation: Clocks & Sleep PubDate: 2021-10-11 DOI: 10.3390/clockssleep3040037 Issue No:Vol. 3, No. 4 (2021)
Authors:Luciana F. R. Nogueira, Pollyanna Pellegrino, José Cipolla-Neto, Claudia R. C. Moreno, Elaine C. Marqueze First page: 536 Abstract: Night workers tend to eat irregularly, both in terms of meal times and composition. The disruption in energy metabolism caused by inappropriate eating habits can negatively affect the sleep quality of these individuals. The objectives of this study were to determine the interval between the last meal and bedtime and its relationship with both diurnal and nocturnal sleep parameters, as well as to evaluate the association of the adequacy of this meal with sleep parameters. The analyses were carried out for a usual sleep routine on a workday and a day off. This cross-sectional study was part of a controlled, randomized, double-blind, crossover clinical trial. The sample comprised 30 female nursing professionals who worked permanent night shifts of 12 × 36 h. Timing and composition of the last meal were obtained from food diaries, and sleep parameters were collected via actigraphy. On multiple linear regression analysis, every hour decrease in the interval between the last meal and sleep onset there was an increase of 0.39 h on diurnal sleep duration. Regarding food intake, every 1 g of fat and 1 g of carbohydrate consumed was associated with an increase in diurnal sleep onset latency of 0.13 h and 0.02 h, respectively. These findings suggest that both timing and composition of the last meal before bedtime may be potential key factors for good diurnal and nocturnal sleep among night-shift workers. Citation: Clocks & Sleep PubDate: 2021-10-14 DOI: 10.3390/clockssleep3040038 Issue No:Vol. 3, No. 4 (2021)
Authors:Viktor Čulić, Thomas Kantermann First page: 547 Abstract: Available evidence on the risk of acute myocardial infarction (AMI) in the days after the spring daylight saving time (DST) transition suggests either a modest increase or no risk increase. Partial sleep deprivation and enhanced circadian clock misalignment have been implicated as the underlying mechanisms for increased AMI risk, probably via enhanced thrombo-inflammatory processes and activation of the sympathetic nervous system. Most of the studies, as we suggest as a perspective here, have used potentially inappropriate control periods, including the two post-transitional weeks, because adjustment after the spring DST transition lasts at least four weeks for all chronotypes and probably even beyond this period for late chronotypes. The most plausible conclusions, at the moment, for the risk of AMI after the spring DST transition are: (1) the risk is increased, (2) a relatively modest risk increase could be currently underestimated or in some studies undetected, (3) late chronotypes and/or individuals with high levels of social jetlag (a proxy for circadian clock misalignment) could be more affected by the phenomenon, and (4) underlying pathophysiological mechanisms should be further explored. As a significant part of world’s population continues to be affected by the biannual clock change, the question of increased AMI risk in the post-transitional period remains an intriguing public health issue. Citation: Clocks & Sleep PubDate: 2021-10-25 DOI: 10.3390/clockssleep3040039 Issue No:Vol. 3, No. 4 (2021)
Authors:Sarah R. Schmid, Christopher Höhn, Kathrin Bothe, Christina P. Plamberger, Monika Angerer, Belinda Pletzer, Kerstin Hoedlmoser First page: 558 Abstract: Previously, we presented our preliminary results (N = 14) investigating the effects of short-wavelength light from a smartphone during the evening on sleep and circadian rhythms (Höhn et al., 2021). Here, we now demonstrate our full sample (N = 33 men), where polysomnography and body temperature were recorded during three experimental nights and subjects read for 90 min on a smartphone with or without a filter or from a book. Cortisol, melatonin and affectivity were assessed before and after sleep. These results confirm our earlier findings, indicating reduced slow-wave-sleep and -activity in the first night quarter after reading on the smartphone without a filter. The same was true for the cortisol-awakening-response. Although subjective sleepiness was not affected, the evening melatonin increase was attenuated in both smartphone conditions. Accordingly, the distal-proximal skin temperature gradient increased less after short-wavelength light exposure than after reading a book. Interestingly, we could unravel within this full dataset that higher positive affectivity in the evening predicted better subjective but not objective sleep quality. Our results show disruptive consequences of short-wavelength light for sleep and circadian rhythmicity with a partially attenuating effect of blue-light filters. Furthermore, affective states influence subjective sleep quality and should be considered, whenever investigating sleep and circadian rhythms. Citation: Clocks & Sleep PubDate: 2021-10-28 DOI: 10.3390/clockssleep3040040 Issue No:Vol. 3, No. 4 (2021)
Authors:Tianxiang Gao, Jiayi Li, Yuji Watanabe, Chijung Hung, Akihiro Yamanaka, Kazumasa Horie, Masashi Yanagisawa, Masahiro Ohsawa, Kazuhiko Kume First page: 581 Abstract: Sleep-stage classification is essential for sleep research. Various automatic judgment programs, including deep learning algorithms using artificial intelligence (AI), have been developed, but have limitations with regard to data format compatibility, human interpretability, cost, and technical requirements. We developed a novel program called GI-SleepNet, generative adversarial network (GAN)-assisted image-based sleep staging for mice that is accurate, versatile, compact, and easy to use. In this program, electroencephalogram and electromyography data are first visualized as images, and then classified into three stages (wake, NREM, and REM) by a supervised image learning algorithm. To increase its accuracy, we adopted GAN and artificially generated fake REM sleep data to equalize the number of stages. This resulted in improved accuracy, and as little as one mouse’s data yielded significant accuracy. Due to its image-based nature, the program is easy to apply to data of different formats, different species of animals, and even outside sleep research. Image data can be easily understood; thus, confirmation by experts is easily obtained, even when there are prediction anomalies. As deep learning in image processing is one of the leading fields in AI, numerous algorithms are also available. Citation: Clocks & Sleep PubDate: 2021-11-01 DOI: 10.3390/clockssleep3040041 Issue No:Vol. 3, No. 4 (2021)
Authors:Hui-Hsien Lin, Stephanie R. Taylor, Michelle E. Farkas First page: 598 Abstract: Circadian rhythm disruption can elicit the development of various diseases, including breast cancer. While studies have used cell lines to study correlations between altered circadian rhythms and cancer, these models have different genetic backgrounds and do not mirror the changes that occur with disease development. Isogenic cell models can recapitulate changes across cancer progression. Hence, in this study, a patient-derived breast cancer model, the 21T series, was used to evaluate changes to circadian oscillations of core clock protein transcription as cells progress from normal to malignant states. Three cell lines were used: H16N2 (normal breast epithelium), 21PT (atypical ductal hyperplasia), and 21MT-1 (invasive metastatic carcinoma). The cancerous cells are both HER2+. We assessed the transcriptional profiles of two core clock proteins, BMAL1 and PER2, which represent a positive and negative component of the molecular oscillator. In the normal H16N2 cells, both genes possessed rhythmic mRNA oscillations with close to standard periods and phases. However, in the cancerous cells, consistent changes were observed: both genes had periods that deviated farther from normal and did not have an anti-phase relationship. In the future, mechanistic studies should be undertaken to determine the oncogenic changes responsible for the circadian alterations found. Citation: Clocks & Sleep PubDate: 2021-11-12 DOI: 10.3390/clockssleep3040042 Issue No:Vol. 3, No. 4 (2021)
Authors:Michael Schredl First page: 609 Abstract: Many dream content analytic studies focus on dream characters, animals, social interactions and so on, but they rarely analyze the frequency of everyday objects in dreams. In the present paper, the frequency and phenomenology of clock dreams in a dream series of 12,476 dreams of a single male dreamer was analyzed. The clock dreams (0.74% of all dreams) show a variety of contexts not only related to the time management of the dreamer within the dream. Interestingly, clocks that belong to the dreamer in waking life occurred very rarely in his dreams. Given that keeping time schedules and appointments in waking life is of importance to almost everyone, the low frequency of clock dreams might be explained by novelty, that is, waking-life experiences that repeat themselves regularly do not show up in dreams that often. Thus, studying everyday objects such as clocks in dreams might help refine the current models describing the continuity between waking and dreaming. Citation: Clocks & Sleep PubDate: 2021-11-24 DOI: 10.3390/clockssleep3040043 Issue No:Vol. 3, No. 4 (2021)
Authors:Michael Pengelly, Nathan Elsworthy, Joshua Guy, Aaron Scanlan, Michele Lastella First page: 615 Abstract: Sport-specific skills display diurnal variation across various team sports such as badminton and tennis serving accuracy and soccer dribbling, volleying, and chipping execution. However, the effects of athlete chronotype on in-game sport-specific skill performance according to time of day across team sports is not well understood. Therefore, the aim of this study was to identify the effect of player chronotype on in-game basketball performance during evening games. Professional male basketball players (n = 11) completed a morningness–eveningness questionnaire and were categorized according to chronotype (morning-type: n = 4; neither-type: n = 6; evening-type: n = 1). Box score data from the 2019/20 season were utilized to determine individual in-game performance during evening games played after 18:00 h. Composite metrics (i.e., effective field goal percentage, offensive rating, defensive rating, and player efficiency) were used as indicators of player performance. Non-significant (p ≥ 0.21) differences were evident between M-types and N-types for most performance measures. Small to very large effects were observed in the number of rebounds favoring M-types, and three-point shots attempted and made, assists, and steals favored N-types. In-game performance appeared to not be affected by chronotype (i.e., M-type vs. N-type) in evening games among professional male basketball players. The lack of observed effect between chronotype and in-game performance suggest coaching staff may not need to consider player chronotype when developing a match strategy or assigning player roles if largely dealing with M-types and N-types. However, to ensure the greatest specificity, coaching staff may endeavor to schedule habitual training times in line with that of competition in an effort to align player circadian rhythms to games. Citation: Clocks & Sleep PubDate: 2021-11-29 DOI: 10.3390/clockssleep3040044 Issue No:Vol. 3, No. 4 (2021)
Authors:Viacheslav V. Krylov First page: 624 Abstract: The influence of magnetic fields and natural geomagnetic storms on biological circadian rhythms are actively studied. This study reveals an impact of local natural perturbations in the geomagnetic field that occurred at different times of the day on circadian patterns of locomotor activity of zebrafish. A decrease in zebrafish swimming speed was observed during the geomagnetic disturbances before or after the fluctuations of diurnal geomagnetic variation. However, if the geomagnetic perturbations coincided with the fluctuations of diurnal geomagnetic variation, the decrease in zebrafish swimming speed was insignificant. This result suggests that the biological effects of geomagnetic disturbances may depend on synchronization with the diurnal geomagnetic variation. It implies that the previously published correlations between geomagnetic activity and medical or biological parameters could result from a disruption in circadian biorhythms. Citation: Clocks & Sleep PubDate: 2021-11-29 DOI: 10.3390/clockssleep3040045 Issue No:Vol. 3, No. 4 (2021)
Authors:Chorong Han, Marvin Wirianto, Eunju Kim, Mark J. Burish, Seung-Hee Yoo, Zheng Chen First page: 351 Abstract: Dysregulated circadian functions contribute to various diseases, including cardiovascular disease. Much progress has been made on chronotherapeutic applications of drugs against cardiovascular disease (CVD); however, the direct effects of various medications on the circadian system are not well characterized. We previously conducted high-throughput chemical screening for clock modulators and identified an off-patent anti-arrhythmic drug, moricizine, as a clock-period lengthening compound. In Per2:LucSV reporter fibroblast cells, we showed that under both dexamethasone and forskolin synchronization, moricizine was able to increase the circadian period length, with greater effects seen with the former. Titration studies revealed a dose-dependent effect of moricizine to lengthen the period. In contrast, flecainide, another Class I anti-arrhythmic, showed no effects on circadian reporter rhythms. Real-time qPCR analysis in fibroblast cells treated with moricizine revealed significant circadian time- and/or treatment-dependent expression changes in core clock genes, consistent with the above period-lengthening effects. Several clock-controlled cardiac channel genes also displayed altered expression patterns. Using tissue explant culture, we showed that moricizine was able to significantly prolong the period length of circadian reporter rhythms in atrial ex vivo cultures. Using wild-type C57BL/6J mice, moricizine treatment was found to promote sleep, alter circadian gene expression in the heart, and show a slight trend of increasing free-running periods. Together, these observations demonstrate novel clock-modulating activities of moricizine, particularly the period-lengthening effects on cellular oscillators, which may have clinical relevance against heart diseases. Citation: Clocks & Sleep PubDate: 2021-06-22 DOI: 10.3390/clockssleep3030022 Issue No:Vol. 3, No. 3 (2021)
Authors:Lorenzo Tonetti, Federico Camilli, Sara Giovagnoli, Vincenzo Natale, Alessandra Lugaresi First page: 366 Abstract: Early multiple sclerosis (MS) predictive markers of disease activity/prognosis have been proposed but are not universally accepted. Aim of this pilot prospective study is to verify whether a peculiar hyperactivity, observed at baseline (T0) in early relapsing-remitting (RR) MS patients, could represent a further prognostic marker. Here we report results collected at T0 and at a 24-month follow-up (T1). Eighteen RRMS patients (11 females, median Expanded Disability Status Scale-EDSS score 1.25, range EDSS score 0–2) were monitored at T0 (mean age 32.33 ± 7.51) and T1 (median EDSS score 1.5, range EDSS score 0–2.5). Patients were grouped into two groups: responders (R, 14 patients) and non-responders (NR, 4 patients) to treatment at T1. Each patient wore an actigraph for one week to record the 24-h motor activity pattern. At T0, NR presented significantly lower motor activity than R between around 9:00 and 13:00. At T1, NR were characterized by significantly lower motor activity than R between around 12:00 and 17:00. Overall, these data suggest that through the 24-h motor activity pattern, we can fairly segregate at T0 patients who will show a therapeutic failure, possibly related to a more active disease, at T1. These patients are characterized by a reduced morning level of motor activation. Further studies on larger populations are needed to confirm these preliminary findings. Citation: Clocks & Sleep PubDate: 2021-06-28 DOI: 10.3390/clockssleep3030023 Issue No:Vol. 3, No. 3 (2021)
Authors:Andrew M. Reiter, Charli Sargent, Gregory D. Roach First page: 377 Abstract: The study’s aim was to examine the effect of chronotype on cognitive performance during a single night shift. Data were collected from 72 (36f) young, healthy adults in a laboratory study. Participants had a 9 h sleep period (03:00–12:00) followed by an 8 h night shift (23:00–07:00). During the night shift, participants completed five test sessions, which included measures of subjective sleepiness, subjective alertness, and sustained attention (i.e., psychomotor vigilance task; PVT). Dim light melatonin onset (DLMO) was derived from saliva samples taken during the evening preceding the night shift. A tertile split of DLMO was used to determine three chronotype categories: earlier (DLMO = 20:22 ± 0:42), intermediate (DLMO = 21:31 ± 0:13), and later (DLMO = 22:54 ± 0:54). There were (a) significant main effects of test session (all p < 0.001); (b) no main effects of chronotype; and (c) no interaction effects between chronotype and test session on sleepiness, alertness, PVT response time, and PVT lapses. The results indicate that under controlled sleeping conditions, chronotype based on dim light melatonin onset did not affect nighttime performance. Differences in performance during night shift between chronotypes reported by field studies may be related to differences in the amount and/or timing of sleep before or between night shifts, rather than circadian timing. Citation: Clocks & Sleep PubDate: 2021-07-01 DOI: 10.3390/clockssleep3030024 Issue No:Vol. 3, No. 3 (2021)
Authors:Ritwick Agrawal, Nadim J. Ajami, Sonal Malhotra, Liang Chen, Donna L. White, Amir Sharafkhaneh, Kristi L. Hoffman, David Y. Graham, Hashem B. El-Serag, Joseph F. Petrosino, Li Jiao First page: 387 Abstract: We examined the association between the colonic adherent microbiota and nocturnal sleep duration in humans. In a cross-sectional study, 63 polyp-free adults underwent a colonoscopy and donated 206 mucosal biopsies. The gut microbiota was profiled using the 16S rRNA gene sequencing targeting the V4 region. The sequence reads were processed using UPARSE and DADA2, respectively. Lifestyle factors, including sleep habits, were obtained using an interviewer-administered questionnaire. We categorized the participants into short sleepers (<6 h per night; n = 16) and normal sleepers (6–8 h per night; n = 47) based on self-reported data. Differences in bacterial biodiversity and the taxonomic relative abundance were compared between short vs. normal sleepers, followed by multivariable analysis. A false discovery rate-adjusted p value (q value) < 0.05 indicated statistical significance. The bacterial community composition differed in short and normal sleepers. The relative abundance of Sutterella was significantly lower (0.38% vs. 1.25%) and that of Pseudomonas was significantly higher (0.14% vs. 0.08%) in short sleepers than in normal sleepers (q values < 0.01). The difference was confirmed in the multivariable analysis. Nocturnal sleep duration was associated with the bacterial community composition and structure in the colonic gut microbiota in adults. Citation: Clocks & Sleep PubDate: 2021-07-01 DOI: 10.3390/clockssleep3030025 Issue No:Vol. 3, No. 3 (2021)
Authors:Abhishek S. Prayag, Mirjam Münch, Daniel Aeschbach, Sarah L. Chellappa, Claude Gronfier First page: 398 Abstract: We thank Bracke and colleagues [...] Citation: Clocks & Sleep PubDate: 2021-07-05 DOI: 10.3390/clockssleep3030026 Issue No:Vol. 3, No. 3 (2021)
Authors:Athanasios Tselebis, Emmanouil Zoumakis, Ioannis Ilias First page: 403 Abstract: In this concise review, we present an overview of research on dream recall/affect and of the hypothalamic–pituitary–adrenal (HPA) axis, discussing caveats regarding the action of hormones of the HPA axis (mainly cortisol and its free form, cortisol-binding globulin and glucocorticoid receptors). We present results of studies regarding dream recall/affect and the HPA axis under physiological (such as waking) or pathological conditions (such as in Cushing’s syndrome or stressful situations). Finally, we try to integrate the effect of the current COVID-19 situation with dream recall/affect vis-à-vis the HPA axis. Citation: Clocks & Sleep PubDate: 2021-07-22 DOI: 10.3390/clockssleep3030027 Issue No:Vol. 3, No. 3 (2021)
Authors:Shinichi Esaki, Meiho Nakayama, Sachie Arima, Shintaro Sato First page: 409 Abstract: Previous studies of animal behavioural sleep is mainly divided into two study types, observation by video recording or counts by sensor, both of which require a complex environment and procedure. An actigraph unit is a commercially available product which can provide non-invasive monitoring human rest/activity cycles. The goal of this study was to evaluate whether actigraphy can be applied for analysing behavioural sleep in rats, since no reports have described utilization of the actigraphy unit for monitoring sleep of small animals. The actigraph unit was held on the chest of eight male rats by a loose elastic belt. The rats spent two days in a normal condition, followed by two days of sleep deprivation. Total counts measured by the actigraph could be clearly divided into two phases, sleep phase and awake phase, when the rats were kept in the normal cage. Next, the rats were moved into the sleep-deviation cage, and the total counts were significantly higher during daytime, indicating the successful induction of sleep deprivation. These results showed that the actigraphy unit monitored rest/activity cycles of rats, which will contribute to making sleep behaviour experiments easier. Citation: Clocks & Sleep PubDate: 2021-08-02 DOI: 10.3390/clockssleep3030028 Issue No:Vol. 3, No. 3 (2021)
Authors:Chandima P. Karunanayake, Vivian R. Ramsden, Clifford Bird, Jeremy Seeseequasis, Kathleen McMullin, Mark Fenton, Robert Skomro, Shelley Kirychuk, Donna C. Rennie, Brooke P. Russell, Niels Koehncke, Thomas Smith-Windsor, Malcolm King, Sylvia Abonyi, James A. Dosman, Punam Pahwa First page: 415 Abstract: Sleep is crucial for maintaining the recovery and restoration of the body and brain. Less sleep is associated with poor mental and physical performance. Seasonal changes in sleep patterns can be observed. This paper examines seasonal effects on sleep timing, duration, and problems in two Cree First Nation communities in Saskatchewan, Canada. Data were available from a community survey of 588 adults aged 18 years and older (range: 18–78 years) with 44.2% males and 55.8% females. Results are presented using descriptive statistics and a binary logistic-regression model to identify the association between seasonal changes in sleep patterns, and demographic, social, and environmental factors. The participants reported sleeping the least during the spring and summer months and sleeping the most during the fall and winter months. This was further confirmed by sleep hours and the lower proportion of recommended hours of sleep during the spring and summer, and a higher proportion of longer sleep duration during the fall and winter months. There was no significant variation in sleeping onset and wake-up times by season. Overall, there were no significant differences in the prevalence of sleep deprivation, insomnia, and excessive daytime sleepiness by season. When stratified by age group and sex, some differences existed in the prevalence of sleep problems by season. More than two-thirds (68.6%) of the participants reported that there was a change in sleep patterns across seasons, and about 26.0% reported a very or extremely marked change in sleep patterns across seasons. Changes in sleep patterns by season were related to money left at the end of the month and damage caused by dampness in the house. Citation: Clocks & Sleep PubDate: 2021-08-11 DOI: 10.3390/clockssleep3030029 Issue No:Vol. 3, No. 3 (2021)
Authors:Ilya A. Solovev, Mikhail V. Shaposhnikov, Alexey A. Moskalev First page: 429 Abstract: Chronobiotics are a group of drugs, which are utilized to modify circadian rhythms targeting clock-associated molecular mechanisms. The circadian clock is known as a controller of numerous processes in connection with aging. Hypothesis: KL001 and KS15 targeting CRY, affect lifespan, locomotor activity and circadian rhythm of Drosophila melanogaster. We observed a slight (2%, p < 0.001) geroprotective effect on median lifespan (5 µM solution of KL001 in 0.1% DMSO) and a 14% increase in maximum lifespan in the same group. KS15 10 µM solution extended males’ median lifespan by 8% (p < 0.05). The statistically significant positive effects of KL001 and KS15 on lifespan were not observed in female flies. KL001 5 µM solution improved locomotor activity in young male imagoes (p < 0.05), elevated morning activity peak in aged imagoes and modified robustness of their circadian rhythms, leaving the period intact. KS15 10 µM solution decreased the locomotor activity in constant darkness and minimized the number of rhythmic flies. KL001 5 µM solution improved by 9% the mean starvation resistance in male flies (p < 0.01), while median resistance was elevated by 50% (p < 0.0001). This phenomenon may suggest the presence of the mechanism associated with improvement of fat body glucose depos’ utilization in starvation conditions which is activated by dCRY binding KL001. Citation: Clocks & Sleep PubDate: 2021-08-20 DOI: 10.3390/clockssleep3030030 Issue No:Vol. 3, No. 3 (2021)
Authors:Christiana Harous, Gregory D. Roach, Thomas G. Kontou, Ashley J. Montero, Nicole Stuart, Charli Sargent First page: 442 Abstract: Sleep loss causes mood disturbance in non-clinical populations under severe conditions, i.e., two days/nights of sleep deprivation or a week of sleep restriction with 4–5 h in bed each night. However, the effects of more-common types of sleep loss on mood disturbance are not yet known. Therefore, the aim of this study was to examine mood disturbance in healthy adults over a week with nightly time in bed controlled at 5, 6, 7, 8 or 9 h. Participants (n = 115) spent nine nights in the laboratory and were given either 5, 6, 7, 8 or 9 h in bed over seven consecutive nights. Mood was assessed daily using the Profile of Mood States (POMS-2). Mixed-linear effects models examined the effect of time in bed on total mood disturbance and subscales of anger-hostility, confusion-bewilderment, depression-dejection, fatigue-inertia, tension-anxiety, vigour-activity and friendliness. There was no effect of time in bed on total mood disturbance (F(4, 110.42) = 1.31, p = 0.271) or any of the subscales except fatigue-inertia. Fatigue-inertia was higher in the 5 h compared with the 9 h time in bed condition (p = 0.012, d = 0.75). Consecutive nights of moderate sleep loss (i.e., 5–7 h) does not affect mood but does increase fatigue in healthy males. Citation: Clocks & Sleep PubDate: 2021-08-20 DOI: 10.3390/clockssleep3030031 Issue No:Vol. 3, No. 3 (2021)
Authors:Eirin Kolberg, Ståle Pallesen, Gunnhild Johnsen Hjetland, Inger Hilde Nordhus, Elisabeth Flo-Groeneboom First page: 449 Abstract: Bright light treatment is an effective way to influence circadian rhythms in healthy adults, but previous research with dementia patients has yielded mixed results. The present study presents a primary outcome of the DEM.LIGHT trial, a 24-week randomized controlled trial conducted at nursing homes in Bergen, Norway, investigating the effects of a bright light intervention. The intervention consisted of ceiling-mounted LED panels providing varying illuminance and correlated color temperature throughout the day, with a peak of 1000 lx, 6000 K between 10 a.m. and 3 p.m. Activity was recorded using actigraphs at baseline and after 8, 16, and 24 weeks. Non-parametric indicators and extended cosine models were used to investigate rest–activity rhythms, and outcomes were analyzed with multi-level regression models. Sixty-one patients with severe dementia (median MMSE = 4) were included. After 16 weeks, the acrophase was advanced from baseline in the intervention group compared to the control group (B = −1.02, 95%; CI = −2.00, −0.05). There was no significant difference between the groups on any other rest–activity measures. When comparing parametric and non-parametric indicators of rest–activity rhythms, 25 out of 35 comparisons were significantly correlated. The present results indicate that ambient bright light treatment did not improve rest–activity rhythms for people with dementia. Citation: Clocks & Sleep PubDate: 2021-09-13 DOI: 10.3390/clockssleep3030032 Issue No:Vol. 3, No. 3 (2021)
Authors:Rabya Mughal, Siu Sing Wong, Dagmara Dimitriou, Elizabeth Halstead First page: 465 Abstract: Children with Foetal Alcohol Spectrum Disorders (FASD) and Autism Spectrum Disorders (ASD) experience significantly higher rates of sleep disturbances than their typically developing (TD) peers. Pre-sleep anxiety and waking emotional content is known to affect the content and frequency of nightmares, which can be distressing to children and caregivers. This is the first study to analyse nightmare frequency and content in FASD, and to assess its association with psychometric outcomes. Using online caregiver questionnaires, we assessed reports from 277 caregivers of children with ASD (n = 61), FASD (n = 112), and TD children (n = 104) using the Children’s Sleep Habits Questionnaire (CSHQ), the Child Behaviour Checklist (CBCL), the Spence Children’s Anxiety Scale (SCAS), and the Behaviour Rating Inventory for Executive Functioning (BRIEF). Within the ASD group, 40.3% of caregivers reported their children had nightmares. Within the FASD group, 73.62% of caregivers reported their children had nightmares, and within the TD group, 21.36% of caregivers reported their children had nightmares. Correlation analysis revealed significant associations between anxiety and nightmares, maladaptive behaviour and nightmares, and executive functioning and nightmares in the TD and FASD groups, but not ASD group. This paper adds to the emerging body of work supporting the need for sleep interventions as part of clinical practice with regard to children with ASD and FASD. As a relatively niche but important area of study, this warrants much needed further research. Citation: Clocks & Sleep PubDate: 2021-09-16 DOI: 10.3390/clockssleep3030033 Issue No:Vol. 3, No. 3 (2021)
Authors:Janelle Chong, James Frederick Cheeseman, Matthew D. M. Pawley, Andrea Kwakowsky, Guy R. Warman First page: 482 Abstract: General anaesthesia (GA) is known to affect the circadian clock. However, the mechanisms that underlie GA-induced shifting of the clock are less well understood. Activation of γ-aminobutyric acid (GABA)-type A receptors (GABAAR) in the suprachiasmatic nucleus (SCN) can phase shift the clock and thus GABA and its receptors represent a putative pathway via which GA exerts its effect on the clock. Here, we investigated the concurrent effects of the inhalational anaesthetic, isoflurane, and light, on mouse behavioural locomotor rhythms and on α1, β3, and γ2 GABAAR subunit expression in the SCN of the mouse brain. Behavioural phase shifts elicited by exposure of mice to four hours of GA (2% isoflurane) and light (400 lux) (n = 60) were determined by recording running wheel activity rhythms in constant conditions (DD). Full phase response curves for the effects of GA + light on behavioural rhythms show that phase shifts persist in anaesthetized mice exposed to light. Daily variation was detected in all three GABAAR subunits in LD 12:12. The γ2 subunit expression was significantly increased following GA in DD (compared to light alone) at times of large behavioural phase delays. We conclude that the phase shifting effect of light on the mouse clock is not blocked by GA administration, and that γ2 may potentially be involved in the phase shifting effect of GA on the clock. Further analysis of GABAAR subunit expression in the SCN will be necessary to confirm its role. Citation: Clocks & Sleep PubDate: 2021-09-17 DOI: 10.3390/clockssleep3030034 Issue No:Vol. 3, No. 3 (2021)
Authors:Valentina Elce, Giacomo Handjaras, Giulio Bernardi First page: 495 Abstract: The study of dreams represents a crucial intersection between philosophical, psychological, neuroscientific, and clinical interests. Importantly, one of the main sources of insight into dreaming activity are the (oral or written) reports provided by dreamers upon awakening from their sleep. Classically, two main types of information are commonly extracted from dream reports: structural and semantic, content-related information. Extracted structural information is typically limited to the simple count of words or sentences in a report. Instead, content analysis usually relies on quantitative scores assigned by two or more (blind) human operators through the use of predefined coding systems. Within this review, we will show that methods borrowed from the field of linguistic analysis, such as graph analysis, dictionary-based content analysis, and distributional semantics approaches, could be used to complement and, in many cases, replace classical measures and scales for the quantitative structural and semantic assessment of dream reports. Importantly, these methods allow the direct (operator-independent) extraction of quantitative information from language data, hence enabling a fully objective and reproducible analysis of conscious experiences occurring during human sleep. Most importantly, these approaches can be partially or fully automatized and may thus be easily applied to the analysis of large datasets. Citation: Clocks & Sleep PubDate: 2021-09-19 DOI: 10.3390/clockssleep3030035 Issue No:Vol. 3, No. 3 (2021)
Authors:Jorge Mendoza First page: 236 Abstract: Natural sunlight permits organisms to synchronize their physiology to the external world. However, in current times, natural sunlight has been replaced by artificial light in both day and nighttime. While in the daytime, indoor artificial light is of lower intensity than natural sunlight, leading to a weak entrainment signal for our internal biological clock, at night the exposure to artificial light perturbs the body clock and sleep. Although electric light at night allows us “to live in darkness”, our current lifestyle facilitates nighttime exposure to light by the use, or abuse, of electronic devices (e.g., smartphones). The chronic exposure to light at nighttime has been correlated to mood alterations, metabolic dysfunctions, and poor cognition. To decipher the brain mechanisms underlying these alterations, fundamental research has been conducted using animal models, principally of nocturnal nature (e.g., mice). Nevertheless, because of the diurnal nature of human physiology, it is also important to find and propose diurnal animal models for the study of the light effects in circadian biology. The present review provides an overview of the effects of light at nighttime on physiology and behavior in diurnal mammals, including humans. Knowing how the brain reacts to artificial light exposure, using diurnal rodent models, is fundamental for the development of new strategies in human health based in circadian biology. Citation: Clocks & Sleep PubDate: 2021-04-01 DOI: 10.3390/clockssleep3020014 Issue No:Vol. 3, No. 2 (2021)
Authors:Christian Benedict, Luiz Eduardo Mateus Brandão, Ilona Merikanto, Markku Partinen, Bjørn Bjorvatn, Jonathan Cedernaes First page: 251 Abstract: The COVID-19 pandemic and related restrictions, such as stay-at-home-orders, have significantly altered daily routines and lifestyles. Given their importance for metabolic health, we herein compared sleep and meal timing parameters during vs. before the COVID-19 pandemic based on subjective recall, in an anonymous Swedish survey. Among 191 adults (mean age: 47 years; 77.5% females), we show that social jetlag, i.e., the mismatch in sleep midpoint between work and free days, was reduced by about 17 min during the pandemic compared with the pre-pandemic state (p < 0.001). Concomitantly, respondents’ sleep midpoint was shifted toward morning hours during workdays (p < 0.001). A later daily eating midpoint accompanied the shift in sleep timing (p = 0.001). This effect was mainly driven by a later scheduled first meal (p < 0.001). No difference in the timing of the day’s last meal was found (p = 0.814). Although our survey was limited in terms of sample size and by being cross-sectional, our results suggest that the delay in sleep timing due to the COVID-19 pandemic was accompanied by a corresponding shift in the timing of early but not late meals. Citation: Clocks & Sleep PubDate: 2021-04-22 DOI: 10.3390/clockssleep3020015 Issue No:Vol. 3, No. 2 (2021)
Authors:Ludivine Des Champs de Boishebert, Pierre Pradat, Hélène Bastuji, François Ricordeau, Frédéric Gormand, Pierre Le Cam, Emeric Stauffer, Thierry Petitjean, Laure Peter-Derex First page: 259 Abstract: The interpretation of the Maintenance Wakefulness Test (MWT) relies on sleep onset detection. However, microsleeps (MSs), i.e., brief periods of sleep intrusion during wakefulness, may occur before sleep onset. We assessed the prevalence of MSs during the MWT and their contribution to the diagnosis of residual sleepiness in patients treated for obstructive sleep apnea (OSA) or hypersomnia. The MWT of 98 patients (89 OSA, 82.6% male) were analyzed for MS scoring. Polysomnography parameters and clinical data were collected. The diagnostic value for detecting sleepiness (Epworth Sleepiness Scale > 10) of sleep onset latency (SOL) and of the first MS latency (MSL) was assessed by the area under the receiver operating characteristic (ROC) curve (AUC, 95% CI). At least one MS was observed in 62.2% of patients. MSL was positively correlated with SOL (r = 0.72, p < 0.0001) but not with subjective scales, clinical variables, or polysomnography parameters. The use of SOL or MSL did not influence the diagnostic performance of the MWT for subjective sleepiness assessment (AUC = 0.66 95% CI (0.56, 0.77) versus 0.63 95% CI (0.51, 0.74)). MSs are frequent during MWTs performed in patients treated for sleep disorders, even in the absence of subjective sleepiness, and may represent physiological markers of the wake-to-sleep transition. Citation: Clocks & Sleep PubDate: 2021-04-30 DOI: 10.3390/clockssleep3020016 Issue No:Vol. 3, No. 2 (2021)
Authors:Quyen N. T. Nguyen, Toan Le, Quyen B. T. Huynh, Arveity Setty, Toi V. Vo, Trung Q. Le First page: 274 Abstract: The rapid growth of point-of-care polysomnographic alternatives has necessitated standardized evaluation and validation frameworks. The current average across participant validation methods may overestimate the agreement between wearable sleep tracker devices and polysomnography (PSG) systems because of the high base rate of sleep during the night and the interindividual difference across the sampling population. This study proposes an evaluation framework to assess the aggregating differences of the sleep architecture features and the chronologically epoch-by-epoch mismatch of the wearable sleep tracker devices and the PSG ground truth. An AASM-based sleep stage categorizing method was proposed to standardize the sleep stages scored by different types of wearable trackers. Sleep features and sleep stage architecture were extracted from the PSG and the wearable device’s hypnograms. Therefrom, a localized quantifier index was developed to characterize the local mismatch of sleep scoring. We evaluated different commonly used wearable sleep tracking devices with the data collected from 22 different subjects over 30 nights of 8-h sleeping. The proposed localization quantifiers can characterize the chronologically localized mismatches over the sleeping time. The outperformance of the proposed method over existing evaluation methods was reported. The proposed evaluation method can be utilized for the improvement of the sensor design and scoring algorithm. Citation: Clocks & Sleep PubDate: 2021-05-03 DOI: 10.3390/clockssleep3020017 Issue No:Vol. 3, No. 2 (2021)
Authors:Michael Schredl, Lara C. Wood First page: 289 Abstract: Romantic relationships are an important part of human life and thus, according to the continuity hypothesis of dreaming, one’s romantic partner should show up in dreams quite frequently. The present study is based on 1612 dream reports provided by 425 students. The findings confirmed the hypothesis that partner dreams are more frequent than ex-partner dreams and, thus, support the continuity hypothesis of dreaming. Moreover, interactions with ex-partners within the dream were more often negatively toned compared to dreamed interactions with the partner. Unexpectedly, we also found more positive emotions and friendliness in ex-partner dreams compared to partner dreams, indicating that partner dreams are more mundane. To conclude, dreams reflect important aspects of romantic partnerships and their break-ups and, thus, can be very helpful in psychotherapy. Citation: Clocks & Sleep PubDate: 2021-05-26 DOI: 10.3390/clockssleep3020018 Issue No:Vol. 3, No. 2 (2021)
Authors:Kirsie R. Lundholm, Kimberly A. Honn, Lillian Skeiky, Rachael A. Muck, Hans P. A. Van Dongen First page: 298 Abstract: In shift work settings and on-call operations, workers may be at risk of sleep inertia when called to action immediately after awakening from sleep. However, individuals may differ substantially in their susceptibility to sleep inertia. We investigated this using data from a laboratory study in which 20 healthy young adults were each exposed to 36 h of total sleep deprivation, preceded by a baseline sleep period and followed by a recovery sleep period, on three separate occasions. In the week prior to each laboratory session and on the corresponding baseline night in the laboratory, participants either extended their sleep period to 12 h/day or restricted it to 6 h/day. During periods of wakefulness in the laboratory, starting right after scheduled awakening, participants completed neurobehavioral tests every 2 h. Testing included the Karolinska Sleepiness Scale to measure subjective sleepiness, for which the data were analyzed with nonlinear mixed-effects regression to quantify sleep inertia. This revealed considerable interindividual differences in the magnitude of sleep inertia, which were highly stable within individuals after both baseline and recovery sleep periods, regardless of study condition. Our results demonstrate that interindividual differences in subjective sleepiness due to sleep inertia are substantial and constitute a trait. Citation: Clocks & Sleep PubDate: 2021-06-03 DOI: 10.3390/clockssleep3020019 Issue No:Vol. 3, No. 2 (2021)
Authors:Maria Ballester Roig, Tanya Leduc, Cassandra Areal, Valérie Mongrain First page: 312 Abstract: Uncaria rhynchophylla is a plant highly used in the traditional Chinese and Japanese medicines. It has numerous health benefits, which are often attributed to its alkaloid components. Recent studies in humans show that drugs containing Uncaria ameliorate sleep quality and increase sleep time, both in physiological and pathological conditions. Rhynchophylline (Rhy) is one of the principal alkaloids in Uncaria species. Although treatment with Rhy alone has not been tested in humans, observations in rodents show that Rhy increases sleep time. However, the mechanisms by which Rhy could modulate sleep have not been comprehensively described. In this review, we are highlighting cellular pathways that are shown to be targeted by Rhy and which are also known for their implications in the regulation of wakefulness and sleep. We conclude that Rhy can impact sleep through mechanisms involving ion channels, N-methyl-d-aspartate (NMDA) receptors, tyrosine kinase receptors, extracellular signal-regulated kinases (ERK)/mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K)/RAC serine/threonine-protein kinase (AKT), and nuclear factor-kappa B (NF-κB) pathways. In modulating multiple cellular responses, Rhy impacts neuronal communication in a way that could have substantial effects on sleep phenotypes. Thus, understanding the mechanisms of action of Rhy will have implications for sleep pharmacology. Citation: Clocks & Sleep PubDate: 2021-06-09 DOI: 10.3390/clockssleep3020020 Issue No:Vol. 3, No. 2 (2021)
Authors:Andrew M. Reiter, Charli Sargent, Gregory D. Roach First page: 342 Abstract: Chronotype reflects circadian timing and can be determined from biological markers (e.g., dim light melatonin onset; DLMO), or questionnaires (e.g., Morningness-Eveningness Questionnaire; MEQ, or Munich Chronotype Questionnaire; MCTQ). The study’s aim was to quantify concordance between chronotype categorisations based on these measures. A total of 72 (36f) young, healthy adults completed the MEQ and MCTQ and provided saliva samples hourly in dim light during the evening in a laboratory. The corrected midpoint of sleep on free days (MSFsc) was derived from MCTQ, and tertile splits were used to define early, intermediate and late DLMO-CT, MEQ-CT and MSFsc-CT chronotype categories. DLMO correlated with MEQ score (r = −0.25, p = 0.035) and MSFsc (r = 0.32, p = 0.015). For early, intermediate and late DLMO-CT categories, mean(SD) DLMO were 20:25(0:46), 21:33(0:10) and 23:03(0:53). For early, intermediate and late MEQ-CT categories, mean(SD) MEQ scores were 60.5(5.3), 51.4(2.9) and 40.8 (5.0). For early, intermediate and late MSFsc-CT categories, mean(SD) MSFsc were 03:23(0:34), 04:37(0:12) and 05:55(0:48). Low concordance of categorisations between DLMO-CT and MEQ-CT (37%), and between DLMO-CT and MSFsc-CT (37%), suggests chronotype categorisations depend on the measure used. To enable valid comparisons with previous results and reduce the likelihood of misleading conclusions, researchers should select measures and statistical techniques appropriate to the construct of interest and research question. Citation: Clocks & Sleep PubDate: 2021-06-17 DOI: 10.3390/clockssleep3020021 Issue No:Vol. 3, No. 2 (2021)
Authors:Jessica Rosano, Tiffani Howell, Russell Conduit, Pauleen Bennett First page: 1 Abstract: Pet–owner co-sleeping is increasingly common in some parts of the world. Adult owners often subjectively report benefits of co-sleeping with pets, although objective actigraphy reports conversely indicate sleep disruptions due to the pet. Because limited research is available regarding pet–owner co-sleeping in non-adult samples, the aim of this two-part study was to explore whether co-sleeping improves sleep quality in adolescents, an age group in which poor sleep patterns are well documented. In Study One, an online survey with 265 pet-owning 13-to-17-year-old participants found that over 78% co-slept with their pet. Average sleep quality scores for co-sleepers and non-co-sleepers indicated generally poor sleep, with no differences in sleep quality depending on age, gender, or co-sleeping status. Study Two consisted of two preliminary case studies, using actigraphy on dog–adolescent co-sleepers. In both cases, high sleep concordance was observed, but owners again experienced generally poor sleep quality. Future actigraphy research is needed, including larger sample sizes and a control group of non-co-sleepers, to validate the preliminary findings from this study, but our limited evidence suggests that co-sleeping with a pet may not impact sleep quality in adolescents. Citation: Clocks & Sleep PubDate: 2021-01-04 DOI: 10.3390/clockssleep3010001 Issue No:Vol. 3, No. 1 (2021)
Authors:Chen Du, Megan Chong Hueh Zan, Min Jung Cho, Jenifer I. Fenton, Pao Ying Hsiao, Richard Hsiao, Laura Keaver, Chang-Chi Lai, HeeSoon Lee, Mary-Jon Ludy, Wan Shen, Winnie Chee Siew Swee, Jyothi Thrivikraman, Kuo-Wei Tseng, Wei-Chin Tseng, Juman Almotwa, Clare E. Feldpausch, Sara Yi Ling Folk, Suzannah Gadd, Linyutong Wang, Wenyan Wang, Xinyi Zhang, Robin M. Tucker First page: 12 Abstract: Health behaviors of higher education students can be negatively influenced by stressful events. The global COVID-19 pandemic presents a unique opportunity to characterize and compare health behaviors across multiple countries and to examine how these behaviors are shaped by the pandemic experience. Undergraduate and graduate students enrolled in universities in China, Ireland, Malaysia, South Korea, Taiwan, the Netherlands and the United States (USA) were recruited into this cross-sectional study. Eligible students filled out an online survey comprised of validated tools for assessing sleep quality and duration, dietary risk, alcohol misuse and physical activity between late April and the end of May 2020. Health behaviors were fairly consistent across countries, and all countries reported poor sleep quality. However, during the survey period, the COVID-19 pandemic influenced the health behaviors of students in European countries and the USA more negatively than Asian countries, which could be attributed to the differences in pandemic time course and caseloads. Students who experienced a decline in sleep quality during the COVID-19 pandemic had higher dietary risk scores than students who did not experience a change in sleep quality (p = 0.001). Improved sleep quality was associated with less sitting time (p = 0.010). Addressing sleep issues among higher education students is a pressing concern, especially during stressful events. These results support the importance of making education and behavior-based sleep programming available for higher education students in order to benefit students’ overall health. Citation: Clocks & Sleep PubDate: 2021-01-15 DOI: 10.3390/clockssleep3010002 Issue No:Vol. 3, No. 1 (2021)
Authors:Cathalijn H.C. Leenaars, Stevie Van der Mierden, Ruud N.J.M.A. Joosten, Marnix A. Van der Weide, Mischa Schirris, Maurice Dematteis, Franck L.B. Meijboom, Matthijs G.P. Feenstra, André Bleich First page: 31 Abstract: Animals, including humans, frequently make decisions involving risk or uncertainty. Different strategies in these decisions can be advantageous depending the circumstances. Short sleep duration seems to be associated with more risky decisions in humans. Animal models for risk-based decision making can increase mechanistic understanding, but very little data is available concerning the effects of sleep. We combined primary- and meta-research to explore the relationship between sleep and risk-based decision making in animals. Our first objective was to create an overview of the available animal models for risky decision making. We performed a systematic scoping review. Our searches in Pubmed and Psychinfo retrieved 712 references, of which 235 were included. Animal models for risk-based decision making have been described for rodents, non-human primates, birds, pigs and honey-bees. We discuss task designs and model validity. Our second objective was to apply this knowledge and perform a pilot study on the effect of sleep deprivation. We trained and tested male Wistar rats on a probability discounting task; a “safe” lever always resulted in 1 reward, a “risky” lever resulted in 4 or no rewards. Rats adapted their preferences to variations in reward probabilities (p < 0.001), but 12 h of sleep deprivation during the light phase did not clearly alter risk preference (p = 0.21). Citation: Clocks & Sleep PubDate: 2021-01-20 DOI: 10.3390/clockssleep3010003 Issue No:Vol. 3, No. 1 (2021)
Authors:Greta Mainieri, Giuseppe Loddo, Federica Provini First page: 53 Abstract: Non-rapid eye movement (NREM) sleep parasomnias are characterized by motor and emotional behaviors emerging from incomplete arousals from NREM sleep and they are currently referred to as disorders of arousal (DoA). Three main clinical entities are recognized, namely confusional arousal, sleep terror and sleepwalking. DoA are largely present in pediatric populations, an age in which they are considered as transitory, unhabitual physiological events. The literature background in the last twenty years has extensively shown that DoA can persist in adulthood in predisposed individuals or even appear de novo in some cases. Even though some episodes may arise from stage 2 of sleep, most DoA occur during slow wave sleep (SWS), and particularly during the first two sleep cycles. The reasons for this timing are linked to the intrinsic structure of SWS and with the possible influence on this sleep phase of predisposing, priming and precipitating factors for DoA episodes. The objective of this paper is to review the intrinsic sleep-related features and chronobiological aspects affecting SWS, responsible for the occurrence of the majority of DoA episodes during the first part of the night. Citation: Clocks & Sleep PubDate: 2021-01-21 DOI: 10.3390/clockssleep3010004 Issue No:Vol. 3, No. 1 (2021)
Authors:Christopher Höhn, Sarah R. Schmid, Christina P. Plamberger, Kathrin Bothe, Monika Angerer, Georg Gruber, Belinda Pletzer, Kerstin Hoedlmoser First page: 66 Abstract: Smartphone usage strongly increased in the last decade, especially before bedtime. There is growing evidence that short-wavelength light affects hormonal secretion, thermoregulation, sleep and alertness. Whether blue light filters can attenuate these negative effects is still not clear. Therefore, here, we present preliminary data of 14 male participants (21.93 ± 2.17 years), who spent three nights in the sleep laboratory, reading 90 min either on a smartphone (1) with or (2) without a blue light filter, or (3) on printed material before bedtime. Subjective sleepiness was decreased during reading on a smartphone, but no effects were present on evening objective alertness in a GO/NOGO task. Cortisol was elevated in the morning after reading on the smartphone without a filter, which resulted in a reduced cortisol awakening response. Evening melatonin and nightly vasodilation (i.e., distal-proximal skin temperature gradient) were increased after reading on printed material. Early slow wave sleep/activity and objective alertness in the morning were only reduced after reading without a filter. These results indicate that short-wavelength light affects not only circadian rhythm and evening sleepiness but causes further effects on sleep physiology and alertness in the morning. Using a blue light filter in the evening partially reduces these negative effects. Citation: Clocks & Sleep PubDate: 2021-01-22 DOI: 10.3390/clockssleep3010005 Issue No:Vol. 3, No. 1 (2021)
Authors:Nicola M. Ludin, Alma Orts-Sebastian, James F. Cheeseman, Janelle Chong, Alan F. Merry, David Cumin, Shin Yamazaki, Matthew D. M. Pawley, Guy R. Warman First page: 87 Abstract: Following general anaesthesia (GA), patients frequently experience sleep disruption and fatigue, which has been hypothesized to result at least in part by GA affecting the circadian clock. Here, we provide the first comprehensive time-dependent analysis of the effects of the commonly administered inhalational anaesthetic, isoflurane, on the murine circadian clock, by analysing its effects on (a) behavioural locomotor rhythms and (b) PER2::LUC expression in the suprachiasmatic nuclei (SCN) of the mouse brain. Behavioural phase shifts elicited by exposure of mice (n = 80) to six hours of GA (2% isoflurane) were determined by recording wheel-running rhythms in constant conditions (DD). Phase shifts in PER2::LUC expression were determined by recording bioluminescence in organotypic SCN slices (n = 38) prior to and following GA exposure (2% isoflurane). Full phase response curves for the effects of GA on behaviour and PER2::LUC rhythms were constructed, which show that the effects of GA are highly time-dependent. Shifts in SCN PER2 expression were much larger than those of behaviour (c. 0.7 h behaviour vs. 7.5 h PER2::LUC). We discuss the implications of this work for understanding how GA affects the clock, and how it may inform the development of chronotherapeutic strategies to reduce GA-induced phase-shifting in patients. Citation: Clocks & Sleep PubDate: 2021-01-26 DOI: 10.3390/clockssleep3010006 Issue No:Vol. 3, No. 1 (2021)
Authors:James A Dosman, Chandima P Karunanayake, Mark Fenton, Vivian R Ramsden, Robert Skomro, Shelley Kirychuk, Donna C Rennie, Jeremy Seeseequasis, Clifford Bird, Kathleen McMullin, Brooke P Russell, Niels Koehncke, Thomas Smith-Windsor, Malcolm King, Sylvia Abonyi, Punam Pahwa First page: 98 Abstract: Insomnia is a common problem in Canada and has been associated with increased use of health care services and economic burden. This paper examines the prevalence and risk factors for insomnia in two Cree First Nation communities in Saskatchewan, Canada. Five hundred and eighty-eight adults participated in a baseline survey conducted as part of the First Nations Sleep Health Collaborative Project. The prevalence of insomnia was 19.2% among participants with an Insomnia Severity Index score of ≥15. Following the definition of nighttime insomnia symptoms, however, the prevalence of insomnia was much higher, at 32.6%. Multivariate logistic regression modeling revealed that age, physical health, depression diagnosis, chronic pain, prescription medication use for any health condition, and waking up during the night due to terrifying dreams, nightmares, or flashbacks related to traumatic events were risk factors for insomnia among participants from two Saskatchewan Cree First Nation communities. Citation: Clocks & Sleep PubDate: 2021-01-28 DOI: 10.3390/clockssleep3010007 Issue No:Vol. 3, No. 1 (2021)
Authors:Anne E. Aulsebrook, Robin D. Johnsson, John A. Lesku First page: 115 Abstract: Sleep has a multitude of benefits and is generally considered necessary for optimal performance. Disruption of sleep by extended photoperiods, moonlight and artificial light could therefore impair performance in humans and non-human animals alike. Here, we review the evidence for effects of light on sleep and subsequent performance in birds. There is accumulating evidence that exposure to natural and artificial sources of light regulates and suppresses sleep in diurnal birds. Sleep also benefits avian cognitive performance, including during early development. Nevertheless, multiple studies suggest that light can prolong wakefulness in birds without impairing performance. Although there is still limited research on this topic, these results raise intriguing questions about the adaptive value of sleep. Further research into the links between light, sleep and performance, including the underlying mechanisms and consequences for fitness, could shed new light on sleep evolution and urban ecology. Citation: Clocks & Sleep PubDate: 2021-01-28 DOI: 10.3390/clockssleep3010008 Issue No:Vol. 3, No. 1 (2021)
Authors:Meagan E Crowther, Sally A Ferguson, Grace E Vincent, Amy C Reynolds First page: 132 Abstract: Shift work is associated with adverse chronic health outcomes. Addressing chronic disease risk factors including biomedical risk factors, behavioural risk factors, as well as sleep and perceived health status, affords an opportunity to improve health outcomes in shift workers. The present study aimed to conduct a systematic review, qualitative synthesis, and meta-analysis of non-pharmacological interventions targeting chronic disease risk factors, including sleep, in shift workers. A total of 8465 records were retrieved; 65 publications were eligible for inclusion in qualitative analysis. Random-effects meta-analysis were conducted for eight eligible health outcomes, including a total of thirty-nine studies. Interventions resulted in increased objective sleep duration (Hedges’ g = 0.73; CI: 0.36, 1.10, k = 16), improved objective sleep efficiency (Hedges’ g = 0.48; CI: 0.20, 0.76, k = 10) and a small increase in both subjective sleep duration (Hedges’ g = 0.11; CI: −0.04, 0.27, k = 19) and sleep quality (Hedges’ g = 0.11; CI: −0.11, 0.33, k = 21). Interventions also improved perceived health status (Hedges’ g = 0.20; CI: −0.05, 0.46, k = 8), decreased systolic (Hedges’ g = 0.26; CI: −0.54, 0.02, k = 7) and diastolic (Hedges’ g = 0.06; CI: −0.23, 0.36, k = 7) blood pressure, and reduced body mass index (Hedges’ g = −0.04; CI: −0.37, 0.29, k = 9). The current study suggests interventions may improve chronic disease risk factors and sleep in shift workers; however, this could only be objectively assessed for a limited number of risk factor endpoints. Future interventions could explore the impact of non-pharmacological interventions on a broader range of chronic disease risk factors to better characterise targets for improved health outcomes in shift workers. Citation: Clocks & Sleep PubDate: 2021-01-28 DOI: 10.3390/clockssleep3010009 Issue No:Vol. 3, No. 1 (2021)
Authors:Clocks &amp; Sleep Editorial Office Clocks &amp; Sleep Editorial Office First page: 179 Abstract: The peer review process represents the driving force of journal development, with reviewers acting as the gatekeepers who ensure that Clocks & Sleep maintains its high-quality standard of published papers [...] Citation: Clocks & Sleep PubDate: 2021-02-01 DOI: 10.3390/clockssleep3010010 Issue No:Vol. 3, No. 1 (2021)
Authors:Peter Bracke, Eowyn Van de Putte, Wouter R. Ryckaert First page: 181 Abstract: Dose-response curves for circadian phase shift and melatonin suppression in relation to white or monochromatic nighttime illumination can be scaled to melanopic weighed illumination for normally constricted pupils, which makes them easier to interpret and compare. This is helpful for a practical applications. Citation: Clocks & Sleep PubDate: 2021-02-10 DOI: 10.3390/clockssleep3010011 Issue No:Vol. 3, No. 1 (2021)
Authors:Rachel Van Drunen, Kristin Eckel-Mahan First page: 189 Abstract: The nearly ubiquitous expression of endogenous 24 h oscillations known as circadian rhythms regulate the timing of physiological functions in the body. These intrinsic rhythms are sensitive to external cues, known as zeitgebers, which entrain the internal biological processes to the daily environmental changes in light, temperature, and food availability. Light directly entrains the master clock, the suprachiasmatic nucleus (SCN) which lies in the hypothalamus of the brain and is responsible for synchronizing internal rhythms. However, recent evidence underscores the importance of other hypothalamic nuclei in regulating several essential rhythmic biological functions. These extra-SCN hypothalamic nuclei also express circadian rhythms, suggesting distinct regions that oscillate either semi-autonomously or independent of SCN innervation. Concurrently, the extra-SCN hypothalamic nuclei are also sensitized to fluctuations in nutrient and hormonal signals. Thus, food intake acts as another powerful entrainer for the hypothalamic oscillators’ mediation of energy homeostasis. Ablation studies and genetic mouse models with perturbed extra-SCN hypothalamic nuclei function reveal their critical downstream involvement in an array of functions including metabolism, thermogenesis, food consumption, thirst, mood and sleep. Large epidemiological studies of individuals whose internal circadian cycle is chronically disrupted reveal that disruption of our internal clock is associated with an increased risk of obesity and several neurological diseases and disorders. In this review, we discuss the profound role of the extra-SCN hypothalamic nuclei in rhythmically regulating and coordinating body wide functions. Citation: Clocks & Sleep PubDate: 2021-02-25 DOI: 10.3390/clockssleep3010012 Issue No:Vol. 3, No. 1 (2021)
Authors:Rodrigo Torres-Castro, Luis Vasconcello-Castillo, Homero Puppo, Ignacio Cabrera-Aguilera, Matías Otto-Yáñez, Javiera Rosales-Fuentes, Jordi Vilaró First page: 227 Abstract: Obstructive sleep apnoea (OSA) constitutes a public health problem, with various systemic consequences that can increase cardiovascular morbidity and mortality as well as increase healthcare expenditure. This review discusses the rationale and effects of using general physical exercise, oropharyngeal exercises, and respiratory muscle training as an adjunctive treatment for patients with sleep apnoea. The recommended treatment for OSA is the use of continuous positive airway pressure, which is a therapy that prevents apnoea events by keeping the airways open. In the last decade, coadjuvant treatments that aim to support weight loss (including diet and physical exercise) and oropharyngeal exercises have been proposed to lower the apnoea/hypopnoea index among patients with OSA. Based on the available evidence, health professionals could decide to incorporate these therapeutic strategies to manage patients with sleep apnoea. Citation: Clocks & Sleep PubDate: 2021-03-03 DOI: 10.3390/clockssleep3010013 Issue No:Vol. 3, No. 1 (2021)
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