Hyperarousal features in the sleep architecture of individuals with and without insomnia.

Sleep architecture encodes relevant information on the structure of sleep and has been used to assess hyperarousal in insomnia. This study investigated whether polysomnography-derived sleep architecture displays signs of hyperarousal in individuals with insomnia compared with individuals without insomnia. Data from Phase 3 clinical trials, private clinics and a cohort study were analysed. A comprehensive set of sleep architecture features previously associated with hyperarousal were retrospectively analysed focusing on sleep-wake transition probabilities, electroencephalographic spectra and sleep spindles, and enriched with a novel machine learning algorithm called the Wake Electroencephalographic Similarity Index. This analysis included 1710 individuals with insomnia and 1455 individuals without insomnia. Results indicate that individuals with insomnia had a higher likelihood of waking from all sleep stages, and showed increased relative alpha during Wake and N1 sleep and increased theta power during Wake when compared with individuals without insomnia. Relative delta power was decreased and Wake Electroencephalographic Similarity Index scores were elevated across all sleep stages except N3, suggesting more wake-like activity during these stages in individuals with insomnia. Additionally, sleep spindle density was decreased, and spindle dispersion was increased in individuals with insomnia. These findings suggest that insomnia is characterized by a dysfunction in sleep quality with a continuous hyperarousal, evidenced by changes in sleep-wake architecture.

The first-night effect and the consistency of short sleep in insomnia disorder.

The nature and degree of objective sleep impairments in insomnia disorder remain unclear. This issue is complicated further by potential changes in sleep architecture on the first compared with subsequent nights in the laboratory. Evidence regarding differential first-night effects in people with insomnia disorder and controls is mixed. Here, we aimed to further characterize insomnia- and night-related differences in sleep architecture. A comprehensive set of 26 sleep variables was derived from two consecutive nights of polysomnography in 61 age-matched patients with insomnia and 61 good sleeper controls. People with insomnia expressed consistently poorer sleep than controls on several variables during both nights. While poorer sleep during the first night was observed in both groups, there were qualitative differences regarding the specific sleep variables expressing a first-night effect. Short sleep (total sleep time < 6 hr) was more likely during the first night and in insomnia, although approximately 40% of patients with insomnia presenting with short sleep on night 1 no longer met this criterion on night 2, which is important given the notion of short-sleeping insomnia as a robust subtype.

Increased training load promotes sleep propensity and slow-wave sleep in endurance runners: Can a high-heat-capacity mattress topper modulate this effect?

The present study aimed to: (1) investigate sleep architecture in response to an overload training and taper periods among endurance runners; and (2) assess the sleep benefits of a high-heat-capacity mattress topper. Twenty-one trained male endurance runners performed a 2-week usual training regimen (baseline) followed by 2-week overload and taper periods. From overload to the end of the taper period, they were assigned into two groups based on the mattress topper used: high-heat-capacity mattress topper (n = 11) or low-heat-capacity mattress topper (n = 10). Training load was assessed daily using the session rating of perceived exertion. Following each period, sleep was monitored by polysomnography, and nocturnal core body temperature was recorded throughout the night. Irrespective of the group, awakening episodes > 5 min decreased following overload compared with baseline (-0.48, p = 0.05). Independently of mattress topper, each 100 A.U. increase in 7-day training load prior to polysomnographic recording was associated with higher slow-wave sleep proportion (ß = +0.13%; p = 0.05), lower sleep-onset latency (ß = -0.49 min; p = 0.05), and a reduction in the probability of transition from N1 sleep stage to wakefulness (ß = -0.12%; p = 0.05). Sleeping on a high-heat-capacity mattress topper did not affect any sleep variable compared with a low-heat-capacity mattress topper. Increased training loads promote slow-wave sleep and sleep propensity, highlighting the adaptative nature of sleep to diurnal activity and the role of sleep in physiological recovery. Further studies are required on the potential benefits of high-heat-capacity mattress toppers on sleep architecture among athletes.

Identifying time-resolved features of nocturnal sleep characteristics of narcolepsy using machine learning.

The differential diagnosis of narcolepsy type 1, a rare, chronic, central disorder of hypersomnolence, is challenging due to overlapping symptoms with other hypersomnolence disorders. While recent years have seen significant growth in our understanding of nocturnal polysomnography narcolepsy type 1 features, there remains a need for improving methods to differentiate narcolepsy type 1 nighttime sleep features from those of individuals without narcolepsy type 1. We aimed to develop a machine learning framework for identifying sleep features to discriminate narcolepsy type 1 from clinical controls, narcolepsy type 2 and idiopathic hypersomnia. The population included polysomnography data from 350 drug-free individuals (114 narcolepsy type 1, 90 narcolepsy type 2, 105 idiopathic hypersomnia, and 41 clinical controls) collected at the National Reference Centers for Narcolepsy in Montpelier, France. Several sets of nocturnal sleep features were explored, as well as the value of time-resolving sleep architecture by analysing sleep per quarter-night. Several patterns of nighttime sleep evolution emerged that differed between narcolepsy type 1, clinical controls, narcolepsy type 2 and idiopathic hypersomnia, with increased nighttime instability observed in patients with narcolepsy type 1. Using machine learning models, we identified rapid eye movement sleep onset as the best single polysomnography feature to distinguish narcolepsy type 1 from controls, narcolepsy type 2 and idiopathic hypersomnia. By combining multiple feature sets capturing different aspects of sleep across quarter-night periods, we were able to further improve between-group discrimination and could identify the most discriminative sleep features. Our results highlight salient polysomnography features and the relevance of assessing their time-dependent changes during sleep that could aid diagnosis and measure the impact of novel therapeutics in future clinical trials.

The Ecology of Human Sleep (EcoSleep) Cohort Study: Protocol for a longitudinal repeated measurement burst design study to assess the relationship between sleep determinants and outcomes under real-world conditions across time of year.

The interplay of daily life factors, including mood, physical activity, or light exposure, influences sleep architecture and quality. Laboratory-based studies often isolate these determinants to establish causality, thereby sacrificing ecological validity. Furthermore, little is known about time-of-year changes in sleep and circadian-related variables at high resolution, including the magnitude of individual change across time of year under real-world conditions. The Ecology of Human Sleep (EcoSleep) cohort study will investigate the combined impact of sleep determinants on individuals' daily sleep episodes to elucidate which waking events modify sleep patterns. A second goal is to describe high-resolution individual sleep and circadian-related changes across the year to understand intra- and inter-individual variability. This study is a prospective cohort study with a measurement-burst design. Healthy adults aged 18-35 years (N = 12) will be enrolled for 12 months. Participants will continuously wear actimeters and pendant-attached light loggers. A subgroup will also measure interstitial fluid glucose levels (six paticipants). Every 4 weeks, all participants will undergo three consecutive measurement days of four ecological momentary assessments each day ('bursts') to sample sleep determinants during wake. Participants will also continuously wear temperature loggers (iButtons) during the bursts. Body weight will be captured before and after the bursts in the laboratory. The bursts will be separated by two at-home electroencephalogram recordings each night. Circadian phase and amplitude will be estimated during the bursts from hair follicles, and habitual melatonin onset will be derived through saliva sampling. Environmental parameters (bedroom temperature, humidity, and air pressure) will be recorded continuously.

Variations in the sleep-related breathing disorder index on polysomnography between men with HIV and controls: a matched case-control study.

BACKGROUND: Both sleep-related breathing disorders (SRBDs) and HIV infection can interfere with normal sleep architecture, and also cause physical and psychological distress. We aimed to understand the differences in the obstructive patterns, sleep architecture, physical and psychological distress when compared between people living with HIV (PLWH) and matched the severity of SRBDs controls. METHODS: A comparative study using matched case-control design was conducted. Men with HIV infection (case group) were enrolled from 2016 to 2019. A control group with HIV seronegative men were matched for SRBDs severity, and were selected from sleep medicine center database for comparison. RESULTS: The mean age of the 108 men (including 54 cases and 54 matched controls) was 33.75 years. Central-apnea index (CI) was higher in the case group rather than matched controls (mean CI, 0.34 vs. 0.17, p = 0.049). PLWH had a lower mean percentage of stage 3 sleep (10.26% vs. 13.94%, p = 0.034) and a higher percentage of rapid eye movement sleep (20.59% vs. 17.85%, p = 0.011) compared to matched controls. Nocturnal enuresis and sleepiness causing traffic accidents were more frequent complaint in PLWH compared to controls. CONCLUSIONS: Early detected SRBDs and subtypes in PLWH to begin treatment for the underlying cause could reduce the risk of sleepiness-related traffic accidents.

Correlations between sleep architecture and sleep-related masseter muscle activity in children with sleep bruxism.

BACKGROUND: Sleep bruxism (SB) occurring during No-REM (nREM) sleep and increase in microarousals per hour have been described in adults, but not in children. OBJECTIVE: To assess the correlation between sleep architecture and masseter muscle activity related to sleep bruxism (SB/MMA) in children. MATERIALS AND METHODS: Forty-three children aged 7-12 years (mean age: 9.4 ± 1.3) with confirmed SB underwent a two-night polysomnographic (PSG) study in a sleep laboratory, for accommodation (first night) and data collection (second night). Data on sleep architecture (total sleep duration (TSD), sleep efficiency (SE), sleep onset latency (SOL), REM and nREM sleep duration and proportion and microarousals/hour during REM and nREM sleep) and episodes/hour of SB/MMA were recorded. Single and multiple-variable linear regression analyses were performed to assess the correlation between data on sleep architecture (predictors) and SB/MMA (dependent variable). RESULTS: Shorter TSD, REM and nREM stage 1 sleep duration, longer SOL and more microarousals/hour during REM and nREM sleep were found to be positive predictors of SB/MMA in children in the multiple-variable regression analysis (R2  = 0.511). CONCLUSION: Within the limitations of this study, it can be concluded that SB/MMA is correlated with altered sleep architecture in children (shorter total sleep duration (TSD), shorter nREM and REM sleep and higher microarousals during REM and nREM sleep). Nevertheless, the clinical significance of these findings need to be demonstrated in future studies.

Sleep architecture as a candidate for phenotyping sleep bruxism: A narrative physiological review.

BACKGROUND: Sleep bruxism (SB), an oral behaviour in otherwise healthy individuals, is characterised by frequent rhythmic masticatory muscle activity (RMMA) during sleep. RMMA/SB episodes occur over various sleep stages (N1-N3 and rapid eye movement (REM)), sleep cycles (non-REM to REM), and frequently with microarousals. It currently remains unclear whether these characteristics of sleep architecture are phenotype candidates for the genesis of RMMA/SB. OBJECTIVES: This narrative review investigated the relationship between sleep architecture and the occurrence of RMMA as a SB phenotype candidate. METHODS: PubMed research was performed using keywords related to RMMA/SB and sleep architecture. RESULTS: In non-SB and SB healthy individuals, RMMA episodes were most frequent in the light non-REM sleep stages N1 and N2, particularly during the ascending phase of sleep cycles. The onset of RMMA/SB episodes in healthy individuals was preceded by a physiological arousal sequence of autonomic cardiovascular to cortical activation. It was not possible to extract a consistent sleep architecture pattern in the presence of sleep comorbidities. The lack of standardisation and variability between subject complexified the search for specific sleep architecture phenotype(s). CONCLUSION: In otherwise healthy individuals, the genesis of RMMA/SB episodes is largely affected by oscillations in the sleep stage and cycle as well as the occurrence of microarousal. Furthermore, a specific sleep architecture pattern cannot be confirmed in the presence of sleep comorbidity. Further studies are needed to delineate sleep architecture phenotype candidate(s) that contribute to the more accurate diagnosis of SB and treatment approaches using standardised and innovative methodologies.

Altered sleep architecture in children and adolescents with Down syndrome.

OBJECTIVE: Children with Down syndrome (DS) may experience changes in sleep architecture (i.e., different sleep stages) that then affect waketime functioning, including learning, mood, and disruptive behavior. For designing and testing interventions, it is important to document any differences in sleep architecture in children with DS with and without co-occurring diagnoses, including neuropsychiatric diagnoses and obstructive sleep apnea (OSA). METHODS: A retrospective cohort study was performed at Massachusetts General Hospital for children and adolescents with DS who underwent polysomnography (PSG) between August 2016 and July 2022. Patient data collected from the electronic medical record included diagnoses, age at PSG, and PSG report. Statistical analysis included unpaired T tests to test hypotheses about differences in sleep architecture within age groups, and differences between children with DS and a co-occurring diagnosis. One way ANOVA was used to determine statistical significance of OSA severity within patients with DS. RESULTS: When compared by age group, those with DS had negative changes in sleep architecture (e.g., less sleep and more wake) when compared to normative data. Within this cohort, having a co-occurring diagnosis of autism resulted in further, negative effects on sleep architecture. 89% of those with DS had diagnosed OSA but only those with severe OSA experienced negative effects on sleep architecture. CONCLUSION: Age is an important covariate when studying the sleep of children with DS and neurotypical children. Studies are needed to test whether minimizing the observed differences in sleep architecture will translate to improved learning, mood, and behavioral outcomes, and how treating OSA affects sleep architecture.

Preoperative slow-wave sleep is associated with postoperative delirium after heart valve surgery: A prospective pilot study.

Postoperative delirium (POD) is a very common neurological complication after valve surgery. Some studies have shown that preoperative sleep disorder is associated with POD, but the correlation between preoperative slow wave sleep (SWS) and POD remains unclear. Therefore, this study aims to identify the correlation between preoperative slow wave sleep and postoperative delirium in patients with heart valve disease. This was a prospective, observational study of elective valve surgery patients admitted to the Heart Medical Center between November 2021 and July 2022. Polysomnography (PSG) was used to monitor sleep architecture from 9:30 p.m. for 1 night before surgery to 6:30 a.m. on the day of surgery. Patients were assessed for postoperative delirium from postoperative day 1 to extubation or day 5 by using the Richmond Agitation/Sedation Scale (RASS) and the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). A total of 60 elective valve surgery patients were enrolled in this study. Prolonged N1 (11.44%) and N2 (58.62%) sleep, decreased N3 sleep (8.75%) and REM sleep (18.24%) within normal limits were the overall sleep architecture. Compared with patients without POD, patients with POD had less slow wave sleep 1 night before surgery (5.77% vs 10.88%, p < 0.001). After adjusting for confounding factors, slow wave sleep (OR: 0.647, 95% CI 0.493-0.851, p = 0.002) was found to be a protective factor for postoperative delirium. The preoperative SWS is a predictive factor of the POD in patients undergoing valve surgery. But further studies with larger sample sizes are still needed to elucidate the relationship between preoperative slow wave sleep and postoperative delirium.

The impacts of intra-individual daily sleep variability on daytime functioning and sleep architecture in healthy young adults: An experimental study.

Sleep variability is commonly seen in the young populations. This study aimed to examine the impacts of experimentally induced sleep variability on sleepiness, mood, cognitive performance and sleep architectures among young adults. Thirty-six healthy individuals (aged 18-22 years) were randomly assigned to either variable sleep schedule (n = 20) or control (n = 16) groups. The protocol involved 1 week of regular sleep (time in bed = 7.5 hr) in the home setting, followed by one adaptation night (time in bed = 7.5 hr), one baseline night (time in bed = 7.5 hr), and 6 nights of sleep manipulation in the laboratory monitored by polysomnography (three cycles of variable sleep schedule by changing daily time in bed alternating between 6 hr and 9 hr for variable sleep schedule group versus fixed sleep schedule with daily time in bed for 7.5 hr for control group). Sleepiness, mood, sustained attention, processing speed, response inhibition and working memory were measured every morning and evening. The variable sleep schedule group reported a higher level of sleepiness, especially in the mornings, and increased negative mood in the evenings. There were no significant differences in positive mood, cognitive performance and sleep macro- and micro-structures. Our results showed the negative effects of sleep variability on daytime functioning especially sleepiness and negative mood, suggesting the need to address variable sleep schedules through sleep intervention.

Impact of ground-level ozone exposure on sleep quality and electroencephalogram patterns at different time scales.

Ozone exposure is associated with various adverse health outcomes, but its impact on sleep quality is uncertain. Here we assessed the causal effect of long-term (yearly and monthly) exposure to ozone on nocturnal workday sleep time in a national representative sample from the China Family Panel Study, using a difference-in-differences approach. We further followed ninety healthy Chinese young adults four times in four seasons from September 2020 to June 2021, measured their daily sleep architecture using accelerometers, ascertained daily ozone exposure, recorded 5-min eye-closed resting-state electroencephalogram (EEG) signals at the last day of each one-week-long measurement session, and explored the effect of ozone exposure on objectively-measured sleep architecture. In the national sample, we found that every 1 interquartile range (IQR) µg/m3 increase in yearly and monthly ozone exposure was causally associated with 7.31 (p = 0.0039) and 4.19 (p = 0.040) minutes decline in nocturnal workday sleep time; the dose-response curve represented a quasi-linear pattern with no safety threshold, and plateaued at higher concentrations. In the small-scale study with objectively-measured sleep architecture, we found that every 1 IQR µg/m3 increase in the weekly ozone exposure was associated with 5.33 min decrease in night-time total sleep time (p = 0.031), 1.63 percentage points decrease in sleep efficiency (p < 0.001), 1.99 min increase in sleep latency (p = 0.0070), and 5.34 min increase in wake after sleep onset time (p = 0.0016) in a quasi-linear pattern. Notably, we found the accumulating trend of ozone exposure on sleep quality during both the short-term and long-term periods. We also found that short-term ozone exposure was associated with altered EEG patterns, mediated by sleep quality. This study indicates that long-term and short-term ozone exposures have negative and accumulating impacts on sleep quality and might impair brain functioning. More hidden health burdens of ozone are worth exploring.

Optimizing sleep across the menopausal transition.

Women frequently experience sleep disturbances, particularly night-time awakenings, as they transition menopause and enter postmenopause. Sleep is essential for optimal functioning and health. Persistent and distressing sleep disturbances across menopause can negatively impact daytime functioning and productivity, and increase risk for mental and physical health conditions. While multiple factors can disturb sleep, two unique factors in the context of menopause are vasomotor symptoms and the changing reproductive hormone environment. Vasomotor symptoms are associated with sleep disturbances and contribute significantly to awakenings and amount of time spent awake during the night. Even after accounting for vasomotor and depressive symptoms, lower estradiol and higher follicle stimulating hormone levels, indicative of menopause, are associated with sleep disturbance, particularly awakenings, suggesting that the hormone environment may directly affect sleep. Management strategies for clinically significant menopausal sleep disturbances include cognitive behavioral therapy for insomnia, which is effective and durable in treating menopausal insomnia. Hormone therapy alleviates sleep disturbances, particularly in the presence of disruptive vasomotor symptoms. Sleep disturbances have a significant impact on women's functioning and health, and there is a need for further research of the underlying mechanisms to advance effective preventative and treatment strategies that ensure optimal health and well-being of midlife women.

Greater female than male resilience to mortality and morbidity in the Scn8a mouse model of pediatric epilepsy.

AIMS: Females and males of all ages are affected by epilepsy; however, unlike many clinical studies, most preclinical research has focused on males. Genetic variants in the voltage-gated sodium channel gene, SCN8A, are associated with a broad spectrum of neurological and epileptic syndromes. Here we investigate sex differences in the natural history of the Scn8a-N1768D knockin mouse model of pediatric epilepsy. METHODS: We utilize 24/7 video to monitor juveniles and adults of both sexes to investigate variability in seizure activity (e.g. onset and frequency), mortality and morbidity, response to cannabinoids, and mode of death. We also monitor sleep architecture using a noninvasive piezoelectric method in order to identify factors that influence seizure severity and outcome. RESULTS: Both sexes had nearly 100% penetrance in seizure onset and early mortality. However, adult heterozygous (D/+) females were more resilient as exhibited by the ability to tolerate more seizures over a longer lifespan. Homozygous (D/D) juveniles did not exhibit a sex difference in overall survival. Female estrus cycle was disrupted before seizure onset, while sleep was disrupted in both sexes in association with seizure onset. Females typically died while in convulsive status epilepticus; however, a high proportion of males died while not experiencing behavioral seizures. Only juvenile and adult males benefited from cannabinoid administration. CONCLUSIONS: These results support the hypothesis that factors associated with sexual differentiation play a role in the neurobiology of epilepsy and point to the importance of including both sexes in the design of studies to identify new epilepsy therapies.

The Potential Role of Sleep in Promoting a Healthy Body Composition: Underlying Mechanisms Determining Muscle, Fat, and Bone Mass and Their Association with Sleep.

Sleep plays an essential role in human life. While sleep is a state elicited by the brain, its vital role reaches beyond maintaining brain health. Unhealthy sleeping habits have been associated with increased risk for inflammation, obesity, or diabetes. Evidence is emerging that sleep guides processes playing an important role in promoting the regulation of endocrine function involved in tissue regeneration and tissue remodelling. Thereby, sleep presumably is a critical factor contributing to the balance of core body tissues: bone, fat, and muscle mass. Given the increasing prevalence of various chronic diseases and comorbidities due to unhealthy lifestyle choices, sleep could be a key target to promote a healthy body composition up until old age. Here, we review the potential role of sleep and its underlying brain oscillations in body core tissues turnover. Specifically, we discuss potential underlying mechanisms linking sleep to body composition, both during rest and under challenging conditions. Among other described pathways, we highlight the possible role of the growth hormone that was found to be involved in the homeostasis of all core body tissues and has been strongly linked to brain activity dominating deep sleep, the so-called slow waves. Finally, we formulate important questions to be addressed in future research on the effect of sleep on body composition and specifically emphasize the importance of intervention studies to move from correlative to causal evidence.

Progressive muscle relaxation increases slow-wave sleep during a daytime nap.

Sleep is critical for health, cognition, and restorative processes, and yet, many experience chronic sleep restriction. Sleep interventions have been designed to enhance overnight sleep quality and physiology. Components of these interventions, like relaxation-based progressive muscle relaxation (PMR), have been studied in isolation and have shown direct effects on sleep architecture, including increasing time in restorative, slow-wave sleep (SWS). These relaxation methods have been understudied in naps, which are effective fatigue countermeasures that reduce deleterious effects of chronic sleep restriction. We hypothesised that PMR should boost SWS in a nap, as compared to an active control. We used a between-subject design in which healthy young adults underwent PMR training or listened to Mozart music (control) prior to a 90-min nap opportunity. We assessed changes in the amount and lateralisation of SWS, as evidence suggests left hemispheric lateralisation may be a proxy for recuperative sleep needs, and changes to state-dependent anxiety and fatigue before and after the nap to assess intervention success. We found PMR participants spent ~10 min more in SWS, equivalent to 125% more time, than the control group, and concomitantly, significantly less time in rapid eye movement sleep. PMR participants also had greater right lateralised slow-wave activity and delta activity compared to the control suggesting a more well-rested brain profile during sleep. Further, pre-sleep anxiety levels predicted nap architecture in the intervention group, suggesting benefits may be impacted by anxiety. The feasibility and accessibility of PMR prior to a nap make this an interesting research avenue to pursue with strong translational application.

Sleep architecture of short sleep time in patients with obstructive sleep apnea: a retrospective single-facility study.

PURPOSE: Sleep architecture consists of rapid eye movement (REM) sleep and non-REM sleep time. Non-REM sleep time is further classified into three stages by depth (stage N1-N3). Some studies have reported that short sleep time predicts all-cause mortality. Short sleep time can have characteristics of sleep architecture which contribute to poor prognosis. Obstructive sleep apnea (OSA) is a disease which causes cessation or decline of ventilation during sleep due to upper airway stenosis and affects sleep architecture. Few studies have reported on the sleep architecture of short sleep time in patients with OSA. Therefore, we aimed to observe this phenomenon. METHODS: From May 2008 to September 2021, patients diagnosed with OSA at our facility were assessed for clinical history and underwent full-night polysomnography (PSG). These patients were classified into two groups: total sleep time (TST) recorded on PSG consisting of a short TST (< 7 h) group and a not short TST (≥ 7 h) group. RESULTS: Of 266 patients with OSA, compared to the not short TST group (n = 131), the short TST group (n = 135) had a lower REM sleep time (%) and a higher stage N1 sleep time (%). There was a significant difference in age between the two groups, so sub-analyses classified the patients by age: non-elderly patients (< 65 years) and elderly patients (≥ 65 years) to adjust for age. Both sub-analyses showed similar results to the analysis for the combined ages regarding sleep architecture. CONCLUSION: Patients with OSA who had short sleep time had disordered sleep architecture with a lower REM sleep time (%) and more stage N1 sleep time.

Studying the Effect of Long COVID-19 Infection on Sleep Quality Using Wearable Health Devices: Observational Study.

BACKGROUND: Patients with COVID-19 have increased sleep disturbances and decreased sleep quality during and after the infection. The current published literature focuses mainly on qualitative analyses based on surveys and subjective measurements rather than quantitative data. OBJECTIVE: In this paper, we assessed the long-term effects of COVID-19 through sleep patterns from continuous signals collected via wearable wristbands. METHODS: Patients with a history of COVID-19 were compared to a control arm of individuals who never had COVID-19. Baseline demographics were collected for each subject. Linear correlations among the mean duration of each sleep phase and the mean daily biometrics were performed. The average duration for each subject's total sleep time and sleep phases per night was calculated and compared between the 2 groups. RESULTS: This study includes 122 patients with COVID-19 and 588 controls (N=710). Total sleep time was positively correlated with respiratory rate (RR) and oxygen saturation (SpO2). Increased awake sleep phase was correlated with increased heart rate, decreased RR, heart rate variability (HRV), and SpO2. Increased light sleep time was correlated with increased RR and SpO2 in the group with COVID-19. Deep sleep duration was correlated with decreased heart rate as well as increased RR and SpO2. When comparing different sleep phases, patients with long COVID-19 had decreased light sleep (244, SD 67 vs 258, SD 67; P=.003) and decreased deep sleep time (123, SD 66 vs 128, SD 58; P=.02). CONCLUSIONS: Regardless of the demographic background and symptom levels, patients with a history of COVID-19 infection demonstrated altered sleep architecture when compared to matched controls. The sleep of patients with COVID-19 was characterized by decreased total sleep and deep sleep.

A Week of Sleep Restriction Does Not Affect Nighttime Glucose Concentration in Healthy Adult Males When Slow-Wave Sleep Is Maintained.

The aim of this laboratory-based study was to examine the effect of sleep restriction on glucose regulation during nighttime sleep. Healthy males were randomly assigned to one of two conditions: 9 h in bed (n = 23, age = 24.0 year) or 5 h in bed (n = 18, age = 21.9 year). Participants had a baseline night with 9 h in bed (23:00-08:00 h), then seven nights of 9 h (23:00-08:00 h) or 5 h (03:00-08:00 h) in bed. Participants were mostly seated during the daytime but had three bouts of treadmill walking (4 km·h-1 for 10 min) at ~14:40 h, ~17:40 h, and ~20:40 h each day. On the baseline night and night seven, glucose concentration in interstitial fluid was assessed by using continuous glucose monitors, and sleep was assessed by using polysomnography. On night seven, compared to the 9 h group, the 5 h group obtained less total sleep (292 min vs. 465 min) and less REM sleep (81 min vs. 118 min), but their slow-wave sleep did not differ (119 min vs. 120 min), and their glucose concentration during sleep did not differ (5.1 mmol·L-1 vs. 5.1 mmol·L-1). These data indicate that sleep restriction does not cause elevated levels of circulating glucose during nighttime sleep when slow-wave sleep is maintained. In the future, it will be important to determine whether increased insulin is required to maintain circulating glucose at a normal level when sleep is restricted.

When the Locus Coeruleus Speaks Up in Sleep: Recent Insights, Emerging Perspectives.

For decades, numerous seminal studies have built our understanding of the locus coeruleus (LC), the vertebrate brain's principal noradrenergic system. Containing a numerically small but broadly efferent cell population, the LC provides brain-wide noradrenergic modulation that optimizes network function in the context of attentive and flexible interaction with the sensory environment. This review turns attention to the LC's roles during sleep. We show that these roles go beyond down-scaled versions of the ones in wakefulness. Novel dynamic assessments of noradrenaline signaling and LC activity uncover a rich diversity of activity patterns that establish the LC as an integral portion of sleep regulation and function. The LC could be involved in beneficial functions for the sleeping brain, and even minute alterations in its functionality may prove quintessential in sleep disorders.