Role Of Sleep Research Articles

The role of sleep and sleep disorders in the new 2024 European Society of Cardiology guidelines.

The role of sleep and sleep disorders in the new 2024 European Society of Cardiology guidelines.

Melatonin’s role in the timing of sleep onset is conserved in nocturnal mice

Melatonin supplementation strengthens non‐restorative sleep rhythms and its temporal alignment in both humans and night-active rodents. Of note, although the sleep cycle is reversed in day-active and night-active (nocturnal) mammals, both, produce melatonin at night under the control of the circadian clock. The effects of exogenous melatonin on sleep and sleepiness are relatively clear, but its endogenous role in sleep, particularly, in timing sleep onset (SO), remains poorly understood. We show in nocturnal mice that the increases in mid-nighttime sleep episodes, and the mid-nighttime decline in activity, are coupled to nighttime melatonin signaling. Furthermore, we show that endogenous melatonin modulates SO by reducing the threshold for wake-to-sleep transitioning. Such link between melatonin and SO timing may explain phenomena such as increased sleep propensity in circadian rhythm sleep disorders and chronic insomnia in patients with severely reduced nocturnal melatonin levels. Our findings demonstrate that melatonin’s role in sleep is evolutionarily conserved, effectively challenging the argument that melatonin cannot play a major role in sleep regulation in nocturnal mammals, where the main activity phase coincides with high melatonin levels.

Role of Sleep in Depressive Disorders and the Potential Therapeutic Role of Short-Term Sleep Deprivation and Light Therapy: A Review

Role of Sleep in Depressive Disorders and the Potential Therapeutic Role of Short-Term Sleep Deprivation and Light Therapy: A Review

The role of sleep in links between daily interpersonal stress and internalizing and externalizing symptoms during middle childhood

BackgroundInterpersonal stress has been consistently linked with poorer adjustment, and healthy sleep may play a promotive or protective role in this relation. However, little is known regarding such associations among children. The current study examined longitudinal associations between daily interpersonal stress, sleep, and internalizing/externalizing symptoms during middle childhood. MethodsAt age 8 years, participants wore actigraphy watches for 7 days to capture sleep, and primary caregivers reported on children's daily interpersonal stress, internalizing/externalizing symptoms, and sleep problems. At age 9 years, children self-reported symptoms. ResultsGreater daily interpersonal stress at age 8 years predicted greater internalizing/externalizing symptoms at age 9 years. Higher sleep efficiency predicted fewer externalizing symptoms. Sleep duration moderated links between interpersonal stress and internalizing/externalizing symptoms, but associations were positive and significant for children with average and high duration only. ConclusionFindings advance our understanding of links between interpersonal stress, sleep, and child adjustment and can inform targeted family and school interventions.

Are Sleep Parameters and Chronotype Associated with Eating Disorder Risk? A Cross-Sectional Study of University Students in Spain.

Objectives: Eating disorders (EDs) have emerged as a growing public health concern. However, the role of sleep in this context remains underexplored. The aim of this cross-sectional study was to determine the associations between sleep parameters and chronotype with ED risk in a sample of university students in Spain. Methods: ED risk was assessed via the Sick, Control, One stone, Fat, Food Questionnaire, and sleep quality was assessed via the Pittsburgh Sleep Quality Index. Other sleep parameters and chronotypes were self-reported. Sociodemographic, body composition, lifestyle, and depressive symptom data were collected. Logistic and linear regression models adjusted for the main confounders were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of the study associations. Results: A total of 403 students (70.2% female) aged 18 to 30 years participated in the study. Those reporting poor sleep quality (OR = 1.85, 95% CI 1.08-3.17, p = 0.025) and ≤6 h of night-time sleep duration (OR = 4.14, 95% CI 2.00-8.57, p < 0.01) were more likely to be at risk of EDs in the adjusted analyses. The association between night-time sleep duration and the risk of ED did not remain significant when we adjusted for sleep quality. In addition, an evening chronotype was associated with an increased risk of EDs (OR = 1.68, 95% CI 1.07-2.66, p = 0.039) only before adjustment for confounders. Conclusions: Among university students, poorer sleep quality was cross-sectionally associated with EDs. Future prospective studies are needed to examine whether promoting sleep quality may serve as an effective strategy for preventing the risk of EDs.

Sex differences in the role of sleep on cognition in older adults.

The study aimed to investigate sex differences in the relationship between sleep quality (self-report and objective) and cognitive function across three domains (executive function, verbal memory, and attention) in older adults. We analyzed cross-sectional data from 207 participants with normal cognition (NC) or mild cognitive impairment (89 males and 118 females) aged over 60 years. The relationship between sleep quality and cognitive performance was estimated using generalized additive models. Objective sleep was measured with the GT9X Link ActiGraph, and self-reported sleep was measured with the Pittsburgh Sleep Quality Index. We found that females exhibited lower executive function with increased objective total sleep time, with a steeper decline in performance after 400 minutes (p = .015). Additionally, longer objective sleep correlated with lower verbal memory linearly (p = .046). In males, a positive linear relationship emerged between objective sleep efficiency and executive function (p = .036). Self-reported sleep was not associated with cognitive performance in females and males with NC. However, in males with cognitive impairment, there was a nonlinear positive relationship between self-reported sleep and executive function (p < .001). Our findings suggest that the association between sleep parameters on cognition varies between older males and females, with executive function being most strongly associated with objective sleep for both sexes top of form. Interventions targeting sleep quality to mitigate cognitive decline in older adults may need to be tailored according to sex, with distinct approaches for males and females.

Acute sleep disruption reduces fear memories in male and female mice.

Sleep problems are a prominent feature of mental health conditions including post-traumatic stress disorder (PTSD). Despite its potential importance, the role of sleep in the development of and/or recovery from trauma-related illnesses is not understood. Interestingly, there are reports that sleep disruption immediately after a traumatic experience can reduce fear memories, an effect that could be utilized therapeutically in humans. While the mechanisms of this effect are not completely understood, one possible explanation for these findings is that immediate sleep disruption interferes with consolidation of fear memories, rendering them weaker and more sensitive to intervention. Here, we allowed fear-conditioned mice to sleep immediately after fear conditioning during a time frame (18 h) that includes and extends beyond periods typically associated with memory consolidation before subjecting them to 6-h of sleep disruption. Mice exposed to this delayed regimen showed dramatic reductions in fear during tests conducted immediately after sleep disruption, as well as 24 h later. This sleep disruption regimen also increased levels of mRNA encoding brain-derived neurotrophic factor (BDNF), a molecule implicated in neuroplasticity, in the basolateral amygdala (BLA), a brain area implicated in fear and its extinction. These findings raise the possibility that the effects of our delayed sleep disruption regimen are not due to disruption of memory consolidation, but instead are caused by BDNF-mediated neuroadaptations within the BLA that actively suppress expression of fear. Treatments that safely reduce expression of fear memories would have considerable therapeutic potential in the treatment of conditions triggered by trauma.

Sleep disturbances in type 1 diabetes and mitigating cardiovascular risk.

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in persons with type 1 diabetes (T1D). Despite control of known cardiovascular (CV) risk factors and better glycemic management, persons with T1D still face heightened CVD risk, suggesting additional contributing factors. Sleep has recently been recognized as a CV risk factor, however; the role of sleep in CVD specifically in T1D population has only started to emerge. Extensive evidence suggests that persons with T1D often encounter sleep disturbances. This review aims to comprehensively explore the relationship between sleep disturbances and CVD in T1D, and proposed possible mediators including glycemic control which has been studied more extensively, and less studied factors such as blood pressure, lipid metabolism, and weight management. Stress and self-care behaviors likely also play a role in the relationship between sleep disturbances and CVD. The evidence regarding sleep interventions in the context of T1D in mitigating these CV risk factors has recently been shown in early, small-scale studies. Sleep assessments should be a part of standard of care in persons with T1D. Further research should focus on understanding the impact and mechanistic pathways of sleep disturbances on CV risk, and developing T1D specific sleep interventions to reduce CVD burden in this population.

Sleep as a contributor to socioeconomic disparities in hypertension: The Midlife in the United States (MIDUS II) Study.

Hypertension is highly prevalent and is a major risk factor for cardiovascular disease. There is a higher burden of hypertension among individuals of lower socioeconomic status (SES), yet the role of sleep in understanding socioeconomic disparities in hypertension is unclear. We investigated whether sleep quality is a partial mediator of the association between SES and hypertension. We used data from the Midlife in the United States II Study, 2004-2009 (n = 426). Analyses were conducted in 2023. Participants underwent 7-day actigraphy and clinical assessments. Sleep quality measures included actigraphy-defined wakefulness after sleep onset (WASO) and sleep efficiency. Hypertension was measured via three consecutive blood pressure readings, and SES was measured via educational attainment. Models were fit adjusting for age, gender, race, body mass index, and perceived stress. Participants had a mean age of 53.5 years (SD = 12.4) and 41.0% were African American. The prevalences of poor WASO (>30 minutes), low sleep efficiency (<85%), and hypertension were 77.7%, 67.1%, and 61.0%, respectively. Education was not associated with hypertension. However, individuals with low vs. high sleep efficiency had 24% higher prevalence of hypertension (aPR = 1.24, 95% CI: 1.02 to 1.51), higher systolic blood pressure (aβ = 4.61, 95% CI: 0.69 to 8.53), and higher diastolic blood pressure (aβ = 2.50, 95% CI: 0.10 to 4.89). Education was not significantly associated with sleep after adjustment. There was no evidence of sleep mediating the SES-hypertension relation. Effective interventions to lower hypertension prevalence should consider targeting sleep quality. Future research should explore the intersectionality of SES and race in hypertension.

Constitutive and Conditional Epitope Tagging of Endogenous G-Protein-Coupled Receptors in Drosophila.

To visualize the cellular and subcellular localization of neuromodulatory G-protein-coupled receptors in Drosophila, we implement a molecular strategy recently used to add epitope tags to ionotropic receptors at their endogenous loci. Leveraging evolutionary conservation to identify sites more likely to permit insertion of a tag, we generated constitutive and conditional tagged alleles for Drosophila 5-HT1A, 5-HT2A, 5-HT2B, Oct β 1R, Oct β 2R, two isoforms of OAMB, and mGluR The conditional alleles allow for the restricted expression of tagged receptor in specific cell types, an option not available for any previous reagents to label these proteins. We show expression patterns for these receptors in female brains and that 5-HT1A and 5-HT2B localize to the mushroom bodies (MBs) and central complex, respectively, as predicted by their roles in sleep. By contrast, the unexpected enrichment of Octβ1R in the central complex and of 5-HT1A and 5-HT2A to nerve terminals in lobular columnar cells in the visual system suggest new hypotheses about their functions at these sites. Using an additional tagged allele of the serotonin transporter, a marker of serotonergic tracts, we demonstrate diverse spatial relationships between postsynaptic 5-HT receptors and presynaptic 5-HT neurons, consistent with the importance of both synaptic and volume transmission. Finally, we use the conditional allele of 5-HT1A to show that it localizes to distinct sites within the MBs as both a postsynaptic receptor in Kenyon cells and a presynaptic autoreceptor.

The Complex Relationship between Sleep and Cognitive Reserve: A Narrative Review Based on Human Studies.

Sleep and brain/cognitive/neural reserve significantly impact well-being and cognition throughout life. This review aims to explore the intricate relationship between such factors, with reference to their effects on human cognitive functions. The specific goal is to understand the bidirectional influence that sleep and reserve exert on each other. Up to 6 February 2024, a methodical search of the literature was conducted using the PubMed database with terms related to brain, cognitive or neural reserve, and healthy or disturbed sleep. Based on the inclusion criteria, 11 articles were selected and analyzed for this review. The articles focus almost exclusively on cognitive reserve, with no explicit connection between sleep and brain or neural reserve. The results evidence sleep's role as a builder of cognitive reserve and cognitive reserve's role as a moderator in the effects of physiological and pathological sleep on cognitive functions. In conclusion, the findings of the present review support the notion that both sleep and cognitive reserve are critical factors in cognitive functioning. Deepening comprehension of the interactions between them is essential for devising strategies to enhance brain health and resilience against age- and pathology-related conditions.

Astrocyte regulation of extracellular space parameters across the sleep-wake cycle.

Multiple subfields of neuroscience research are beginning to incorporate astrocytes into current frameworks of understanding overall brain physiology, neuronal circuitry, and disease etiology that underlie sleep and sleep-related disorders. Astrocytes have emerged as a dynamic regulator of neuronal activity through control of extracellular space (ECS) volume and composition, both of which can vary dramatically during different levels of sleep and arousal. Astrocytes are also an attractive target of sleep research due to their prominent role in the glymphatic system, a method by which toxic metabolites generated during wakefulness are cleared away. In this review we assess the literature surrounding glial influences on fluctuations in ECS volume and composition across the sleep-wake cycle. We also examine mechanisms of astrocyte volume regulation in glymphatic solute clearance and their role in sleep and wake states. Overall, findings highlight the importance of astrocytes in sleep and sleep research.

Exploring the Role of Circadian Rhythms in Sleep and Recovery: A Review Article.

Sleep is essential for every living organism. Humans spend about one-third of their lives sleeping. Sleep has been studied extensively, and the role of sleep in psychological, mental, and physical well-being is established to be the best. The rhythm of the brain between wakefulness and sleep is called the circadian rhythm, which ismainly controlled by melatonin and the pineal gland. The imbalance of this rhythm can lead to devastating effects on health. Vigorous workouts close to bedtime can interfere with falling asleep. Meal timing and composition can significantly affect sleep quality. It is advised to avoid large meals, caffeine, and alcohol before bedtime. Heavy meals close to bedtime can lead to poor sleep and hormone disruption. By following these guidelines enumerated in the article, individuals can improve sleep quality and overall health. Sleep cycles, especially rapid eye movement sleep, have a profound influence on mental and physical health. Adhering to recommended sleep practices enhances bodily restoration, fortifies the immune system, and upholds metabolic equilibrium. Sleep hygiene aligned with circadian rhythms is crucial for disease prevention and well-being. Healthcare professionals should prioritize sleep optimization strategies for patient care and public health.

A quantitative study examining the effects of sleep quality on construction workers’ performance in the city of Jeddah, Saudi Arabia

AbstractPoor sleep and related sleep disorders have been linked to subpar performance in sectors like health and education. Such sleep issues in the workforce negatively affect individual and organisational productivity. Despite this, the high-stress environment of the construction sector has been largely overlooked. This study delves into the role of sleep in construction field management and human resource practices, examining how a better understanding of workers' sleep patterns could enhance job performance. The research involved an online survey of 119 construction workers in the city of Jeddah in Saudi Arabia, focusing on their sleep duration and its impact on job performance, with data analysis conducted using SPSS software. The findings indicate that inadequate sleep influenced by factors such as dietary habits is significantly related to poor performance. The majority of workers are affected by poor sleep quality. The study suggests that construction management should implement health awareness campaigns to improve workers' responsiveness and awareness regarding sleep. It emphasises the need for management to develop strategies to increase sleep awareness and education in the construction industry, aiming to improve overall job performance.

The role of glial and neuronal Eph/ephrin signaling in Drosophila mushroom body development and sleep and circadian behavior

The Eph receptor, a prototypically large receptor protein tyrosine kinase, interacts with ephrin ligands, forming a bidirectional signaling system that impacts diverse brain functions. Eph receptors and ephrins mediate forward and reverse signaling, affecting neurogenesis, axon guidance, and synaptic signaling. While mammalian studies have emphasized their roles in neurogenesis and synaptic plasticity, the Drosophila counterparts are less studied, especially in glial cells, despite structural similarities. Using RNAi to modulate Eph/ephrin expression in Drosophila neurons and glia, we studied their roles in brain development and sleep and circadian behavior. Knockdown of neuronal ephrin disrupted mushroom body development, while glial knockdown had minimal impact. Surprisingly, disrupting ephrin in neurons or glial cells altered sleep and circadian rhythms, indicating a direct involvement in these behaviors independent from developmental effects. Further analysis revealed distinct sleep phenotypes between neuronal and glial knockdowns, underscoring the intricate interplay within the neural circuits that govern behavior. Glia-specific knockdowns showed altered sleep patterns and reduced circadian rhythmicity, suggesting an intricate role of glia in sleep regulation. Our findings challenge simplistic models of Eph/ephrin signaling limited to neuron-glia communication and emphasize the complexity of the regulatory networks modulating behavior. Future investigations targeting specific glial subtypes will enhance our understanding of Eph/ephrin signaling's role in sleep regulation across species.

Retuning of hippocampal representations during sleep.

Hippocampal representations that underlie spatial memory undergo continuous refinement following formation1. Here, to track the spatial tuning of neurons dynamically during offline states, we used a new Bayesian learning approach based on the spike-triggered average decoded position in ensemble recordings from freely moving rats. Measuring these tunings, we found spatial representations within hippocampal sharp-wave ripples that were stable for hours during sleep and were strongly aligned with place fields initially observed during maze exploration. These representations were explained by a combination of factors that included preconfigured structure before maze exposure and representations that emerged during θ-oscillations and awake sharp-wave ripples whileon the maze, revealing the contribution of these events in forming ensembles. Strikingly, the ripple representations during sleep predicted the future place fields of neurons during re-exposure to the maze, even when those fields deviated from previous place preferences. By contrast, we observed tunings with poor alignment to maze place fields during sleep and rest before maze exposure and in the later stages of sleep. In sum, the new decoding approach allowed us to infer and characterize the stability and retuning of place fields during offline periods, revealing the rapid emergence of representations following new exploration and the role of sleep in the representational dynamics of the hippocampus.

The Effect of Melatonin on Appendectomy Postoperative Pain: A Randomized Clinical Trial

Background: Melatonin is synthesized from the tryptophan amino acid in the pineal gland. Its role in sleep has been confirmed in other studies. Several studies have also shown the effect of melatonin on postoperative pain and sedation. This study aimed to evaluate the effect of melatonin on postoperative pain in patients undergoing appendectomy. Methods: In a double-blind clinical trial, 64 patients aged 18–50 years with ASA I/II anesthesia class who were candidates for appendectomy with general anesthesia were enrolled. The patients were randomly divided into two groups: melatonin and placebo (32 people in each group). The first group received 6 mg of oral melatonin one hour before sleep, while the second group received a placebo. Before surgery and 2, 12, and 24 hours after surgery, patients’ pain was measured using the Visual Analogue Scale (VAS). The Ramsay sedation score measured the patients’ sedation, and rescue analgesia was measured at the above time points. SPSS software was used to analyze the data, and P-values&lt;0.05 were considered significant. Results: Our study showed that pain levels in the melatonin group were lower at the 2nd, 12th, and 24th hours after the appendectomy surgery than in the placebo group. Sedation rates were not significantly different between the two groups. Analgesic consumption was lower in the melatonin group than in the placebo group. Conclusion: Melatonin can reduce the degree of pain (VAS) after appendectomy.

Expression of Chemokine Ligands cxcl12a and cxcl12b in the Habenular Region in Danio rerio (zebrafish)

The habenula (Hb) is a bilateral cluster of neurons in the forebrain. The interpeduncular nucleus (IPN) is an important component of the midbrain. Together, they make up the Hb-IPN conduction system. This system plays an important role in sleep, reward-based decision making, and various other behaviors and processes. These important structures are found in all vertebrates, but the understanding of the development of this pathway is in the preliminary stages. Previous studies in zebrafish show that chemokine signaling plays an important role in Hb axonal outgrowth. Chemokine (c-x-c) motif receptor 4b (Cxcr4b), which is made in the dorsal habenula (dHb), helps direct axons toward the IPN. Cxcl12a and Cxcl12b are the two ligands in this signaling pathway, which offer guidance cues to dHb axons, though their functions are not yet entirely clear. cxcl12a mutants show dysfunctional dHb axonal projections, with many axons projecting anteriorly, in the opposite direction of the IPN. Mutants with ectopic cxcl12b expression show similar results. Dorsal views show cxcl12a and cxcl12b are both transcribed in regions posterior to the dHb; cxcl12b is also transcribed anterior to the dHb. However, the relative expression patterns of these ligands is unknown, and may give us a clearer understanding of their respective functions in directing dHb axons. To do this, we will employ in situ hybridization, which will allow us to simultaneously visualize where cxcl12a and cxcl12b are being transcribed along the path of the developing dHb axons.

Enhancing Anaerobic Performance in Kickboxers: The Strategic Role of Short-Duration Napping

The intricate relationship between sleep and athletic performance has long been a subject of interest in sports science. This study delves into the specific impact of short-duration napping on anaerobic performance parameters in the study of kickboxing, an intense combat sport demanding both physical prowess and strategic acumen. We conducted a controlled investigation with 14 young elite male kickboxers, characterized by an average age of 20.29 ± 0.80 years, a height of 174.48 ± 4.11 cm, body masses of 70.46 ± 7.78 kg, and a body mass index (BMI) of 23.12 ± 2.02 kg/m². The experimental design encompassed three distinct conditions: no napping (N0), a 25-minute nap (N25), and a 45-minute nap (N45). The evaluation focused on several key performance metrics, including countermovement jump (CMJ), mean power, and peak power outputs. Intriguingly, our findings indicated that while CMJ values remained relatively unaffected by the napping conditions, significant variations were observed in both mean and peak power outputs, particularly among participants who napped. These variations suggest that napping, even for short durations, can significantly influence certain anaerobic performance parameters in kickboxers, with a marked improvement in power-related aspects. This research contributes to the expanding body of literature on the role of sleep and rest in athletic performance, specifically highlighting the potential of napping as an effective strategy for enhancing physical capabilities in combat sports. The implications of these findings extend beyond the realm of kickboxing, offering valuable insights and practical applications for athletic training and performance optimization across various sports disciplines where anaerobic capabilities are crucial.

Sleeping Problems or Emerging Psychosis? A Review of Emerging Literature

IntroductionSleep disturbance, particularly insomnia, is prevalent across various mental health disorders. While it is a common sign in mood disorders, emerging evidence suggests that insomnia might act as a precursor or an early sign of psychosis. Our case report and literature review emphasize the importance of evaluating sleep disturbances in the diagnosis and management of mental disorders.Objectives-To explore potential neurobiological underpinnings linking sleep disturbances to psychosis onset.-To advocate for the importance of early identification and intervention for sleep disturbances in the broader context of preventing or managing psychotic disorders. Methods We present a case describing a young patient’s first episode of psychosis, which was masked by an initial presentation of insomnia. Additionally, we conducted a review of the relationship between sleep disturbances and psychosis, with a comprehensive literature search from Pubmed, Scopus and psychINFO.Results A 20-year-old African-American male with a history of poor sleep was initially diagnosed with Major Depressive Disorder. He was treated with Bupropion, Quetiapine, and Trazodone. However, he later presented with worsening depression, odd behavior, and signs of disorganization, suggestive of a psychotic episode. After switching his medication to Risperidone 4mg twice daily, the patient’s sleep and other symptoms markedly improved. Through our literature review, we identified that sleep disturbances, especially insomnia, can be a risk factor for developing psychosis. While a cross-sectional study recorded one-fourth of their study population experiencing First Episode Psychosis (FEP) with clinical insomnia, another study reported close to 80% of their study sample with early psychosis suffering from a minimum of one sleep disorder; insomnia and nightmare disorder being the most frequent. A large sample longitudinal analysis lasting one year also observed patients with sleep disorders to be twice at risk of onset and persistence of psychotic episodes. A growing body of evidence also suggests that structural brain abnormalities and neural development alterations in the early stages of psychosis may lead to sleep disturbances and subsequent psychotic symptoms. Findings suggest that thalamic dysfunction may in particular contribute to sleep spindle deficits and altered EEG microstate dynamics. These deficits are unrelated to antipsychotic medication exposure, and are also not observed in patients with other psychiatric illnesses.Conclusions While the correlation between sleep disorders and psychosis has been well-established for decades, very limited literature is available on the role of sleep in FEP. Recognizing and treating sleep disturbances is pivotal in managing psychiatric disorders, including psychosis. Thus, a comprehensive evaluation of sleep issues in patients presenting with psychiatric symptoms is imperative for accurate diagnosis and management.Disclosure of InterestNone Declared