Restricted and disrupted sleep: Effects on autonomic function, neuroendocrine stress systems and stress responsivity

Total Joint Arthroplasty and Sleep: The State of the Evidence

Background

As the number of total hip and knee arthroplasties (TJA) performed increases, there is heightened interest in perioperative optimization to improve outcomes. Sleep is perhaps one of the least understood perioperative factors that affects TJA outcomes. The purpose of this article is to review the current body of knowledge regarding sleep and TJA and the tools available to optimize sleep perioperatively.

Methods

A manual search was performed using PubMed for articles with information about sleep in the perioperative period. Articles were selected that examined: sleep and pain in the perioperative period; the effect of surgery on sleep postoperatively; the relationship between sleep and TJA outcomes; risk factors for perioperative sleep disturbance; the effect of anesthesia on sleep; and the efficacy of interventions to optimize sleep perioperatively.

Results

Sleep and pain are intimately associated; poor sleep is associated with increased pain sensitivity. Enhanced sleep is associated with improved surgical outcomes, although transient sleep disturbances are normal postoperatively. Risk factors for perioperative sleep disturbance include increasing age, pre-existing sleep disorders, medical comorbidities, and type of anesthesia used. Interventions to improve sleep include optimizing medical comorbidities preoperatively, increasing sleep time perioperatively, appropriating sleep hygiene, using cognitive behavioral therapy, utilizing meditation and mindfulness interventions, and using pharmacologic sleep aids.

Conclusions

Sleep is one of many factors that affect TJA. As we better understand the interplay between sleep, risk factors for suboptimal sleep, and interventions that can be used to optimize sleep, we will be able to provide better care and improved outcomes for patients.

Heart-brain axis: Pushing the boundaries of cardiovascular molecular imaging

Despite decades of research, the heart-brain axis continues to challenge investigators seeking to unravel its complex pathobiology. Strong epidemiologic evidence supports a link by which insult or injury to one of the organs increases the risk of pathology in the other. The putative pathways have important differences between sexes and include alterations in autonomic function, metabolism, inflammation, and neurohormonal mechanisms that participate in crosstalk between the heart and brain and contribute to vascular changes, the development of shared risk factors, and oxidative stress. Recently, given its unique ability to characterize biological processes in multiple tissues simultaneously, molecular imaging has yielded important insights into the interplay of these organ systems under conditions of stress and disease. Yet, additional research is needed to probe further into the mechanisms underlying the heart-brain axis and to evaluate the impact of targeted interventions.

Sleep quality in relation to perceived psychological stress in patients with type 2 diabetes and in age- and sex-matched control individuals

AIM

To assess sleep quality in relation to perceived stress in patients with type 2 diabetes (T2DM) and age- and sex-matched controls.

METHODS

Perceived stress level and sleep quality assessed in 154 patients with T2DM (58 men, 96 women, age 58.3 ± 11.9 years), 154 matched controls (58 men, 96 women, age 56.8 ± 12.2 years) using Perceived Stress Scale and Pittsburgh Sleep Quality Index.

RESULTS

Patients with T2DM had worse subjective sleep quality (p < 0.001), sleep latency (p = 0.047) than controls. Patients with high stress level had worse subjective sleep quality (p = 0.027), higher use of sleeping medication (p = 0.023), daytime dysfunction (p < 0.001) than those with low stress level. No significant differences in sleep quality between controls with high and low perceived stress level. Perceived stress level in patients with T2DM correlated with subjective sleep quality (r = 0.260, p = 0.002), sleep duration (r = 0.228, p = 0.005), use of sleep medication (r = 0.245, p = 0.004), daytime dysfunction (r = 0.326, p < 0.001), in age- and sex-matched controls-to daytime dysfunction (r = 0.191, p = 0.037).

CONCLUSION

Sleep quality (subjective sleep quality, sleep latency) is worse in patients with type 2 diabetes than in age- and sex-matched controls. Patients with high perceived stress level have worse subjective sleep quality, higher use of sleeping medication, daytime dysfunction than patients with low perceived stress level; no significant differences in sleep quality between controls with high and low stress level. Perceived stress level in patients with type 2 diabetes is related to subjective sleep quality, sleep duration, use of sleep medication, daytime dysfunction, in age- and sex-matched controls-to daytime dysfunction.

Acute sleep deprivation 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 deprivation 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 deprivation 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 hr) that includes and extends beyond periods typically associated with memory consolidation before subjecting them to 6 hr of sleep deprivation. Mice deprived of sleep with this delayed regimen showed dramatic reductions in fear during tests conducted immediately after sleep deprivation, as well as 24 hr later. This sleep deprivation 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 deprivation 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.

Disrupting circadian control of autophagy induces podocyte injury and proteinuria

The circadian clock influences a wide range of biological process and controls numerous aspects of physiology to adapt to the daily environmental changes caused by Earth's rotation. The kidney clock plays an important role in maintaining tubular function, but its effect on podocytes remains unclear. Here, we found that podocytes expressed CLOCK proteins, and that 2666 glomerular gene transcripts (13.4%), including autophagy related genes, had 24-hour circadian rhythms. Deletion of Clock in podocytes resulted in 1666 gene transcripts with the loss of circadian rhythm including autophagy genes. Podocyte-specific Clock knockout mice at age three and eight months showed deficient autophagy, loss of podocytes and increased albuminuria. Chromatin immunoprecipitation (ChIP) sequence analysis indicated autophagy related genes were targets of CLOCK in podocytes. ChIP-PCR further confirmed Clock binding to the promoter regions of Becn1 and Atg12, two autophagy related genes. Furthermore, the association of CLOCK regulated autophagy with chronic sleep fragmentation and diabetic kidney disease was analyzed. Chronic sleep fragmentation resulted in the loss of glomerular Clock rhythm, inhibition of podocyte autophagy, and proteinuria. Rhythmic oscillations of Clock also disappeared in high glucose treated podocytes and in glomeruli from diabetic mice. Finally, circadian differences in podocyte autophagy were also abolished in diabetic mice. Deletion Clock in podocytes aggravated podocyte injury and proteinuria in diabetic mice. Thus, our findings demonstrate that clock-dependent regulation of autophagy may be essential for podocyte survival. Hence. loss of circadian controlled autophagy may play an important role in podocyte injury and proteinuria.

Basal forebrain parvalbumin neurons modulate vigilant attention and rescue deficits produced by sleep deprivation

Attention is impaired in many neuropsychiatric disorders, as well as by sleep disruption, leading to decreased workplace productivity and increased risk of accidents. Thus, understanding the neural substrates is important. Here we test the hypothesis that basal forebrain neurons that contain the calcium-binding protein parvalbumin modulate vigilant attention in mice. Furthermore, we test whether increasing the activity of basal forebrain parvalbumin neurons can rescue the deleterious effects of sleep deprivation on vigilance. A lever release version of the rodent psychomotor vigilance test was used to assess vigilant attention. Brief and continuous low-power optogenetic excitation (1 s, 473 nm @ 5 mW) or inhibition (1 s, 530 nm @ 10 mW) of basal forebrain parvalbumin neurons was used to test the effect on attention, as measured by reaction time, under control conditions and following 8 hr of sleep deprivation by gentle handling. Optogenetic excitation of basal forebrain parvalbumin neurons that preceded the cue light signal by 0.5 s improved vigilant attention as indicated by quicker reaction times. By contrast, both sleep deprivation and optogenetic inhibition slowed reaction times. Importantly, basal forebrain parvalbumin excitation rescued the reaction time deficits in sleep-deprived mice. Control experiments using a progressive ratio operant task confirmed that optogenetic manipulation of basal forebrain parvalbumin neurons did not alter motivation. These findings reveal for the first time a role for basal forebrain parvalbumin neurons in attention, and show that increasing their activity can compensate for disruptive effects of sleep deprivation.

Sleep deprivation reduces the baroreflex sensitivity through elevated angiotensin (Ang) II subtype 1 receptor expression in the nucleus tractus solitarii

Introduction

Sleep insufficiency has been linked to an increased risk of high blood pressure and cardiovascular diseases. Emerging studies have demonstrated that impaired baroreflex sensitivity (BRS) is involved in the adverse cardiovascular effects caused by sleep deprivation, however, the underlying mechanisms remain unknown. Therefore, the present study aims to clarify the role of abnormal renin-angiotensin system in the nucleus tractus solitarii (NTS) in impaired BRS induced by sleep deprivation.

Methods

Rats were randomly divided into two groups: normal sleep (Ctrl) and chronic sleep deprivation (CSD) group. Rats were sleep deprived by an automated sleep deprivation system. The blood pressure, heart rate, BRS, the number of c-Fos positive cells and the expression of angiotensin (Ang) II subtype 1 receptors (AT1R) in the NTS of rats were assessed.

Results

Compared to Ctrl group, CSD group exhibited a higher blood pressure, heart rate, and reduced BRS. Moreover, the number of c-Fos positive cells and local field potential in the NTS in CSD group were increased compared with the Ctrl group. It was shown that the expression of the AT1R and the content of Ang II and the ratio of Ang II to Ang-(1-7) were increased in the NTS of rats in CSD group compared to Ctrl group. In addition, microinjection of losartan into the NTS significantly improved the impaired BRS caused by sleep deprivation.

Discussion

In conclusion, these data suggest that the elevated AT1R expression in the NTS mediates the reduced BRS induced by chronic sleep deprivation.

Temporary relationship between sleep duration and depression and its impact on future risk of cardiovascular disease

BACKGROUND

Although sleep duration and depression were correlated, their temporal sequence and how the sequence influence on future risk of cardiovascular disease (CVD) remained undetermined. This study aimed to explore the temporal relationship between sleep duration and depression, and its association with future CVD risk.

METHODS

We included 10,629 middle-aged and elderly participants with repeated measurements of sleep duration and depressive symptoms (measured by Center for Epidemiological Studies-Depression scale [CESD]) at the first two visits from the China Health and Retirement Longitudinal Study. Cross-lagged analysis and mediation analysis were used to examine the temporal relationship between sleep duration and depression and its impact on future risk of CVD.

RESULTS

The adjusted cross-lagged path coefficient from baseline sleep duration to follow-up CES-D (β1 = -0.191; 95 % confidence interval [CI], -0.239 to -0.142) was significantly greatly than that from baseline CES-D to follow-up sleep duration (β2 = -0.031; 95 % CI, -0.031 to -0.024) (Pdifference < 0.0001). Similarly, the path coefficient from baseline sleep duration to annual changes in CES-D was significantly greater than that from baseline CES-D to annual changes in sleep duration (β1 = -0.093 versus β2 = -0.015, Pdifference < 0.0001). The path coefficient from baseline sleep duration to follow-up CES-D in CVD group was significantly greater than that in those without CVD (Pdifference of β1 = 0.0378). Furthermore, 27.93 % of the total association of sleep duration with CVD was mediated by depression symptoms.

CONCLUSIONS

The findings provide evidence that decrease in sleep duration probably precedes the increased in depressive symptoms, and depression partially mediated the pathway from sleep duration to incident CVD.

Exploring the relationship between sleep and aggression in adolescents: A cross sectional study using the UK Millennium cohort study

This study aimed to establish if a significant relationship exists between sleep and aggression in a large representative adolescent cohort and explores the impact of potential confounders. This cross-sectional secondary data analysis included 10,866 males and females aged 13-15 years, from the UK-based 2015 Millenium Cohort Study (sixth sweep). Independent variables included self-report measures of sleep duration and quality. The parent reported 'Strengths and Difficulties Questionnaire' conduct score measured aggression. Binary logistic regression examined independent associations between each sleep variable and aggression. Multiple regression models then adjusted for potential confounders: age, sex, socioeconomic status, arousal, and affect. Under 8 hours of sleep on average was significantly associated with aggression when age, sex and income were controlled (p = .008). This became insignificant following adjustment for both affect and arousal. Sleep quality remained significantly associated with aggression when all confounders were controlled: 'sleep onset latency >30 minutes' and 'wakening at least a good bit of the time' increased the odds of aggression by around 27.9% (p < .001) and 43.5% respectively (p < .001). A significant association exists between poor subjective sleep quality and heightened aggression in this cohort, when all our confounders are controlled, identifying sleep quality as a potential target in treating adolescent aggression.

Circadian Biology and the Neurovascular Unit

Mammalian physiology and cellular function are subject to significant oscillations over the course of every 24-hour day. It is likely that these daily rhythms will affect function as well as mechanisms of disease in the central nervous system. In this review, we attempt to survey and synthesize emerging studies that investigate how circadian biology may influence the neurovascular unit. We examine how circadian clocks may operate in neural, glial, and vascular compartments, review how circadian mechanisms regulate cell-cell signaling, assess interactions with aging and vascular comorbidities, and finally ask whether and how circadian effects and disruptions in rhythms may influence the risk and progression of pathophysiology in cerebrovascular disease. Overcoming identified challenges and leveraging opportunities for future research might support the development of novel circadian-based treatments for stroke.

Prediction of dementia based on older adults' sleep disturbances using machine learning

BACKGROUND

The most common degenerative condition in older adults is dementia, which can be predicted using a number of indicators and whose progression can be slowed down. One of the indicators of an increased risk of dementia is sleep disturbances. This study aims to examine if machine learning can predict dementia and which sleep disturbance factors impact dementia.

METHODS

This study uses five machine learning algorithms (gradient boosting, logistic regression, gaussian naive Bayes, random forest and support vector machine) and data on the older population (60+) in Sweden from the Swedish National Study on Ageing and Care - Blekinge (n=4175). Each algorithm uses 10-fold stratified cross-validation to obtain the results, which consist of the Brier score for checking accuracy and the feature importance for examining the factors which impact dementia. The algorithms use 16 features which are on personal and sleep disturbance factors.

RESULTS

Logistic regression found an association between dementia and sleep disturbances. However, it is slight for the features in the study. Gradient boosting was the most accurate algorithm with 92.9% accuracy, 0.926 f1-score, 0.974 ROC AUC and 0.056 Brier score. The significant factors were different in each machine learning algorithm. If the person sleeps more than two hours during the day, their sex, education level, age, waking up during the night and if the person snores are the variables that most consistently have the highest feature importance in all algorithms.

CONCLUSION

There is an association between sleep disturbances and dementia, which machine learning algorithms can predict. Furthermore, the risk factors for dementia are different across the algorithms, but sleep disturbances can predict dementia.

Vertebral Subluxation and Systems Biology: An Integrative Review Exploring the Salutogenic Influence of Chiropractic Care on the Neuroendocrine-Immune System

In this paper we synthesize an expansive body of literature examining the multifaceted influence of chiropractic care on processes within and modulators of the neuroendocrine-immune (NEI) system, for the purpose of generating an inductive hypothesis regarding the potential impacts of chiropractic care on integrated physiology. Taking a broad, interdisciplinary, and integrative view of two decades of research-documented outcomes of chiropractic care, inclusive of reports ranging from systematic and meta-analysis and randomized and observational trials to case and cohort studies, this review encapsulates a rigorous analysis of research and suggests the appropriateness of a more integrative perspective on the impact of chiropractic care on systemic physiology. A novel perspective on the salutogenic, health-promoting effects of chiropractic adjustment is presented, focused on the improvement of physical indicators of well-being and adaptability such as blood pressure, heart rate variability, and sleep, potential benefits that may be facilitated through multiple neurologically mediated pathways. Our findings support the biological plausibility of complex benefits from chiropractic intervention that is not limited to simple neuromusculoskeletal outcomes and open new avenues for future research, specifically the exploration and mapping of the precise neural pathways and networks influenced by chiropractic adjustment.

Urban environment influences on stress, autonomic reactivity and circadian rhythm: protocol for an ambulatory study of mental health and sleep

Introduction

Converging evidence suggests that urban living is associated with an increased likelihood of developing mental health and sleep problems. Although these aspects have been investigated in separate streams of research, stress, autonomic reactivity and circadian misalignment can be hypothesized to play a prominent role in the causal pathways underlining the complex relationship between the urban environment and these two health dimensions. This study aims at quantifying the momentary impact of environmental stressors on increased autonomic reactivity and circadian rhythm, and thereby on mood and anxiety symptoms and sleep quality in the context of everyday urban living.

Method

The present article reports the protocol for a feasibility study that aims at assessing the daily environmental and mobility exposures of 40 participants from the urban area of Jerusalem over 7 days. Every participant will carry a set of wearable sensors while being tracked through space and time with GPS receivers. Skin conductance and heart rate variability will be tracked to monitor participants' stress responses and autonomic reactivity, whereas electroencephalographic signal will be used for sleep quality tracking. Light exposure, actigraphy and skin temperature will be used for ambulatory circadian monitoring. Geographically explicit ecological momentary assessment (GEMA) will be used to assess participants' perception of the environment, mood and anxiety symptoms, sleep quality and vitality. For each outcome variable (sleep quality and mental health), hierarchical mixed models including random effects at the individual level will be used. In a separate analysis, to control for potential unobserved individual-level confounders, a fixed effect at the individual level will be specified for case-crossover analyses (comparing each participant to oneself).

Conclusion

Recent developments in wearable sensing methods, as employed in our study or with even more advanced methods reviewed in the Discussion, make it possible to gather information on the functioning of neuro-endocrine and circadian systems in a real-world context as a way to investigate the complex interactions between environmental exposures, behavior and health. Our work aims to provide evidence on the health effects of urban stressors and circadian disruptors to inspire potential interventions, municipal policies and urban planning schemes aimed at addressing those factors.

The pathogenesis of OSA-related hypertension: what are the determining factors?

Sleep-disordered breathing has a relatively high prevalence, which varies from 3-7% in males and from 2-5% in females in the adult population. Studies published in the literature have shown that sleep apnea is closely related to an increased risk of developing various pathologies, among which arterial hypertension stands out. The prevalence of hypertension in patients suffering from obstructive sleep apnea (OSA) ranges from 35-80% and appears to be related to OSA severity. Approximately 40-50% of patients affected by hypertension are also affected by OSA and this association seems to be stronger in young and middle-aged adults (<50 years of age). The primary objective of this narrative review is to provide an update on what are the main contributing comorbidities to the development of a hypertensive state in patients suffering from OSA, an independent risk factor for diurnal hypertension, implicated as a risk factor for the first stroke, recurrent stroke, and post-stroke mortality. There are a lot of factors that contribute to developing a hypertensive state in OSA patients, some more decisive, others less. More evidence from longitudinal studies is needed on the impact of OSA on cardiovascular risk in females, on the causal link between OSA and arterial hypertension or metabolic diseases, like diabetes and glucose intolerance, and the effect of different kinds of OSA treatment.

Sleep, brain systems, and persistent stress in early adolescents during COVID-19: Insights from the ABCD study

PURPOSE

The first year of the COVID-19 pandemic constituted a major life stress event for many adolescents, associated with disrupted school, behaviors, social networks, and health concerns. However, pandemic-related stress was not equivalent for everyone and could have been influenced by pre-pandemic factors including brain structure and sleep, which both undergo substantial development during adolescence. Here, we analyzed clusters of perceived stress levels across the pandemic and determined developmentally relevant pre-pandemic risk factors in brain structure and sleep of persistently high stress during the first year of the COVID-19 pandemic.

METHODS

We investigated longitudinal changes in perceived stress at six timepoints across the first year of the pandemic (May 2020-March 2021) in 5559 adolescents (50 % female; age range: 11-14 years) in the United States (U.S.) participating in the Adolescent Brain Cognitive Development (ABCD) study. In 3141 of these adolescents, we fitted machine learning models to identify the most important pre-pandemic predictors from structural MRI brain measures and self-reported sleep data that were associated with persistently high stress across the first year of the pandemic.

RESULTS

Patterns of perceived stress levels varied across the pandemic, with 5 % reporting persistently high stress. Our classifiers accurately detected persistently high stress (AUC > 0.7). Pre-pandemic brain structure, specifically cortical volume in temporal regions, and cortical thickness in multiple parietal and occipital regions, predicted persistent stress. Pre-pandemic sleep difficulties and short sleep duration were also strong predictors of persistent stress, along with more advanced pubertal stage.

CONCLUSIONS

Adolescents showed variable stress responses during the first year of the COVID-19 pandemic, and some reported persistently high stress across the whole first year. Vulnerability to persistent stress was evident in several brain structural and self-reported sleep measures, collected before the pandemic, suggesting the relevance of other pre-existing individual factors beyond pandemic-related factors, for persistently high stress responses.

Poor Subjective Sleep Quality Predicts Symptoms in Irritable Bowel Syndrome Using the Experience Sampling Method

INTRODUCTION

Sleep quality may affect symptom experience in irritable bowel syndrome (IBS). Our aim was to investigate the relationship between sleep quality and gastrointestinal (GI) symptoms using actigraphy and the experience sampling method.

METHODS

Patients with IBS were recruited from a tertiary Neurogastroenterology clinic and the community. GI symptoms and mood were recorded on a smartphone application, 10 times per day, over 7 consecutive days. Subjective sleep quality was recorded every morning to reflect the night before. Objective measures of sleep quality were estimated from wrist-worn actigraphy. Cross-lagged structural equation models were built to assess the directionality of sleep-symptom relationships over time.

RESULTS

Eighty patients with IBS completed the study (mean age: 37 years [range 20-68], 89% female, 78% community). Approximately 66% had a Pittsburgh Sleep Quality Index score ≥ 8, indicating a clinically significant sleep disturbance. Approximately 82% (95% CI: 72-90) screened positive for a sleep disorder, most commonly insomnia. In cross-lagged analysis, poor subjective sleep quality predicted next-day abdominal pain (0.036 < P < 0.040) and lower GI symptoms (0.030 < P < 0.032), but not vice versa. No significant relationship with GI symptoms was found for any objective sleep measure using actigraphy.

DISCUSSION

Poor subjective sleep quality was associated with higher next-day lower GI symptom levels, but not vice versa. Objective sleep measures did not predict next-day abdominal symptoms, potentially supporting the conclusion that it is the perception of sleep quality that is most influential. This study may be used to guide future research into the effect of sleep interventions on GI symptoms.

Light-Dark and Activity Rhythm Therapy (L-DART) to Improve Sleep in People with Schizophrenia Spectrum Disorders: A Single-Group Mixed Methods Study of Feasibility, Acceptability and Adherence

People with a diagnosis of schizophrenia often have poor sleep, even when their psychotic symptoms are relatively well managed. This includes insomnia, sleep apnoea, hypersomnia, and irregular or non-24 h sleep-wake timing. Improving sleep would better support recovery, yet few evidence-based sleep treatments are offered to this group. This paper presents a mixed methods feasibility and acceptability study of Light-Dark and Activity Rhythm Therapy (L-DART). L-DART is delivered by an occupational therapist over 12 weeks. It is highly personalisable to sleep phenotypes and circumstances. Ten participants with schizophrenia spectrum diagnoses and sleep problems received L-DART; their sleep problems and therapy goals were diverse. We measured recruitment, attrition, session attendance, and adverse effects, and qualitatively explored acceptability, engagement, component delivery, adherence, activity patterns, dynamic light exposure, self-reported sleep, wellbeing, and functioning. Recruitment was ahead of target, there was no attrition, and all participants received the minimum 'dose' of sessions. Acceptability assessed via qualitative reports and satisfaction ratings was good. Adherence to individual intervention components varied, despite high participant motivation. All made some potentially helpful behaviour changes. Positive sleep and functioning outcomes were reported qualitatively as well as in outcome measures. The findings above support testing the intervention in a larger randomised trial ISRCTN11998005.

Lower handgrip strength in short-sleeper individuals with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a frequently observed and remarkably incapacitating disorder worldwide. As a multisystem disorder, OSA has been linked to a plethora of clinical parameters though physical parameters like muscle strength have been scantily studied. Hand grip strength (HGS) is a practical marker of physical function that has been associated with mortality and an array of clinical outcomes as well as physiological parameters like sleep duration. A few seminal studies have observed no link between HGS and OSA severity while no studies evaluated the relationship between objectively determined sleep duration and HGS in OSA.

OBJECTIVE

The present study aimed to evaluate the HGS indices among both OSA severity groups and objectively determined sleep duration groups in OSA.

METHODS

111 treatment-naïve mostly middle-aged individuals with OSA (86 males) were recruited in a tertiary sleep center. Three OSA severity groups were determined by the Apnea-Hypopnea Index while three sleep duration groups were objectively determined by Total Sleep Time (TST). Dominant and non-dominant maximum and average HGS were calculated using a digital hand dynamometer.

RESULTS

Short-sleeper individuals with OSA were found to have lower HGS indices than intermediate or sufficient sleepers with OSA while no differences in HGS indices among OSA severity groups were observed. All HGS indices correlated with TST.

CONCLUSIONS

Future insights can be gleaned from the present results regarding the conceivably transdiagnostic relationship between sleep duration and HGS as well as the potential use of HGS as a marker in OSA.

Understanding the combined effects of sleep deprivation and acute social stress on cognitive performance using a comprehensive approach

Background

Sleep deprivation (SD) and acute social stress are common, often unavoidable, and frequently co-occurring stressors in high-risk professions. Both stressors are known to acutely induce inflammatory responses and an increasing body of literature suggests this may lead to cognitive impairment. This study examined the combined effects of total SD and acute social stress on cognitive performance and took a comprehensive approach to explore their (shared) underlying mechanism leading to cognitive decline.

Method

We recorded cognitive performance on a response inhibition task and a multitask and monitored a range of inflammatory, psychophysiological and self-reported markers in 101 participants, both before and after one night of either sleep (control group: N = 48) or SD (N = 53), and both before and after a social stressor (Trier Social Stress Test).

Results

SD decreased cognitive performance. The social stress test also results in cognitive performance decline in the control group on the response inhibition task, but improved rather than decreased performance of sleep deprived participants on both tasks. The subjective ratings of mental effort also reflect this antagonistic interaction, indicating that the social stressor when sleep-deprived also reduced mental effort. In the inflammatory and physiological measures, this pattern was only reflected by IL-22 in blood. SD reduced blood IL-22 concentrations, and the social stress reduced IL-22 in the control group as well, but not in sleep-deprived participants. There were no interactive effects of SD and social stress on any other inflammatory or psychophysiological measures. The effects of the social stress test on autonomic measures and subjective results suggest that increased arousal may have benefited sleep-deprived participants' cognitive performance.

Discussion

SD generally decreased cognitive performance and increased required mental effort. By contrast, the isolated effects of a social stressor were not generic, showing a positive effect on cognitive performance when sleep deprived. Our study is the first that studied combined effects of sleep deprivation and acute social stress on cognitive performance and inflammatory markers. It provides a comprehensive overview of effects of these stressors on a range of variables. We did not show unequivocal evidence of an underlying physiological mechanism explaining changes in performance due to (the combination of) sleep deprivation and social stress, but consider IL-22 as a possible cytokine involved in this mechanism and certainly worth following up on in future research.

Insomnia and REM sleep instability

In this narrative review, we give an overview of the concept of rapid eye movement sleep instability and its reported implications in the context of insomnia. The term rapid eye movement sleep instability was coined to describe the observation of a modified rapid eye movement quality in insomnia, characterized by an increased tendency of perceiving rapid eye movement sleep as wake, a small but consistent rapid eye movement sleep reduction and an increased rapid eye movement sleep arousal index. Current research highlights relationships that are transdiagnostic in nature, corresponding to the known interaction of insomnia with many psychiatric disorders, and showing relationships to chronic stress and anxiety disorders.

Association between Sleep Quality and Cardiac Autonomic Modulation in Adolescents: A Cross Sectional Study

Objective  To analyze the impact of sleep quality/duration on cardiac autonomic modulation on physically active adolescents with obesity. Materials and Methods  The present cross-sectional study included 1,150 boys with a mean age of 16.6 ± 1.2 years. The assessment of cardiac functions included the frequency domain of heart rate variability (HRV; low frequency - LF; high frequency - HF; and the ratio between these bands -LF/HF -, defined as the sympathovagal balance), and each parameter was categorized as low / high . Physical activity levels and sleep quality/duration were obtained by questionnaires. Abdominal obesity was assessed and defined as waist circumference > 80 th percentile. Results  Poor sleep quality resulted in lower HF (odds ratio [OR]: 1.8; 95% confidence interval [95%CI]: 1.01-3.21]) regardless of physical activity and abdominal obesity. Moreover, the study found no association between sleep duration and HRV parameters in adolescents. Conclusion  Sleep quality, not sleep duration, reduces parasympathetic cardiac modulation apart from other factors such as physical activity and abdominal obesity in adolescents.

Dose-dependent Relationships of Same-day and Typical Substance Use to Sleep Duration in College Cannabis and Alcohol Users: A Multilevel Modeling Approach Using Daily Diary Data

This study characterized how quantities of cannabis and alcohol use affect sleep. Single-day and typical cannabis and alcohol use patterns were considered to assess acute-chronic use interactions. Linear and non-linear associations assessed dose-dependence. College students (n=337; 52% female) provided 11,417 days of data, with up to five time points per day. Daily self-reported sleep duration, cannabis use quantity, and alcohol use quantity were subjected to linear mixed modeling to capture linear and curvilinear associations between single-day and typical use on same-night and typical sleep. Sleep duration (difference between bedtime and waketime) was the outcome. Quantity of cannabis used each day andtypical quantity used across all days were predictors in the cannabis models. Parallel single-day and typical alcohol variables were predictors in the alcohol models. Follow-up analyses excluded days with alcohol-cannabis co-use. Main effects of single-day and typical cannabis quantity on sleep duration were observed when all cannabis-use days were modeled. Higher than typical doses of single-day and typical cannabis were associated with longer sleep durations, but only to a point; at the highest doses, cannabis shortened sleep. A main effect of single-day alcohol quantity and two interactions (single-day use with both linear and curvilinear typical use) on sleep duration were observed when all alcohol-use days were modeled. Greater alcohol consumption on a given day led to shorter same-night sleep, but typically heavier drinkers required higher doses than typically lighter drinkers to experience these adverse effects. Follow-up models suggested alcohol co-use may contribute to the purported sleep-promoting effects of cannabis.

The effect of yoga on insomnia and quality of life among nursing professionals during COVID-19: A pre-post-test interventional study

Background

The coronavirus disease 2019 (COVID-19) pandemic has taken a toll on the well-being and quality of life (QoL) of healthcare professionals, especially nurses. Insomnia, a common consequence of the pandemic, adds to the physical and mental strain on healthcare workers.

Aim

This study aimed to assess the impact of workplace yoga intervention on insomnia severity and QoL among female nursing and healthcare professionals during the pandemic.

Methods

A pre-post-interventional study was conducted among 173 nursing professionals working in a hospital setting. Baseline assessments collected age, body mass index (BMI), insomnia severity using the Insomnia Severity Index (ISI), and QoL using the World Health Organization Quality-of-Life Brief Version (WHOQOL-BREF). A 6-week workplace yoga intervention was conducted by trained professionals, followed by posttest assessments.

Results

Among 173 participants, 57 had insomnia. Participants without significant insomnia had higher QoL scores (P < 0.001). Following the yoga intervention, both subthreshold and moderate clinical insomnia groups experienced reduced insomnia severity (P < 0.001). Quality-of-life scores in the physical, psychological, and environmental domains improved significantly (P < 0.05).

Conclusion

Workplace yoga intervention appears to be a promising approach to alleviate insomnia and enhance QoL among female nursing and healthcare professionals during the COVID-19 pandemic. Implementing tailored workplace yoga programs can play a crucial role in promoting the well-being and resilience of healthcare workers, contributing to a positive work environment and improved patient care outcomes.

Homeostatic control of deep sleep and molecular correlates of sleep pressure in Drosophila

Homeostatic control of sleep is typically addressed through mechanical stimulation-induced forced wakefulness and the measurement of subsequent increases in sleep. A major confound attends this approach: biological responses to deprivation may reflect a direct response to the mechanical insult rather than to the loss of sleep. Similar confounds accompany all forms of sleep deprivation and represent a major challenge to the field. Here, we describe a new paradigm for sleep deprivation in Drosophila that fully accounts for sleep-independent effects. Our results reveal that deep sleep states are the primary target of homeostatic control and establish the presence of multi-cycle sleep rebound following deprivation. Furthermore, we establish that specific deprivation of deep sleep states results in state-specific homeostatic rebound. Finally, by accounting for the molecular effects of mechanical stimulation during deprivation experiments, we show that serotonin levels track sleep pressure in the fly's central brain. Our results illustrate the critical need to control for sleep-independent effects of deprivation when examining the molecular correlates of sleep pressure and call for a critical reassessment of work that has not accounted for such non-specific effects.

Sleep characteristics before assisted reproductive technology treatment predict reproductive outcomes: a prospective cohort study of Chinese infertile women

Sleep disorders affect mental and physical health. Infertile women undergoing assisted reproductive technology (ART) treatment are prone to sleep disorders. Sleep condition, its influencing factors, and the association between sleep condition and ART treatment outcomes before treatment have not been explored within a population with a large sample size. Therefore, we investigated the sleep characteristics of 1002 Chinese infertile women before ovulation induction and investigated the influencing factors (negative and positive psychological factors, demographics, and fertility characteristics). We also examined whether sleep conditions before treatment predicted reproductive outcomes. We found that 24.1% of participants reported poor sleep quality. Women with primary infertility reported poorer sleep than women with secondary infertility. Negative psychological factors, including depression, anxiety, and perceived stress were associated with poor sleep, whereas positive affect was linked with good sleep. Adverse sleep characteristics, including poor subjective sleep quality, sleep disturbances, and poor sleep efficiency, decreased the quantity and quality of oocytes retrieved, fertilization rates, and clinical pregnancy rates. This study indicates that before ART treatment, a large number of females with infertility suffer from sleep problems, which are affected by psychological factors and infertility type, and unhealthy sleep characteristics may impair treatment outcomes. Our findings highlight the importance of screening and treatment for sleep disorders before the enrollment of ART treatment in infertile women.

Reverse genetic screening during L1 arrest reveals a role of the diacylglycerol kinase 1 gene dgk-1 and sphingolipid metabolism genes in sleep regulation

Sleep is a fundamental state of behavioral quiescence and physiological restoration. Sleep is controlled by environmental conditions, indicating a complex regulation of sleep by multiple processes. Our knowledge of the genes and mechanisms that control sleep during various conditions is, however, still incomplete. In Caenorhabditis elegans, sleep is increased when development is arrested upon starvation. Here, we performed a reverse genetic sleep screen in arrested L1 larvae for genes that are associated with metabolism. We found over 100 genes that are associated with a reduced sleep phenotype. Enrichment analysis revealed sphingolipid metabolism as a key pathway that controls sleep. A strong sleep loss was caused by the loss of function of the diacylglycerol kinase 1 gene, dgk-1, a negative regulator of synaptic transmission. Rescue experiments indicated that dgk-1 is required for sleep in cholinergic and tyraminergic neurons. The Ring Interneuron S (RIS) neuron is crucial for sleep in C. elegans and activates to induce sleep. RIS activation transients were abolished in dgk-1 mutant animals. Calcium transients were partially rescued by a reduction-of-function mutation of unc-13, suggesting that dgk-1 might be required for RIS activation by limiting synaptic vesicle release. dgk-1 mutant animals had impaired L1 arrest survival and dampened expression of the protective heat shock factor gene hsp-12.6. These data suggest that dgk-1 impairment causes broad physiological deficits. Microcalorimetry and metabolomic analyses of larvae with impaired RIS showed that RIS is broadly required for energy conservation and metabolic control, including for the presence of sphingolipids. Our data support the notion that metabolism broadly influences sleep and that sleep is associated with profound metabolic changes. We thus provide novel insights into the interplay of lipids and sleep and provide a rich resource of mutants and metabolic pathways for future sleep studies.

Within-person relationships of sleep duration with next-day stress and affect in the daily life of adults with Type-1 diabetes

OBJECTIVE

The objective of this study is to examine the within-person relationships between sleep duration and next-day stress and affect in the daily life of individuals with T1D.

METHODS

Study participants were recruited in the Function and Emotion in Everyday Life with Type 1 Diabetes (FEEL-T1D) study. Sleep duration was derived by synthesizing objective (actigraphy) and self-report measures. General and diabetes-specific stress and positive and negative affect were measured using ecological momentary assessment. Multilevel regression was used to examine the within-person relationships between sleep duration and next-day stress and affect. Cross-level interactions were used to explore whether gender and baseline depression and anxiety moderated these within-person relationships.

RESULTS

Adults with T1D (n = 166) completed measurements for 14 days. The average age was 41.0 years, and 91 participants (54.8%) were female. The average sleep duration was 7.3 h (SD = 1.2 h). Longer sleep was significantly associated with lower general stress (p < 0.001) but not diabetes-specific stress (p = 0.18) on the next day. There were significant within-person associations of longer sleep with lower levels on next-day negative affect (overall, p = 0.002, disappoint, p = 0.05; sad, p = 0.05; tense, p < 0.001; upset, p = 0.008; anxious, p = 0.04). There were no significant associations with positive affect. Examination of the interaction effects did not reveal significant differential relationships for men and women and for individuals with and without depression or anxiety at baseline.

CONCLUSION

Findings from this study suggest optimizing sleep duration as an important interventional target for better managing general stress and improving daily emotional wellbeing of individuals with T1D.

Sleep disturbance, but not depression severity, is associated with inflammation in children and adolescents

STUDY OBJECTIVES

We aimed to examine the association between self-rated and clinician-rated sleep disturbances and C-reactive protein (CRP), an objective marker of inflammation, in pediatric depression.

METHODS

Two hundred fifty-six children and adolescents (15.2 ± 1.6 y, 72.3% female) with moderate to severe symptoms of depression participated in the study. Sleep disturbances were assessed by self-reports (Insomnia Severity Index) and clinician ratings (Kiddie-Schedule for Affective Disorder and Schizophrenia), inflammation by plasma CRP levels.

RESULTS

Higher levels of CRP correlated positively with clinician-rated middle insomnia and hypersomnia. After adjusting for control variables (body mass index, tobacco, alcohol, stress, age, sex, antidepressants, sleep medication, depression severity), regression models confirmed the significant association of clinician-rated hypersomnia and middle insomnia symptoms with elevated CRP levels. In the adjusted regression models, other clinician-rated manifestations of sleep disturbance (eg, initial insomnia) and insomnia self-ratings were not significantly associated with CRP. Body mass index correlated positively with CRP, but body mass index had no mediating effect on the associations between sleep disturbances and CRP. We did not find an association between depression severity, assessed by the Children's Depression Rating Scale-Revised, and CRP.

CONCLUSIONS

Results of the present study indicate a significant association of hypersomnia and middle insomnia symptoms with CRP in pediatric depression, not linked to alterations in the body mass index.

CITATION

Strumberger MA, Häberling I, Emery S, et al. Sleep disturbance, but not depression severity, is associated with inflammation in children and adolescents. J Clin Sleep Med. 2023;19(10):1775-1784.

Research hotspots and trends on sports medicine of athletes: A scientometric analysis from 2003 to 2023

This study aims to demonstrate current research priorities and predict future trends of sports medicine of athletes by scientometric analysis. We collected nearly 20 years (2003 to 2023) of publications related to Sports medicine of athletes in the Web of Science database, Citespace was applied to evaluate the knowledge mapping. There are 4820 manuscripts about post-cesarean section in total, and faster growth after 2018. The country, institution, and author posted the most are the USA, Harvard University, and Engebretsen, Lars. Brit J Sport Med publishes the most articles of this type. In addition, the most key cited reference is Hopkins WG (2009). Sports medicine of athletes research, including blood, biomedical imaging informatics, and activity monitor has been a research hotspots in recent years. Through scientometric analysis of the past 20 years, we know the blood, biomedical imaging informatics, and activity monitor is the focus of future research. The USA, Australia, and England have become the main research forces in this field with high publication rates and centrality. This is important for accurately and quickly locating trends in this field.

Sleep impairment and altered pattern of circadian biomarkers during a long-term Antarctic summer camp

Antarctic expeditions include isolation and exposure to cold and extreme photoperiods (with continuous natural light during summer) that may influence psychophysiological responses modulated by luminosity and sleep. We assessed changes in night sleep patterns by actigraphy, salivary biomarkers, and perceptual variables in seven participants in the following time points along a 50-day camping expedition in Antarctica (Nelson Island): Pre-Field (i.e., on the ship before camp), Field-1, Field-2, Field-3, Field-4 (from 1st to 10th, 11th to 20th, 21st to 35th and 36th to 50th days in camp, respectively), and Post-Field (on the ship after camp). We also characterized mood states, daytime sleepiness, and sleep quality by questionnaires. Staying in an Antarctic camp reduced sleep efficiency (5.2%) and increased the number of awakenings and wakefulness after sleep onset (51.8% and 67.1%, respectively). Furthermore, transient increases in time in bed (16.5%) and sleep onset latency (4.8 ± 4.0 min, from Pre- to Field-3) was observed. These changes were accompanied by an altered pattern of the emerging circadian marker β-Arrestin-1 and a trend to reduce nocturnal melatonin [57.1%; P = 0.066, with large effect size (ES) from Pre-Field to Field-2 (ES = 1.2) and Field-3 (ES = 1.2)]. All changes returned to Pre-Field values during the Post-Field. The volunteers reported sleep-related physical complaints (feeling of cold and pain, discomfort to breathe, and cough or loud snoring), excessive daytime sleepiness, and reduced vigor during the camp. Thus, a 50-day camp alters neuroendocrine regulation and induces physical discomfort, which may explain the impaired sleep pattern and the consequent daytime sleepiness and mood changes.

The Relationship between Allergic Disease and Sexual Dysfunction: A Scoping Review

INTRODUCTION

Sexual dysfunction (SD) and allergic disease are common health concerns worldwide and bear a potential relationship. This scoping review is conducted to analyze the currently available data regarding the associations between these two health issues.

METHODS

A comprehensive literature search was performed in the databases of PubMed, MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science to retrieve studies that were published before January 2023. A narrative synthesis was conducted to analyze the effects of allergic diseases on SD based on the evaluation of the Female Sexual Function Index (FSFI) and International Index of Erectile Function (IIEF).

RESULTS

Twelve observational studies were included after the selection process. The results generally suggested lower FSFI or IIEF scores in patients with asthma, allergic rhinitis, allergic rhinoconjunctivitis, and urticaria compared to the healthy control groups. The underlying factors of this relationship could be inflammation, psychological factors, hormonal changes, sleep disorders, sexual behavior-related allergic reactions, social economic status, and the use of medications.

CONCLUSION

SD and allergic disease are interrelated based on the extant literature. This scoping review provides insights into the clinical implications of both entities, while more research studies are warranted to further elucidate this complex relationship.

Narrative review: The role of circadian rhythm on sports performance, hormonal regulation, immune system function, and injury prevention in athletes

Objectives

This study was a narrative review of the importance of circadian rhythm (CR), describes the underlying mechanisms of CR in sports performance, emphasizes the reciprocal link between CR, endocrine homeostasis and sex differences, and the unique role of the circadian clock in immune system function and coordination.

Method

As a narrative review study, a comprehensive search was conducted in PubMed, Scopus, and Web of Science (core collection) databases using the keywords "circadian rhythm", "sports performance", "hormonal regulation", "immune system", and "injury prevention". Inclusion criteria were studies published in English and peer-reviewed journals until July 2023. Studies that examined the role of CR in sports performance, hormonal status, immune system function, and injury prevention in athletes were selected for review.

Results

CR is followed by almost all physiological and biochemical activities in the human body. In humans, the superchiasmatic nucleus controls many daily biorhythms under solar time, including the sleep-wake cycle. A body of literature indicates that the peak performance of essential indicators of sports performance is primarily in the afternoon hours, and the evening of actions occurs roughly at the peak of core body temperature. Recent studies have demonstrated that the time of day that exercise is performed affects the achievement of good physical performance. This review also shows various biomarkers of cellular damage in weariness and the underlying mechanisms of diurnal fluctuations. According to the clock, CR can be synchronized with photonic and non-photonic stimuli (i.e., temperature, physical activity, and food intake), and feeding patterns and diet changes can affect CR and redox markers. It also emphasizes the reciprocal links between CR and endocrine homeostasis, the specific role of the circadian clock in coordinating immune system function, and the relationship between circadian clocks and sex differences.

Conclusion

The interaction between insufficient sleep and time of day on performance has been established in this study because it is crucial to balance training, recovery, and sleep duration to attain optimal sports performance.

Methods for Heart Rate Variability Biofeedback (HRVB): A Systematic Review and Guidelines

Heart Rate Variability Biofeedback (HRVB) has been widely used to improve cardiovascular health and well-being. HRVB is based on breathing at an individual's resonance frequency, which stimulates respiratory sinus arrhythmia (RSA) and the baroreflex. There is, however, no methodological consensus on how to apply HRVB, while details about the protocol used are often not well reported. Thus, the objectives of this systematic review are to describe the different HRVB protocols and detect methodological concerns. PsycINFO, CINALH, Medline and Web of Science were searched between 2000 and April 2021. Data extraction and quality assessment were based on PRISMA guidelines. A total of 143 studies were finally included from any scientific field and any type of sample. Three protocols for HRVB were found: (i) "Optimal RF" (n = 37), each participant breathes at their previously detected RF; (ii) "Individual RF" (n = 48), each participant follows a biofeedback device that shows the optimal breathing rate based on cardiovascular data in real time, and (iii) "Preset-pace RF" (n = 51), all participants breathe at the same rate rate, usually 6 breaths/minute. In addition, we found several methodological differences for applying HRVB in terms of number of weeks, duration of breathing or combination of laboratory and home sessions. Remarkably, almost 2/3 of the studies did not report enough information to replicate the HRVB protocol in terms of breathing duration, inhalation/exhalation ratio, breathing control or body position. Methodological guidelines and a checklist are proposed to enhance the methodological quality of future HRVB studies and increase the information reported.

Effects of Supplementation with the Standardized Extract of Saffron (affron®) on the Kynurenine Pathway and Melatonin Synthesis in Rats

Melatonin is a hormone that regulates sleep-wake cycles and is mainly synthesized in the pineal gland from tryptophan after its conversion into serotonin. Under normal conditions, less than 5% of tryptophan is reserved for the synthesis of serotonin and melatonin. The remaining 95% is metabolized in the liver through the kynurenine pathway. Increased levels of proinflammatory cytokines and cortisol increase the metabolism of tryptophan through the kynurenine pathway and reduce its availability for the synthesis of melatonin and serotonin, which may cause alterations in mood and sleep. The standardized saffron extract (affron®) has shown beneficial effects on mood and sleep disorders in humans, but the underlying mechanisms are not well understood. Thus, the aim of this work was to study the effects of affron® supplementation on the kynurenine pathway and the synthesis of melatonin in rats. For this purpose, adult male Wistar rats were supplemented for 7 days with 150 mg/kg of affron® or vehicle (2 mL/kg water) administered by gavage one hour before sleep. Affron® supplementation reduced body weight gain and increased the circulating levels of melatonin, testosterone, and c-HDL. Moreover, animals supplemented with affron® showed decreased serum levels of kynurenine, ET-1, and c-LDL. In the pineal gland, affron® reduced Il-6 expression and increased the expression of Aanat, the key enzyme for melatonin synthesis. In the liver, affron® administration decreased the mRNA levels of the enzymes of the kynurenine pathway Ido-2, Tod-2, and Aadat, as well as the gene expression of Il-1β and Tnf-α. Finally, rats treated with affron® showed increased mRNA levels of the antioxidant enzymes Ho-1, Sod-1, Gsr, and Gpx-3, both in the liver and in the pineal gland. In conclusion, affron® supplementation reduces kynurenine levels and promotes melatonin synthesis in rats, possibly through its antioxidant and anti-inflammatory effects, making this extract a possible alternative for the treatment and/or prevention of mood and sleep disorders.

Sleep quality moderates the association between family bereavement and heart rate variability

Two separate bodies of literature point to the link between family bereavement and cardiovascular health and between sleep quality and cardiovascular outcomes. However, less is known about the joint influence of family bereavement and sleep quality on cardiovascular functioning. The aims of this study were to examine the relationships between experiencing the death of a family member and heart rate variability (HRV) and to further explore whether these associations differ by sleep quality. Using data from the Midlife in the United States (MIDUS) Biomarker Project, the sample for this study included respondents who experienced the death of an immediate family member - father, mother, spouse, sibling, or child - within a year before the Biomarker project and those who did not experience any deaths (N = 962). We used two measures of HRV and sleep quality was measured using the Pittsburgh Sleep Quality Index. Results showed that experiencing the death of a family member was associated with worse HRV only among those with poor sleep quality and not for those with good sleep quality. These results suggest that poor sleep quality may indicate psychophysiological vulnerability for those who experienced the death of a family member. Interventions to improve sleep quality could be effective in enhancing cardiovascular health of bereaved individuals.

Sleep disorders among patients suffering from road traffic injuries in an urban setting of Vietnam: an exploratory study

Sleep quality is an important indicator of treatment outcome for patients with traffic accident injuries. In Vietnam, the impacts of injury on sleep status are usually amplified in urban areas due to disproportionate distribution of mental care services between the city and less developed settings. Our study investigated deterioration in sleep quality and identified associated demographic factors among traffic injury patients in an small urban setting of Vietnam. A cross-sectional study was conducted among 408 patients in one provincial hospital and five district hospitals in Thai Binh, Vietnam from October to December 2018. A structured questionnaire was designed based on 3 standardized scales: Health-related Quality of Life, the Pittsburgh Sleep Quality Index and the Kessler Scale. Face-to-face interviews and medical records were conducted by trained health professionals on patients hospitalized in the Trauma-Orthopedic/Burn Department and Surgery and General Department. About 16.9% of respondents had sleep disturbances, and there was a statistically significant difference between age group (p < 0.01), education level (p < 0.01), and monthly household income (p < 0.01) between participants who with and without sleep disturbances. Furthermore, more than half (50.7%) of respondents sleep less than 5 h per day, while 18.7% of the sampled also reported that the habitual sleep efficiency was below 85%. Current results indicated that people being female, suffering from traumatic brain injury, being comatose at hospitalization, and having higher psychological distress scores were more likely to suffer from sleep problems. Our study is one of the first evidence in Vietnam to assess sleep disturbances in road traffic injury patients and their correlated factors. It is important to identify patients who are at risk of sleep disturbances based on socio-demographic and clinical characteristics, as well as psychological distress status. Therefore, a holistic approach should be taken to include sleep quality and psychological state in the treatment process and outcome assessment for road traffic injury patients.

Reciprocal Effects between Sleep Quality and Life Satisfaction in Older Adults: The Mediating Role of Health Status

OBJECTIVES

to examine the causal relationship between sleep quality and life satisfaction and explore the mediating role of health status on the relationship between sleep quality and life satisfaction.

METHODS

A total of 1856 older Chinese people participating in 2011, 2014, and 2018 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were included. A cross-lagged panel analysis (CLPA) combined with mediator analysis was utilized.

RESULTS

The average sleep quality levels for the years 2011, 2014, and 2018 were 3.70, 3.63, and 3.47 out of 5, respectively. The corresponding average levels of health status were 3.47, 3.44, and 3.39 out of 5, and the average levels of life satisfaction were 3.75, 3.86, and 3.87 out of 5, respectively. In addition, sleep quality at prior assessment points was significantly associated with life quality at subsequent assessments, and vice versa. Also, health status partially mediated this prospective reciprocal relationship.

CONCLUSIONS

There is a nonlinear decreased trend in sleep quality and health status, while there exists a nonlinear increased trend in life satisfaction for older adults from 2011 to 2018. Reciprocal positive effects between sleep quality and life satisfaction in older adults exist and are mediated by health status.

The Relationship between Insomnia and the Pathophysiology of Major Depressive Disorder: An Evaluation of a Broad Selection of Serum and Urine Biomarkers

Insomnia exhibits a clinically relevant relationship with major depressive disorder (MDD). Increasing evidence suggests that insomnia is associated with neurobiological alterations that resemble the pathophysiology of MDD. However, research in a clinical population is limited. The present study, therefore, aimed to investigate the relationship between insomnia and the main pathophysiological mechanisms of MDD in a clinical sample of individuals with MDD. Data were extracted from three cohorts (N = 227) and included an evaluation of depression severity (Quick Inventory of Depressive Symptomatology, QIDS-SR₁₆) and insomnia severity (QIDS-SR₁₆ insomnia items) as well as serum and urine assessments of 24 immunologic (e.g., tumour necrosis factor α receptor 2 and calprotectin), neurotrophic (e.g., brain-derived neurotrophic factor and epidermal growth factor), neuroendocrine (e.g., cortisol and aldosterone), neuropeptide (i.e., substance P), and metabolic (e.g., leptin and acetyl-L-carnitine) biomarkers. Linear regression analyses evaluating the association between insomnia severity and biomarker levels were conducted with and without controlling for depression severity (M = 17.32), antidepressant use (18.9%), gender (59.0% female; 40.5% male), age (M = 42.04), and the cohort of origin. The results demonstrated no significant associations between insomnia severity and biomarker levels. In conclusion, for the included biomarkers, current findings reveal no contribution of insomnia to the clinical pathophysiology of MDD.

Bidirectional association between sleep quality or duration and aggressive behaviour in early adolescents: A cross-lagged longitudinal study

BACKGROUND

Several cross-sectional studies have suggested a strongly positive link between sleep and aggressive behaviour; however, longitudinal studies reporting the relationship between sleep and aggressive behaviour are lacking. This study aimed to examine whether a bidirectional relationship exists between sleep quality or duration and aggressive behaviour in early adolescents.

METHODS

A total of 1579 early adolescents (60.9 % boys) from the Chinese Early Adolescents Cohort study were included in this study. Data on sleep quality, sleep duration and aggressive behaviour collected at two time points (September 2019 and September 2021) were used, and the bidirectional relationship between sleep quality or duration and aggressive behaviour was examined using a cross-lagged model.

RESULTS

The results revealed a bidirectional relationship between low sleep quality and highly aggressive behaviour. A shorter sleep duration did not predict highly aggressive behaviour, whereas only highly aggressive behaviour predicted a shorter sleep duration.

CONCLUSIONS

Sleep quality and aggressive behaviour were interrelated over time among adolescents. However, sleep duration did not predict aggressive behaviour, suggesting that sleep quality, instead of sleep duration, should be the primary target for managing aggressive behaviour.

The stress of losing sleep: Sex-specific neurobiological outcomes

Sleep is a vital and evolutionarily conserved process, critical to daily functioning and homeostatic balance. Losing sleep is inherently stressful and leads to numerous detrimental physiological outcomes. Despite sleep disturbances affecting everyone, women and female rodents are often excluded or underrepresented in clinical and pre-clinical studies. Advancing our understanding of the role of biological sex in the responses to sleep loss stands to greatly improve our ability to understand and treat health consequences of insufficient sleep. As such, this review discusses sex differences in response to sleep deprivation, with a focus on the sympathetic nervous system stress response and activation of the hypothalamic-pituitary-adrenal (HPA) axis. We review sex differences in several stress-related consequences of sleep loss, including inflammation, learning and memory deficits, and mood related changes. Focusing on women's health, we discuss the effects of sleep deprivation during the peripartum period. In closing, we present neurobiological mechanisms, including the contribution of sex hormones, orexins, circadian timing systems, and astrocytic neuromodulation, that may underlie potential sex differences in sleep deprivation responses.

The effect of coffee and black tea consumption on sleep bruxism intensity based on polysomnographic examination

Background

Sleep bruxism (SB) is a common behavior that can result in various clinical consequences on human health. Risk factors for SB include among others emotional stress, anxiety, tobacco smoking, and excessive alcohol consumption. Coffee and black tea are among the most commonly consumed beverages worldwide. This study explores the influence of coffee and black tea consumption on bruxism intensity, as observed in polysomnographic examination.

Methods

Polysomnographic examination with simultaneous camera recording was conducted in 106 adult subjects. The results were evaluated according to guidelines set out by the American Academy of Sleep Medicine (AASM). The study group was divided according to habitual stimulant usage, as declared by the participants in a self-reported questionnaire. Four groups were identified: coffee drinkers versus non-drinkers and black tea drinkers versus non-drinkers.

Results

The bruxism episode index (BEI) was increased in coffee-drinkers as opposed to non-drinkers (4.59 ± 3.44 vs. 2.87 ± 1.50, p = 0.011). Sleep fragmentation, measured according to the arousal index, was comparable in coffee drinkers and non-drinkers. Electrolyte and lipid levels were similar in coffee drinkers and non-drinkers. Habitual black tea intake did not affect sleep architecture or bruxism intensity.

Conclusions

The study showed that habitual coffee consumption is a risk factor for the increased intensity of sleep bruxism. Neither coffee nor tea consumption is related to sleep fragmentation in habitual drinkers. Coffee and tea intake does not affect electrolyte and lipid concentrations. Caution should therefore be recommended in drinking coffee in people with sleep bruxism.

Stress, hypothalamic pituitary adrenal axis activity and autonomic nervous system function in adolescents with insomnia

INTRODUCTION

Abnormal stress responses have been linked to the etiology of insomnia. We investigated the relationship between insomnia, stress, hypothalamic-pituitary-adrenal (HPA) axis activity, and autonomic nervous system (ANS) function in adolescence.

METHODS

Forty-seven post-pubertal adolescents (16-20 years old, 28 female) with (N = 16; insomnia group) and without (N = 31; control group) DSM-5 insomnia symptoms were assessed for stress levels and stress reactivity and underwent a standardized stress protocol (Trier Social Stress Test (TSST)), after an overnight laboratory stay. Cortisol was measured upon awakening and 30-minutes later to calculate the cortisol awakening response (CAR). During the TSST, perceived stress, salivary cortisol (HPA activity), heart rate (HR) and blood pressure (BP) measures were collected.

RESULTS

Participants in the insomnia group reported more stress from school performance and work overload, with insomnia girls experiencing more stress from peer pressure and future uncertainty than control girls (p < 0.05). No group differences were detected in the CAR and pre-TSST stress levels. All participants showed significant increases in perceived stress (~19 %), HR (~33 %), systolic (~13 %), and diastolic (~15 %) BP in response to the TSST (p < 0.05). Overall HR stress response did not differ between groups, but was lower in boys with insomnia than in girls with insomnia (p < 0.05). Cortisol stress responses were inconclusive, possibly due to a masking effect of CAR, as the task was performed shortly after awakening and larger CARs were associated with blunted cortisol stress responses.

DISCUSSION

Results mostly show no group difference in physiological stress responses, although some interaction effects suggest a potential sex by insomnia interaction. Larger samples are needed to understand the physiological disturbances of insomnia in adolescence.

The association of cortisol/testosterone ratio and sleep quality with coronary heart disease: A case-control study in Chinese rural population

PURPOSE

There were limited studies that have probed into the combined effect of the cortisol/testosterone (C/T) ratio as a biomarker of stress and Pittsburgh Sleep Quality Index (PSQI) on coronary heart disease (CHD). This research aimed to explore the association of C/T ratio and PSQI with the risk of CHD in a rural Chinese population, as well as the interaction and combined effect between C/T ratio and PSQI on CHD.

METHODS

A case-control study was performed including 307 individuals without CHD and 307 patients drawn from Henan Rural Cohort. Logistic regression was utilized to survey the independent and joint effects of the C/T ratio and PSQI on CHD. To estimate the interaction impact of the C/T ratio and sleep quality (PSQI) on CHD, a cross-product term was introduced in the generalized linear model.

RESULTS

Higher C/T ratio and PSQI index scores are related to increased odds ratio for CHD (Odds ratios (ORs) and 95 % confidence interval (CI) were 1.17 (1.07, 1.29), p-trend < 0.001; 1.16 (1.09, 1.22), respectively). The odds ratio of C/T ratio for CHD increased with increasing PSQI in women (pinteraction = 0.018) and total population (pinteraction = 0.033). The combined group of high C/T ratio and high PSQI had the highest risk of CHD (Total: OR = 7.53, 95 % CI: 4.12-13.76).

CONCLUSIONS

The risk of CHD was associated with low testosterone levels, high C/T ratios, and high PSQI scores. Additionally, poor sleep quality aggravated the effect of high C/T ratio on coronary heart disease.

Sleep characteristics and inflammatory markers in women with post-traumatic stress disorder

INTRODUCTION

Sexual violence is one of the most severe traumatic events. It is associated with a higher risk for post-traumatic stress disorder (PTSD) development. Sleep disturbances such as insomnia are frequently reported by PTSD patients and play a key role in the development and course of the disorder. Sleep disturbances are associated with higher levels of pro-inflammatory cytokines emphasizing the importance of sleep studies in individuals with PTSD.

OBJECTIVES

To investigate the association between subjective and objective sleep measurements and PTSD symptoms with inflammatory markers in women with PTSD following sexual assault.

METHODS

In this longitudinal study fifty-seven women with PTSD were evaluated for sleep measurements and inflammatory markers. Participants completed the Clinician-Administered PTSD Scale, the Beck Depression Inventory, the Pittsburgh Sleep Quality Index (PSQI), and the Insomnia Severity Index. In addition, patients underwent full in-lab polysomnography and serum levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP) measurement. All assessments were performed at baseline and after one year. Patients received pharmacological and/or psychological interventions between baseline and one-year follow-up.

RESULTS

Despite improving PTSD symptoms severity and sleep quality (expressed in PSQI), we found an increase in the inflammatory markers IL-1β, TNF-α, IL-6 and CRP after one year of follow-up. These findings suggest that neurobiological processes may advance independently of PTSD symptoms. We found a significant increase in the levels of IL-1β and TNF-α associated with decreased slow-wave sleep (p = 0.019 and p = 0.018 respectively), IL-6 associated with arousal index (p = 0.024), and CRP associated with insomnia severity (p = 0.012), and sleep duration longer than 6 h per night (p < 0.001).

CONCLUSIONS

Sleep impairments in PTSD may be associated with a gradual and persistent alteration in the immune system, resulting in a progressive inflammatory process. Our results suggest that sleep mechanisms are involved in this incident inflammatory process in young women with PTSD.

OSA and Subsequent Risk of Hospitalization With Pneumonia, Respiratory Infection, and Total Infection: The Atherosclerosis Risk in Communities Study

BACKGROUND

OSA has been linked to microaspiration, systemic inflammation, and suboptimal immune function.

RESEARCH QUESTION

Is OSA prospectively associated with risk of hospitalization for pneumonia, respiratory, and total infections?

STUDY DESIGN AND METHODS

Prospective cohort. Participants in the Atherosclerosis Risk in Communities (ARIC) study (N = 1,586) underwent polysomnography in 1996-1998 and were followed up through 2018 for infection-related hospitalizations. The apnea-hypopnea index (AHI; events/h) was used to categorize participants as having severe OSA (≥ 30), moderate OSA (15-29), mild OSA (5-14), or a normal breathing pattern (< 5). Cox regression was used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

ARIC participants were on average 62.7 (SD = 5.5) years of age, and 52.8% were female. Severe OSA was present in 6.0%, moderate OSA in 12.7%, mild OSA in 30.0%, and normal breathing in 51.3%. A total of 253 hospitalizations with pneumonia occurred over a median 20.4 (max, 22.9) years' follow-up. Participants with severe OSA were at 1.87 times (95% CI, 1.19-2.95) higher risk of hospitalization with pneumonia compared with those with a normal breathing pattern after adjustment for demographics and lifestyle behaviors. Results were attenuated modestly after adjustment for BMI (1.62 [0.99-2.63]), and prevalent asthma and COPD (1.62 [0.99-2.63]). A similar pattern existed for hospitalization with respiratory infection and composite infection (demographic and behavior-adjusted HRs: 1.47 [0.96-2.25] and 1.48 [1.07-2.04], respectively).

INTERPRETATION

Severe OSA was associated with increased risk of hospitalizations with pneumonia in this community-based cohort. OSA patients may benefit from more aggressive efforts to prevent pneumonia and other infectious conditions.

Gut microbiota: A new target of traditional Chinese medicine for insomnia

All species have a physiological need for sleep, and sleep is crucial for the preservation and restoration of many physiological processes in the body. Recent research on the effects of gut microbiota on brain function has produced essential data on the relationship between them. It has been discovered that dysregulation of the gut-brain axis is related to insomnia. Certain metabolites of gut microbiota have been linked to insomnia, and disturbances in gut microbiota can worsen insomnia. Traditional Chinese medicine (TCM) has unique advantages for the treatment of insomnia. Taking the gut microbiota as the target and determining the scientific relevance of TCM to the prevention and treatment of insomnia may lead to new concepts for the treatment of sleep disorders and improve the therapeutic effect of sleep. Taking the gut microbiota as an entry point, this paper reviews the relationship between gut microbiota and TCM, the relationship between gut microbiota and insomnia, the mechanism by which gut microbiota regulate sleep, and the mechanism by which TCM regulates gut microbiota for insomnia prevention and treatment. This review provides new ideas for the prevention and treatment of insomnia through TCM and new ideas for drug development.

Sleep deprivation induces structural changes in the adult rat testis: The protective effects of olive oil

OBJECTIVE

Sleep deprivation (SD) is a common problem in today's stressful lifestyle and have physiological consequences, including reproductive dysfunction and infertility. As an antioxidant, olive oil may be effective in reducing testicular and spermatological damage by decreasing the production of free radicals.

METHODS

This study investigated the effects of olive oil on sperm quality and testicular structure using stereological methods to assess rats with SD.

RESULTS

When comparing SD group to grid floor+distilled water (GR) group, we found that the sperm count and motility, as well as the percentage of slow progressive sperm was significantly lower in SD group (p<0.05), but the percentage of immotile sperm was higher (p<0.01). However, no improvement was observed in sperm count or motility after concomitant treatment of SD group with olive oil. Stereological examinations revealed no significant change in the total volumes of the seminiferous tubules, interstitial tissue, and germinal epithelium in the study groups. Conversely, the total number of testicular cell types was significantly lower in SD group than in GR group. Although the total number of Sertoli and Leydig cells was significantly higher in the SD+olive oil group than in the untreated SD group, no significant difference in the total number of other testicular cell types was observed between the two groups.

CONCLUSION

SD potentially induced structural changes in testis that affected sperm count and motility. However, olive oil only improved the total number of Sertoli and Leydig cells in the animals with SD and did not improve sperm count and motility.

Night-Time Heart Rate Variability during an Expedition to Mt Everest: A Case Report

Mt Everest has been gaining popularity from casual hiking athletes, climbers, and ultra-endurance marathon runners. However, living and sleeping at altitude increases the risk of injury and illness. This is because travel to high altitudes adversely affects human physiology and performance, with unfavourable changes in body composition, exercise capacity, and mental function. This is a case report of a climber who reached the summit of Mt Everest from the north side. During his 40-day expedition, we collected sleep quality data and night-time heart rate variability. During the night inside the tent, the air temperature ranged from -12.9 to 1.8 °C (-5.8 ± 4.9 °C) and the relative humidity ranged from 26.1 to 78.9% (50.7 ± 16.9%). Awake time was 17.1 ± 6.0% of every sleep-time hour and increased with altitude (r = 0.42). Sleep time (r = -0.51) and subjective quality (r = 0.89) deteriorated with altitude. Resting heart rate increased (r = 0.70) and oxygen saturation decreased (r = -0.94) with altitude. The mean NN, RMSSD, total power, LF/HF, and SD1 and SD2 were computed using the NN time series. Altitude reduced the mean ΝΝ (r = -0.73), RMSSD (r = -0.31), total power (r = -0.60), LF/HF ratio (r = -0.40), SD1 (r = -0.31), and SD2 (r = -0.70). In conclusion, this case report shows that sleeping at high altitudes above 5500 m results in progressively reduced HRV, increased awakenings, as well as deteriorated sleep duration and subjective sleep quality. These findings provide further insight into the effects of high altitude on cardiac autonomic function and sleep quality and may have implications for individuals who frequently spend time at high altitudes, such as climbers.