Clocks & Sleep最新文献

The circadian phase difference between morning and evening types is a fundamental aspect of chronotype. However, results of categorizations into chronotypes based on reported sleep times show low concordance with those based on measurements of the hormonal or physiological or molecular rhythm-markers of the circadian phase. This might be partially explained by the profound individual differences in the phase angle between the sleep-wake cycle and these rhythms that depends on chronotype, age, sex, and other factors. Here, we examined the possibility of using self-reported sleep times in the condition of 5-days-on/2-days-off school/work schedule to estimate circadian phase differences between various chronotypes. In an in silico study, we determined that, for such an estimation, similarities of the compared chronotypes in weekend sleep duration and weekend-weekday gap and in risetime are required. In the following empirical and simulation studies of sleep times reported by 4940 survey participants, we provided examples of the estimation of circadian differences between chronotypes, and the model-based simulations of sleep times in morning and evening types exemplified a way to confirm such estimations. The results of in silico, empirical, and simulation studies underscore the possibility of using bedtimes and risetimes for direct estimation of the circadian phase differences between individuals in real-life situations, such as a 5-days-on/2-days-off school/work schedule. Additionally, the results of these studies on different chronotypes provided further mathematical modeling and empirical evidence for our failure to sleep more on weekends to recover/compensate/pay back/ catch up on lost sleep.

Sleep is essential for child development, influencing cognition, emotional regulation, behavior, and physical health. Recent studies increasingly frame sleep as both a key developmental process and a modifiable factor shaped by, and shaping environmental risks-including digital screen exposure and psychosocial stress. This systematic review synthesized empirical findings from cross-sectional and cohort studies published between 2019 and 2024 on the associations between sleep duration, quality, and patterns and developmental outcomes in typically developing children aged 6-12 years. Searches were conducted in EBSCO, Scopus, and Web of Science databases, yielding 99 records, of which 20 met inclusion criteria. Methodological quality was evaluated using Joanna Briggs Institute tools. Findings show consistent associations between better sleep and enhanced cognitive performance, emotional well-being, and reduced behavioral problems. Some studies identified sleep as a mediator between screen use and behavioral difficulties, whit additional moderating effects related to gender and socioeconomic status. However, most studies used cross-sectional designs and self-reported measures, limiting causal interpretation. Overall, sleep emerge as a potentially modifiable factor influencing developmental outcomes, based on correlational evidence. Future research should prioritize longitudinal and ecologically valid designs, objective measures, and computational approaches to identify sleep-related risk profiles and guide early interventions.

Objective: An association between sleep apnea and various urological symptoms has been reported in the literature. Therefore, the aim of this study is to analyze sex-related differences in the association between sleep apnea und subsequent urinary incontinence diagnosis.

Methods: This study examined the incidence of urinary incontinence in a matched pair cohort with and without sleep apnea treated in 1293 general practices in Germany between January 2005 and December 2022 (74,453 vs. 372,256 individuals). The five-year cumulative incidence of urinary incontinence in the cohorts with and without sleep apnea was studied using Kaplan-Meier curves and log-rank tests. Finally, a univariable Cox regression analysis was conducted to assess the association between sleep apnea and urinary incontinence. Stratified analyses were conducted by sex (male/female) and age group (18-50 years, 51-60 years, 61-70 years, >70 years).

Results: Sleep apnea was significantly associated with urinary incontinence as compared to individuals without sleep disorder diagnosis (5.1% vs. 4.3%; p < 0.001), and this association remained robust in females (HR: 1.38; 95% CI: 1.29-1.46), but not in males (HR: 1.02; 95% CI: 0.96-1.08) In females, the association was strongest in the age group 51-60 years (HR: 1.98; 95% CI: 1.71-2.30).

Conclusions: In conclusion, this study reports a significant association between sleep apnea and subsequent urinary incontinence diagnosis. Sex- and age-related differences should be taken into account, as associations were stronger for middle-aged females followed by younger females and no significant association was found regarding males.

Undergraduate students and healthcare professionals often experience irregular sleep patterns, social jet lag (SJL), and rotating shifts that affect their performance. This study examined the association between SJL, sleep duration, and psychosocial factors among 1409 Colombian undergraduate students (mean age 24.4 ± 6.7 years) using data from the Ultra-Short Version of the Munich ChronoType Questionnaire collected between June and September 2023. Multivariable linear regression analysis identified factors associated with SJL. The prevalence of SJL exceeding two hours was high (84.6%), with an average magnitude of 4.4 h. Chronotype (MSFsc) was negatively correlated with SJL, indicating that students with later chronotypes tended to experience greater misalignment between biological and social time. Younger age and a higher number of working days were significantly associated with increased SJL, whereas substance use and mental health history showed no significant effects. These findings highlight that work-related demands, particularly frequent working days, play a key role in exacerbating social jet lag. The results underscore the need for institutional strategies to promote sleep health among Colombian university students and health professionals.

Burnout is increasingly recognized as both a psychosocial and a chronobiological disorder characterized by endocrine dysregulation and circadian disruption. It arises from chronic occupational stress and manifests through psychological, physical, and physiological symptoms. Although psychosocial determinants are well established, the biological and chronobiological mechanisms, particularly those involving cortisol and melatonin, remain less explored. This systematic review synthesizes current evidence on hormonal and circadian dysregulation in burnout and complements it with exploratory observational data from healthcare professionals. Peer-reviewed studies evaluating endocrine or circadian biomarkers in individuals with burnout were systematically reviewed. In addition, an exploratory observational analysis was carried out among 195 Romanian clinicians using an adapted Maslach Burnout Inventory. Morning salivary cortisol was measured once at 9 a.m. in a small subsample (n = 26) to provide preliminary physiological data. Because only a single time point was obtained, these values were interpreted as indicative of stress-related activation rather than circadian rhythm. Thirty-seven studies met the inclusion criteria. Across the literature, burnout was associated with altered HPA-axis activity, blunted diurnal cortisol variation, and irregular melatonin secretion related to shift work and disrupted sleep-wake cycles. Complementary exploratory data from our Romanian cohort indicated strong correlations between burnout severity, physical symptoms, and higher morning cortisol values among shift-working clinicians. These findings are preliminary and not representative of full circadian profiles. Burnout should be considered both a psychosocial and a systemic disorder influenced by endocrine and circadian dysregulation. Recognizing alterations in cortisol and melatonin as objective indicators may facilitate earlier detection and inform chronobiological interventions such as optimized scheduling, light exposure management, or melatonin therapy. The observational data presented here is preliminary and intended to generate hypotheses; future research should employ repeated cortisol sampling under controlled Zeitgeber conditions to confirm circadian associations.

Critically ill patients are predisposed to developing cognitive dysfunction, excessive daytime sleepiness (EDS), and fatigue during their stay in the intensive care unit (ICU). Modafinil, a wakefulness-promoting agent, has demonstrated potential benefits in enhancing alertness, cognitive performance, and activity levels in various clinical populations. The present narrative review aims to systematically evaluate the existing literature regarding the administration of modafinil for the treatment of EDS and fatigue in the ICU context. A comprehensive literature search was performed using the Embase, MEDLINE, Web of Science, and Google Scholar databases, covering publications up to 20 June 2025. Studies investigating the use of modafinil to improve wakefulness in ICU patients were identified. A total of nine relevant studies were included, comprising two randomized controlled trials (RCTs), two case series, and five retrospective cohort studies (n = 950 patients). Four of these studies focused on patients with traumatic brain injury or post-stroke conditions, whereas the remaining studies addressed heterogeneous ICU populations. Preliminary evidence indicates that modafinil may enhance wakefulness in selected critically ill patients and potentially facilitate their participation in rehabilitative interventions, such as physical therapy. Nonetheless, robust conclusions regarding efficacy and safety remain limited by the small sample sizes and methodological constraints of the available studies. Consequently, further large-scale RCTs are warranted to elucidate the therapeutic role of modafinil in the management of EDS and hypoactivity among ICU patients.

Circadian rhythm disruptions from shiftwork impact sleep quality and work performance, yet validated tools to assess circadian preferences in Arabic-speaking populations are scarce. This study aimed to translate and validate the 11-item Circadian Type Inventory (CTI-11) into Arabic (CTI-11A), evaluate its psychometric properties, and explore latent circadian profiles in relation to sleep quality. A cross-sectional survey in Bahrain involved 468 Arabic-speaking adults recruited via social media. The CTI-11A, assessing Languid/Vigorous (LV) and Flexible/Rigid (FR) subscales, and the Jenkins Sleep Scale (JSS) were administered. Confirmatory factor analysis (CFA), reliability tests, and latent class analysis (LCA) were conducted. Participants (mean age: 36.18 ± 10.35) showed CTI-11A total scores of 35.40 ± 6.61 and JSS scores of 5.76 ± 3.48. CFA confirmed the two-factor structure (RMSEA = 0.06, SRMR = 0.05, CFI = 0.93, TLI = 0.91), with Cronbach's α of 0.72 (total CTI-11A). Test-retest reliability was high (ICC = 0.91). CTI-11A correlated moderately with JSS (r = 0.40, p < 0.001), with stronger FR-JSS (r = 0.36) than LV-JSS (r = 0.25) associations. LCA identified two classes (Class 1: 52%, vigorous/flexible; Class 2: 48%, languid/rigid), with Class 2 showing poorer sleep quality. The CTI-11A is a reliable and valid tool for assessing circadian preferences in Arabic-speaking populations, with distinct circadian profiles linked to sleep quality. While flexible/vigorous profiles associated with better sleep, languid/rigid profiles indicate higher sleep disturbance risk, informing targeted shiftwork interventions. Further refinement of the factor structure and broader regional validation are needed.

Background: Shift work necessitates alterations in daily routines, which can be detrimental to workers' health and may also influence the activity and rest patterns of their children.

Aim: The aim of this study was to evaluate the concordance between activity and rest parameters of mothers and their children, according to the mothers' work shift (day vs. night).

Methods: Twelve mother-child dyads participated in this study, including six mothers working night shifts and six working day shifts. All mothers followed a 12/36 h rotating schedule (07:00-19:00 for day shifts; 19:00-07:00 for night shifts). Participants wore actigraphy devices for 10 consecutive days. Sleep and motor activity parameters were analyzed using the Bland-Altman method.

Results: Analysis of the five least active hours (L5) revealed increased nocturnal activity among the night shift group. The period of the 10 most active hours (M10) suggested greater activity in the day shift group, with a smaller difference between mother and child in the day shift group. The relative amplitude (RA) in the night shift group was lower among mothers compared to the day group. Interdaily stability (IS) was lower, and intradaily variability (IV) was higher in the night shift group, suggesting more irregular activity patterns. Bedtime data showed greater variability in the night shift group, with night shift mothers typically going to bed later than their children-a pattern that was also observed for wake times. In the day shift group, total sleep time did not differ between mothers and children; however, in the night shift group, discrepancies increased proportionally with total sleep duration. Sleep efficiency was lower among mothers in both groups, but the difference between mother and child was more pronounced in the night shift group.

Conclusions: Night shift work among mothers appears to negatively affect both their own and their children's activity and sleep parameters when compared to those in the day shift group.

Short sleep duration (≤6 h) is a public health concern linked to cardiometabolic disease and premature mortality. However, persistent disparities across sociodemographic, psychosocial, and structural domains remain underexplored in recent nationally representative samples. We analyzed 2022 Behavioral Risk Factor Surveillance System (BRFSS) data, including 228,463 adults (weighted N ≈ 122 million). Sleep duration was dichotomized as short (≤6 h) versus adequate (≥7 h). Complex samples logistic regression estimated associations between sociodemographic, psychosocial, behavioral, and structural determinants and short sleep, accounting for survey design. The weighted prevalence of short sleep was 33.2%. Non-Hispanic Black (AOR = 1.56, 95% CI: 1.46-1.65) and American Indian/Alaska Native adults (AOR = 1.46, 95% CI: 1.29-1.65) were disproportionately affected compared with non-Hispanic White adults. Psychosocial factors contributed strongly: life dissatisfaction, limited emotional support, and low social connectedness increased odds, whereas high connectedness was protective. Food insecurity and smoking were significant structural and behavioral risks, while binge drinking and urbanicity were not. One-third of U.S. adults report short sleep, with marked disparities across demographic, socioeconomic status, psychosocial stressors, and structural barriers. Findings highlight the multifactorial nature of sleep health inequities and the need for multilevel interventions addressing both individual behaviors and upstream determinants.

Sleep disturbances and shift work are associated with increased cardiovascular risk, possibly through disruptions in endothelial and hemostatic function. While prior studies link acute sleep deprivation to vascular dysfunction, the impact of chronic sleep quality and circadian misalignment on endothelial health in healthy individuals, particularly shift workers, remains underexplored. The aim of this study was to examine the association between objectively measured sleep quality and endothelial/hemostatic function in healthy female hospital nurses, comparing shift and day workers, and considering time-of-day variation. In this repeated-measures study, 100 female nurses (51 shift, 49 day workers) aged 25-50 wore actigraphy devices for 7-14 days to assess total sleep time (TST), sleep efficiency (SEF), and wake after sleep onset (WASO). Endothelial function was measured using EndoPAT (Reactive Hyperemia Index-RHI). Hemostatic markers included plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (VWF), heparanase and heparanase procoagulant activity assessed by ELISA, and chromogenic assays in morning and evening. TST was not associated with any vascular outcomes. Poor sleep quality (low SEF, high WASO) was significantly associated with reduced RHI and elevated PAI-1 level, heparanase level, and heparanase procoagulant activity levels. Regression models revealed significant main effects of SEF and WASO on endothelial and coagulation markers, with some interactions depending on shift type and time of measurement. No significant associations were found for VWF. Impaired sleep quality, but not sleep duration, is associated with endothelial dysfunction and procoagulant activation, particularly among shift-working nurses. These findings suggest that sleep quality may play a critical role in vascular health and support the use of sleep-based interventions to reduce cardiovascular risk in shift-working populations.