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Aims: Sleep timing, influenced by chronotype, behavior, and circadian rhythms, is critical for human health. While previous research has linked chronotype to various health outcomes, the impact of aligning sleep timing with chronotype on physical health remains underexplored. The objective of this study is to investigate the association between chronotype, actual sleep timing, and their alignment with a spectrum of physical health outcomes., Methods: Objective sleep timing (actigraphy, categorized as early, intermediate, or late) and chronotype (self-reported, categorized as morning, intermediate, or evening types) were derived from the UK Biobank (n=73,888 middle-aged and older adults) and used in cross-sectional and longitudinal analyses. Physical health outcomes included metabolic disorders, diabetes, obesity, hypertension, circulatory disorders, digestive disorders, respiratory disorders, and all-cause cancer based on ICD10 codes. Analyses were adjusted for demographic factors, sleep duration and sleep timing stability., Results: As compared to morning types with early behavior (aligned), morning types with late behavior (misaligned) had an increased risk of all included physical health disorders (p's<0.001). As compared to evening-types with late behavior (aligned), however, evening-types with early behavior (misaligned) had a decreased risk of diabetes, obesity, hypertension, circulatory disorders, and respiratory disorders (p < 0.01). Longitudinal analyses, in which the likelihood of developing de novo physical health disorders was associated with chronotype, behavioral timing, and alignment between the two, confirmed cross-sectional findings., Conclusion: Late sleep timing across chronotypes was consistently associated with adverse physical health outcomes. These findings underscore the importance of going to sleep early, regardless of preference., Competing Interests: Declaration of competing interest The authors have declared that no conflict of interest exists., (Copyright © 2024. Published by Elsevier B.V.)

Background: Sleep is impaired in children with attention-deficit/hyperactivity disorder (ADHD). However, population-based examination of indicators of sleep insufficiency and bedtime irregularity is limited. This investigation examined associations between ADHD, weeknight sleep insufficiency, and bedtime irregularity in a nationally-representative child sample, and indicators of these sleep outcomes in ADHD., Methods: Parents of children aged 3-17 years with ADHD (n = 7671) were surveyed through the 2020-2021 National Survey of Children's Health. Inverse probability of treatment weighting generated a weighted matched control sample (n = 51,572). Weighted generalized linear models were performed without and with age-stratification to examine associations between ADHD and sleep, adjusting for sociodemographics in the full sample, and between nineteen sociodemographic and clinical variables and sleep in ADHD., Results: Having ADHD was associated with increased odds of sleep insufficiency and bedtime irregularity relative to controls, even after adjusting for sociodemographic variables. In ADHD, older age was associated with lower sleep insufficiency and greater bedtime irregularity. Black race, increased poverty, higher ADHD severity, depression, and increased screen time were associated with greater sleep insufficiency and bedtime irregularity. Adverse childhood experiences (ACEs) were associated with greater sleep insufficiency. Behavioral/conduct problems, female sex, and absence of both ADHD medication use and ASD diagnosis were associated with poorer bedtime irregularity. Age-stratified results are reported in text., Conclusions: Children with ADHD face heightened risk for insufficient sleep and irregular bedtimes. Findings suggest intervention targets (e.g., Black race, poverty, depression, screen time) to improve both sleep insufficiency and bedtime irregularity. Results highlight ACEs and behavioral/conduct problems as targets to improve sleep insufficiency and bedtime regularity, respectively. Age-stratified findings are discussed., Competing Interests: Declaration of competing interest EJR reports financial support was provided in part by the National Institute of Mental HealthK23MH113884. SKL reports financial support was provided in part by the National Institute of Mental HealthR01MH126041. EJR reports grants from the American Academy of Sleep Medicine, Brain and Behavior Research Foundation, and National Institute of Mental Health, relevant to the submitted work. She also reports speaking and lecture fees from Wink Sleep. SKL reports a grant from the National Institute of Mental Health relevant to the submitted work. TYL, SB, VSS, DSJ, KAK, and JMZ declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The circadian wake drive is a mathematic representation of the observed increased propensity to stay awake late in the day, peaking in the hours just before anticipated bed time. It has been called the "forbidden zone" due to the difficulty in initiating sleep during this time and is responsible for the problems initiating sleep when traveling eastward, for maintaining daytime sleep in shift workers, and for initiating sleep in some individuals with insomnia. Evidence culled from studies in individuals with narcolepsy, who lack production of hypocretin (orexin) neuropeptides, as well as a primate model of human wake consolidation and pharmacologic studies of hypocretin antagonists indicate that hypocretin-1 may be the physiologic instantiation of the circadian wake drive. This review will discuss the evidence in support of this hypothesis., (Published by Elsevier Inc.)

Objectives: There has been a proliferation in the use of commercially-available accelerometry- and heart rate-based wearable devices to monitor sleep. While the underlying technology is reasonable at detecting sleep quantity, the ability of these devices to predict subjective sleep quality is currently unknown. We tested whether the fundamental signals from such devices are useful in determining subjective sleep quality., Methods: Older, community-dwelling men (76.5 ± 5.77 years) enrolled in the Osteoporotic Fractures in Men Study (MrOS) participated in an overnight sleep study during which sleep was monitored with actigraphy (wrist-worn accelerometry) and polysomnography (PSG), including electrocardiography (N = 1141). Subjective sleep quality was determined the next morning using 5-point Likert-type scales of sleep depth and restfulness. Lasso and random forest regression models analyzed the relationship between actigraph-determined sleep variables, the shape of the activity patterns during sleep (functional principal component analysis), average heart rate, heart rate variability (HRV), demographics, and self-reported depression, anxiety, habitual sleep, and daytime sleepiness measures., Results: Actigraphy data, in combination with heart rate, HRV, demographic, and psychological variables, do not predict well subjective sleep quality (R 2  = 0.025 to 0.162)., Conclusions: Findings are consistent with previous studies that objective sleep measures are not well correlated with subjective sleep quality. Developing validated biomarkers of subjective sleep quality could improve both existing and novel treatment modalities and advance sleep medicine towards precision healthcare standards., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives: In older adults, traditional metrics derived from polysomnography (PSG) are not well correlated with subjective sleep quality. Little is known about whether the association between PSG and subjective sleep quality changes with age, or whether quantitative electroencephalography (qEEG) is associated with sleep quality. Therefore, we examined the relationship between subjective sleep quality and objective sleep characteristics (standard PSG and qEEG) across middle to older adulthood., Methods: Using cross-sectional analyses of 3173 community-dwelling men and women aged between 39 and 90 participating in the Sleep Heart Health Study, we examined the relationship between a morning rating of the prior night's sleep quality (sleep depth and restfulness) and polysomnographic, and qEEG descriptors of that single night of sleep, along with clinical and demographic measures. Multivariable models were constructed using two machine learning methods, namely lasso penalized regressions and random forests., Results: Little variance was explained across models. Greater objective sleep efficiency, reduced wake after sleep onset, and fewer sleep-to-wake stage transitions were each associated with higher sleep quality; qEEG variables contributed little explanatory power. The oldest adults reported the highest sleep quality even as objective sleep deteriorated such that they would rate their sleep better, given the same level of sleep efficiency. Despite this, there were no major differences in the predictors of subjective sleep across the age span., Conclusion: Standard metrics derived from PSG, including qEEG, contribute little to explaining subjective sleep quality in middle-aged to older adults. The objective correlates of subjective sleep quality do not appear to systematically change with age despite a change in the relationship between subjective sleep quality and objective sleep efficiency., (Published by Elsevier B.V.)

Background: Sleep disturbance is prevalent among women with metastatic breast cancer (MBC). Our study examined the relationship of depression and marital status to sleep assessed over three nights of polysomnography (PSG)., Methods: Women with MBC (N=103) were recruited; they were predominately white (88.2%) and 57.8±7.7 years of age. Linear regression analyses assessed relationships among depression, marital status, and sleep parameters., Results: Women with MBC who reported more depressive symptoms had lighter sleep (e.g., stage 1 sleep; P<.05), less slow-wave sleep (SWS) (P<.05), and less rapid eye movement (REM) sleep (P<.05). Single women had less total sleep time (TST) (P<.01), more wake after sleep onset (WASO) (P<.05), worse sleep efficiency (SE) (P<.05), lighter sleep (e.g., stage 1; P<.05), and less REM sleep (P<.05) than married women. Significant interactions indicated that depressed and single women had worse sleep quality than partnered women or those who were not depressed., Conclusion: Women with MBC and greater symptoms of depression had increased light sleep and reduced SWS and REM sleep, and single women had worse sleep quality and greater light sleep than married counterparts. Marriage was related to improved sleep for women with more depressive symptoms., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Scheduled exposure to bright light (phototherapy) has been used, with varying degrees of success, to treat sleep disruption in older individuals. Most of these studies have been done in institutional settings and have used several hours of daily light exposure. Such a regimen in the home setting may be untenable, especially when the individual with the sleep disruption has memory impairment and is being cared for by a family member. As such, we examined the effectiveness of a "user-friendly" phototherapy protocol that would be readily usable in the home environment., Methods: We exposed a group of 54 older caregiver/care recipient dyads, in which the care recipient had memory impairment, to two weeks of morning bright light phototherapy. Dyads were exposed to either bright white (∼4200 lux) or dim red (∼90 lux) light for 30 min every day, starting within 30 min of rising. All subjects also received sleep hygiene therapy. Objective (actigraphy) and subjective measures of sleep and mood were obtained at baseline and at the end of the two weeks of phototherapy., Results: In care recipients, actigraphy- and log-determined time in bed and total sleep time declined in the active condition (p<0.05, ANOVA); there was no corresponding change in subjective insomnia symptoms (p's>0.37, ANOVA). The decrease in the time in bed was associated with an earlier out of bed time in the morning (p<0.001, Pearson correlation). The decrease in the total sleep time was associated with a decrease in sleep efficiency (p<0.001, Pearson correlation) and an increase in wake after sleep onset (p<0.001, Pearson correlation). In caregivers, there were no differential changes in actigraphic measures of sleep (p's>0.05, ANOVA). Actigraphy-measured wake after sleep onset and sleep efficiency did, however, improve in both conditions, as did sleepiness, insomnia symptoms, and depressive symptomatology (p's<0.05, ANOVA)., Conclusions: Exposure to this regimen of phototherapy diminished sleep in older individuals with memory impairments. Their caregivers, however, experienced an improvement in sleep and mood that appeared independent of the phototherapy and likely due to participation in this protocol or the sleep hygiene therapy., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: To examine the validity of a novel caffeine intake questionnaire and to examine the effects of caffeine on sleep in college students., Methods: One-week, ad libitum behavior of 50 university students (28 female, 22 male; aged 20.9 ± 1.78 years) was examined with sleep logs, wrist actigraphy, and a novel daily questionnaire assessing caffeine intake at different times of day. Saliva samples were collected for caffeine assessment (questionnaire validation) and DNA extraction, and for analysis of a single nucleotide polymorphism in the adenosine receptor 2A (ADORA2A) gene., Results: The caffeine questionnaire was able to accurately predict salivary concentrations of caffeine (R(2) = 0.41, P<0.001). Estimations of integrated salivary caffeine concentration during sleep were correlated with wake after sleep onset (WASO) most strongly in morning-type individuals (R(2) = 0.49; P<0.001, ANOVA), less so in intermediate chronotypes (R(2) = 0.16; P<0.001, ANOVA), and not significantly in evening-types (R(2) = 0.00098; P = 0.13, ANOVA). Using multivariate modeling methods we found that the ADORA2A genotype did not moderate the effects of caffeine on WASO, but did independently alter WASO such that those with the CC genotype had nearly three-times as much WASO as those with CT or TT., Conclusions: Our questionnaire was able to accurately predict salivary caffeine concentrations and helped to describe a novel relationship between the effects of caffeine on sleep and genotype and chronotype., (Published by Elsevier B.V.)

Objective: To examine the effect of ambulatory daytime light exposure on phase delays and on the advances produced by timed exposure to bright evening or morning light., Methods: As a subset of a larger study, 32 older (63.0 ± 6.43 years) adults with primary insomnia were randomized to an at-home, single-blind, 12-week, parallel-group study entailing daily exposure to 45 min of scheduled evening or morning bright (∼4000 lux) light. Light exposure patterns during the baseline and the last week of treatment were monitored using actigraphs with built-in illuminance detectors. Circadian phase was determined through analysis of in-laboratory collected plasma melatonin., Results: Less daytime light exposure during the last week of treatment was significantly associated with larger phase delays in response to evening light (r's>0.78). Less daytime light exposure during the last week of treatment was also associated with a significant delay in wake time (r's>-0.75). There were no such relationships between light exposure history and phase advances in response to morning light., Conclusions: Greater light exposure during the daytime may decrease the ability of evening light, but not morning light, exposure to engender meaningful changes of circadian phase., (Published by Elsevier B.V.)

Background: The hypothalamic neuropeptide hypocretin (orexin) modulates sleep-wake, feeding and endocrine functions. Cerebrospinal fluid (CSF) hypocretin-1 (Hcrt-1) concentrations are low in patients with narcolepsy-cataplexy, a sleep disorder characterized by hypersomnolence and rapid eye movement (REM) sleep abnormalities., Methods: We determined CSF Hcrt-1 concentrations of patients with the fibromyalgia syndrome (FMS), a condition characterized by fatigue, insomnia and in some cases daytime hypersomnolence., Results: Basal CSF levels of Hcrt-1 in FMS did not differ from those in healthy normal controls., Conclusions: These findings suggest that abnormally low Hcrt-1 is not a likely cause of fatigue in FMS.