Sleep in Normal Aging

Relationship between shift type and sleep quality in rotating-shift nurses with chronotype as a moderator variable

BACKGROUND

Rotating-shift nurses are susceptible to sleep disorders due to numerous factors, such as their biological clock, emotions, and age. At present, a lack of research exists on whether chronotype and shift type jointly influence the sleep quality of nurses.

AIM

To verify whether chronotype is a moderator variable of the relationship between shift type and sleep quality in nurses in order to provide empirical evidence for future mental and physical health improvement.

METHOD

Clinical rotating-shift nurses at a medical center in northern Taiwan were recruited as participants between November 1, 2023, and December 13, 2023. All of the nurses were working a monthly rotating shift schedule. Hierarchical multiple regression analysis was employed to investigate whether the influence of shift type on sleep quality in nurses varied with chronotype. The STROBE checklist was used for reporting this study.

RESULTS

The participants were 255 rotating-shift nurses in this study. Hierarchical multiple regression results revealed that rotating-shift nurses who were older (B = 0.19, p = 0.029), had greater physical fatigue (B = 0.27, p = 0.016), and had more negative emotions (B = 0.17, p = 0.011) suffered from poorer sleep quality. After controlling the above factors, we further found that chronotype indeed had moderating effects on the influence of shift type on sleep quality (B = -1.83, p = 0.049).

CONCLUSIONS

This study demonstrates that early- and intermediate-type nurses are more suitable for working the day and evening shifts, whereas late-type nurses are more suitable for working the night shift.

IMPLICATION FOR NURSING AND HEALTH POLICY

Coordinating chronotype with shift type will ensure that shift schedules better match the biological clocks of nurses; such individual considerations could help to improve their sleep quality.

Sleep Characteristics, Magnetic Resonance Imaging- and Dual-Energy X-Ray Absorptiometry-Based Morphological Parameters, Muscle Strength, and Risk of Falls in Sedentary Older Subjects

BACKGROUND

The aims of this cross-sectional study were to (a) assess actigraphy-based sleep parameters (total sample and gender differences), (b) assess differences in morphological parameters and physical function between short- versus normal-sleepers and poor- versus good-sleepers, and (c) assess the possible correlations between sleep variables and morphological and physical function parameters in older subjects.

METHODS

This study enrolled 42 healthy older participants (60-80 years). Participants completed the following clinical evaluations: (1) whole-body dual-energy X-ray absorptiometry to assess the appendicular skeletal muscle mass index; (2) magnetic resonance imaging acquisition to determine the cross-sectional muscle area of thigh muscles and intermuscular adipose tissue; (3) risk of fall assessment through the mini-Balance Evaluation Systems Test; (4) strength assessment: (a) chair stand test and (b) handgrip strength test; (5) sleep monitoring by actigraphy to assess total sleep time, sleep efficiency, wake after sleep onset, sleep latency, fragmentation index, mobile time, and subjective sleep quality.

RESULTS

31.0% of subjects were short-sleepers (total sleep time < 6 hr), 19.1% were poor-sleepers (sleep efficiency < 85%), and gender differences were detected in mobile time (males: 15.8 ± 6.0 and females: 13.4 ± 6.8; p < .001) and fragmentation index (males: 35.3 ± 14.3 and females: 29.6 ± 14.6; p < .001); no significant differences were observed between groups (short- vs. normal-sleepers and poor- vs. good-sleepers) in morphological and physical function variables; correlation analysis showed that sleep latency negatively correlated with Mini-Balance Evaluation Systems Test (r = -.352; p = .022) and a positive correlation was detected between cross-sectional muscle area and mobile time (r = .349, p = .023).

CONCLUSION

No differences were observed in morphological and function parameters between good- versus poor-sleepers, those subjects with worse sleep onset latency (i.e., longer time to fall asleep) registered higher for risk of fall. The potential role of sleep in the physiological mechanisms of muscular aging must be explored through cross-sectional cohort studies with a larger population.

Mechanism of action of Panax ginseng alcohol extract based on orexin-mediated autophagy in the treatment of sleep and cognition in aged sleep-deprived rats

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng (P. ginseng) C. A. Meyer. has been used extensively globally as a medicine. It has a therapeutic effect on sleep and is an attractive alternative for patients with insomnia. The United States Patent of Invention has approved the use of P. ginseng alcohol extract (GAE) in nutraceuticals or food to improve sleep. It has shown promise as an effective therapeutic agent for improving sleep and cognition. However, its mechanism of action is not yet fully understood.

AIM OF THE STUDY

To investigate the therapeutic benefits of GAE on sleep and cognition and its underlying mechanism in aged sleep-deprived rats, with a focus on orexin-mediated autophagy function.

MATERIALS AND METHODS

We conducted in vivo tests in an aged sleep-deprivation rat model produced using p-chlorophenylalanine (PCPA) coupled with modified multi-platform method to examine the therapeutic effects and mechanisms of GAE. A pentobarbital sodium-induced sleep test and water maze were used to assess sleep and cognitive performance, respectively. An enzyme-linked immunosorbent assay was used to determine orexin levels and aging and sleep markers in serum and hypothalamic tissues. Hematoxylin-eosin staining and Nissl staining were used to assess histopathological changes, and autophagy levels were assessed using transmission electron microscopy, immunofluorescence. Western blot and immunohistochemical staining were performed to detect the levels of orexin, orexin-receptor proteins, and autophagy-associated proteins to study the effects of GAE on hippocampal neurons, and the underlying mechanisms.

RESULTS

In aged sleep-deprived rats, GAE treatment prolonged sleep duration, improved cognitive function, prevented hippocampal neuronal damage, increased the number of Nissl bodies, improved aging and sleep markers, and enhanced the LC3A/B expression in autophagosomes and neurons. The amount of orexin in serum and hypothalamic tissue and OX1R, OX2R, and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) proteins also reduced, which resulted in the inhibition of the PI3K/Akt/mTOR pathway and activation of the autophagy process.

CONCLUSIONS

GAE may reduce hypothalamic orexin secretion and interact with orexin receptors to inhibit the PI3K/Akt/mTOR signalling network and activate autophagy. This may be a potential mechanism of action of GAE in regulating sleep-related cognitive function.

Effects of 24-h sleep deprivation on whole-body heat exchange in young men during exercise in the heat

Sleep deprivation has been associated with impaired thermoregulatory function. However, whether these impairments translate to changes in whole-body heat exchange during exercise-heat stress remains unknown. Therefore, following either a night of normal sleep or 24 h of sleep deprivation, 10 young men (mean (SD): 23 (3) years) completed three 30-min bouts of semi-recumbent cycling at increasing fixed rates of metabolic heat production (150, 200, 250 W/m2), each separated by a 15-min rest in dry heat (40 °C, ~ 13% relative humidity). Rates (W/m2) of whole-body total heat exchange (dry + evaporative) were measured continuously and expressed as peak responses [mean of the final 5-min of exercise at the highest metabolic heat production (250 W/m2)]. Body heat storage was quantified as the temporal summation of heat production and loss. Core temperature, indexed by rectal temperature, was measured continuously. Relative to normal sleep, sleep deprivation did not modify whole-body heat exchange (evaporative (-6 [-18, 5] W/m2; P = 0.245), or dry (7 [-5, 19] W/m2; P = 0.209; sleep deprivation-normal sleep mean difference [95%CIs]) and therefore total heat loss (1 [-14, 15] W/m2; P = 0.917). There were no differences in either the change in body heat storage (-9 [-67, 49] kJ; P = 0.732) or change in core temperature (0.1 [-0.1, 0.3] °C; P = 0.186) between conditions. Overall, we showed that 24-h sleep deprivation did not influence whole-body dry or evaporative heat exchange, resulting in no differences in total whole-body heat exchange or body heat storage in young adults during exercise under hot-dry conditions.

Impact of Varying Sleep Pressure on Daytime Sleep Propensity in Healthy Young and Older Adults

Fixed sleep schedules with an 8 h time in bed (TIB) are used to ensure participants are well-rested before laboratory studies. However, such schedules may lead to cumulative excess wakefulness in young individuals. Effects on older individuals are unknown. We combine modelling and experimental data to quantify the effects of sleep debt on sleep propensity in healthy younger and older participants. A model of arousal dynamics was fitted to sleep data from 22 young (20-31 y.o.) and 26 older (61-82 y.o.) individuals (25 male) undertaking 10 short sleep-wake cycles during a 40 h napping protocol, following >1 week of fixed 8 h TIB schedules. Homeostatic sleep drive at the study start was varied systematically to identify best fits between observed and predicted sleep profiles for individuals and group averages. Daytime sleep duration was the same on the two days of the protocol within the groups but different between the groups (young: 3.14 ± 0.98 h vs. 3.06 ± 0.75 h, older: 2.60 ± 0.98 h vs. 2.37 ± 0.64 h). The model predicted an initial homeostatic drive of 11.2 ± 3.5% (young) and 10.1 ± 3.5% (older) above well-rested. Individual variability in first-day, but not second-day, sleep patterns was explained by the differences in the initial homeostatic drive for both age groups. Our study suggests that both younger and older participants arrive at the laboratory with cumulative sleep debt, despite 8 h TiB schedules, which dissipates after the first four sleep opportunities on the protocol. This has implications for protocol design and the interpretation of laboratory studies.

Analyzing sex-specific differences in sleep quality, resilience, and biomarkers among older adults in the Gan-Dau Healthy Longevity Plan

BACKGROUND

Limited knowledge exists regarding the interrelations between sleep quality and resilience within the demographic of healthy, community-residing middle-aged and older adults, with a particular dearth of information regarding sex-specific associations. This study aimed to examine the sex-specific associations between sleep quality, resilience, and biomarkers in community-dwelling middle-aged and older adults.

METHODS

This cross-sectional study was conducted using data from the 2022 Gan-Dau Healthy Longevity Plan survey initiated by the locality-based community hospital, Taipei Municipal Gan-Dau Hospital (TMGDH). A total of 770 participants (240 men, 530 women) who met the inclusion criteria were included in the study. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), while resilience was measured using the Brief Resilience Scale (BRS). Patient demographic data, including age, education, marital status, and depression level, were also collected. The sex-specific associations between sleep quality and resilience were first examined using multivariate generalized linear models (GLMs). In addition, the associations between sleep quality, resilience, and selected biomarkers were examined using multivariate GLMs.

RESULTS

Approximately 55% of men and 60% of women reported poor sleep quality. Individuals with good sleep quality had significantly lower levels of depressive symptoms ( p = 0.028 for men, p = 0.002 for women) and fewer chronic conditions ( p = 0.002 for men, p < 0.001 for women). Notably, women in the "poor sleep quality" group exhibited higher proportions of low habitual sleep efficiency (women 35.9% vs men 29.8%) and frequent use of sleeping medications (women 23.2% vs men 9.9%) than men. Good sleep quality was associated with better resilience in both men (mean BRS score: good sleep quality = 25.1 [SD: 4.3] vs poor sleep quality = 23.4 [SD: 4.7], p = 0.004) and women (mean BRS score: good sleep quality = 24.3 [SD: 5.1] vs poor sleep quality = 22.3 [SD: 5.4], p < 0.001). After adjusting for depressive symptoms and chronic conditions, this association remained significant for men ( p = 0.022) and women ( p = 0.001). In addition, greater depressive symptoms were associated with poorer resilience in both sexes ( p < 0.001). No significant associations were noted between sleep quality or resilience and the selected biomarkers.

CONCLUSION

This study highlights the association between sleep quality and resilience in older adults. Good sleep quality is related to better resilience, but greater depressive symptoms are also linked to poorer resilience in both sexes. Nevertheless, the low habitual sleep efficiency and frequent use of sleeping medications in women but not men with poor sleep quality highlight the need to explore sex-specific approaches to address the interplay of sleep quality, resilience, and other factors (such as depressive symptoms) in healthy aging.

Effects of a cannabidiol/terpene formulation on sleep in individuals with insomnia: a double-blind, placebo-controlled, randomized, crossover study

STUDY OBJECTIVES

Cannabidiol (CBD) is increasingly used as a health supplement, though few clinical studies have demonstrated benefits. The primary objective of this study was to evaluate the effects of an oral CBD-terpene formulation on sleep physiology in individuals with insomnia.

METHODS

In this double-blind, placebo-controlled, randomized clinical trial, 125 individuals with insomnia received an oral administration of CBD (300 mg) and terpenes (1 mg each of linalool, myrcene, phytol, limonene, α-terpinene, α-terpineol, α-pinene, and β-caryophyllene) for ≥ 4 days/wk over 4 weeks using a crossover design. The study medication was devoid of Δ9-tetrahydrocannabinol. The primary outcome measure was the percentage of time participants spent in the combination of slow-wave sleep (SWS) and rapid eye movement (REM) sleep stages, as measured by a wrist-worn sleep-tracking device.

RESULTS

This CBD-terpene regimen marginally increased the mean nightly percentage of time participants spent in SWS + REM sleep compared to the placebo (mean [standard error], 1.3% [0.60%]; 95% confidence interval, 0.1-2.5%; P = .03). More robust increases were observed in participants with low baseline SWS + REM sleep, as well as in day sleepers. For select participants, the increase in SWS + REM sleep averaged as much as 48 minutes/night over a 4-week treatment period. This treatment had no effect on total sleep time, resting heart rate, or heart rate variability, and no adverse events were reported.

CONCLUSIONS

Select CBD-terpene ratios may increase SWS + REM sleep in some individuals with insomnia and may have the potential to provide a safe and efficacious alternative to over-the-counter sleep aids and commonly prescribed sleep medications.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Evaluation of an Oral Cannabidiol (CBD)-Terpene Formulation on Sleep Physiology in Participants With Insomnia; URL: https://clinicaltrials.gov/study/NCT05233761; Identifier: NCT05233761.

CITATION

Wang M, Faust M, Abbott S, et al. Effects of a cannabidiol/terpene formulation on sleep in individuals with insomnia: a double-blind, placebo-controlled, randomized, crossover study. J Clin Sleep Med. 2025;21(1):69-80.

Acoustic Stimulation to Improve Slow-Wave Sleep in Alzheimer's Disease: A Multiple Night At-Home Intervention

OBJECTIVES

To investigate the efficacy of closed-loop acoustic stimulation (CLAS) during slow-wave sleep (SWS) to enhance slow-wave activity (SWA) and SWS in patients with Alzheimer's disease (AD) across multiple nights and to explore associations between stimulation, participant characteristics, and individuals' SWS response.

DESIGN

A 2-week, open-label at-home intervention study utilizing the DREEM2 headband to record sleep data and administer CLAS during SWS.

SETTING AND PARTICIPANTS

Fifteen older patients with AD (6 women, mean age: 76.27 [SD = 6.06], mean MOCA-score: 16.07 [SD = 6.94]), living at home with their partner, completed the trial.

INTERVENTION

Patients first wore the device for two baseline nights, followed by 14 nights during which the device was programmed to randomly either deliver acoustic stimulations of 50 ms pink noise (± 40 dB) targeted to the slow-wave up-phase during SWS or only mark the wave (sham).

RESULTS

On a group level, stimulation significantly enhanced SWA and SWS with consistent SWS enhancement throughout the intervention. However, substantial variability existed in individual responses to stimulation. Individuals received more stimulations on nights with increased SWS compared to baseline than on nights with no change or a decrease. In individuals, having lower baseline SWS correlated with receiving fewer stimulations on average during the intervention.

CONCLUSION

CLAS during SWS is a promising nonpharmacological method to enhance SWA and SWS in AD. However, patients with lower baseline SWS received fewer stimulations during the intervention, possibly resulting in less SWS enhancement. Individual variability in response to stimulation underscores the need to address personalized stimulation parameters in future research and therapy development.

EEG brain networks modulation during sleep onset: the effects of aging

The aim of the present study is to investigate differences in brain networks modulation during the pre- and post-sleep onset period, both within and between two groups of young and older individuals. Thirty-six healthy elderly and 40 young subjects participated. EEG signals were recorded during pre- and post-sleep onset periods and functional connectivity analysis, specifically focusing on the small world (SW) index, applied to EEG data (i.e., frequency bands) was examined. Significant differences in SW values were found between the pre-sleep and post-sleep onset phases in both young and older groups, with a reduction in the SW index in the theta band common to both groups. Additionally, an increase in the SW index in the beta band was exclusive to the elderly group during the post-sleep onset period, while an increase in the sigma band was exclusive to the young group. Furthermore, differences between the young and elderly groups were found during both phases, including a decrease in the SW index within the delta band, an increment in the sigma and beta bands in the elderly compared to the young group during the pre-sleep onset period, and a notable absence of sigma band modulation in the elderly group during the post-sleep onset condition. These findings provide insights into age-related changes in sleep-related brain network dynamics and their potential impact on sleep quality and cognitive functions, prompting interventions aimed at supporting healthy aging and addressing age-related cognitive decline.

Sleep Disturbance in People with Anxiety or Depressive Disorders over 30 Years, and the Influence of Personality Disorder

OBJECTIVES

Sleep disturbance is commonly reported by people with anxiety, depressive, and personality disorders, but longitudinal studies exploring the interplay of the three with disturbed sleep have not previously been described.

METHODS

In this study, sleep disturbance was examined among 89 patients initially presenting with anxiety or depressive disorders who provided follow-up at 12- and 30-year time points in the Nottingham Study of Neurotic Disorder. Multilevel models were used to identify factors most predictive of changes in sleep quality over time.

RESULTS

There were strong associations between poor sleep and contemporaneous severity of personality disorder and the presence of other mental disorders at 12 and 30 years follow-up, but not with disorder presence at other time points. Improvements in personality disorder were associated with improvements in sleep between time points and attenuated the positive unadjusted effects of recovery from anxiety or depressive disorders to non-significance. Relapse into further episodes of mental disorder predicted poorer sleep, whereas worsening personality disorder was not predictive of significant changes when adjusting for other factors.

CONCLUSIONS

This study demonstrates the complex interplay between anxiety, depressive, and personality disorders and sleep disturbance over a long follow-up period. Future research might look to examine the relationship between personality disorder and disturbed sleep with interventional studies and by integrating personality trait research.

Types of Insomnia Mediate the Bidirectional Relation Between Anxiety and Depressive Symptoms Longitudinally in Older Adults

The current study examined onset and maintenance insomnia as mediators of the bidirectional relation between anxiety and depressive symptoms over a three-year period. The sample included 3,415 US community-dwelling Medicare beneficiaries aged 66-103. Participants completed measures of types of insomnia, anxiety symptoms, and depressive symptoms at four time points. Analyses included two double mediation models adjusted for baseline depressive or anxiety symptoms, chronic health problem burden, use of sleep medications, age, and sex. Both covariate-adjusted models showed significant direct relations between anxiety and depressive symptoms, and these relations were modestly partially mediated by onset and maintenance insomnia. In older adults, onset and maintenance insomnia are distinct outcomes of both anxiety and depressive symptoms and also predictors of each symptom cluster. Further research testing these models is warranted and, if supported, may support prevention and treatment studies focused on primary and secondary prevention of these problems in older adults.

Multi-night acoustic stimulation is associated with better sleep, amyloid dynamics, and memory in older adults with cognitive impairment

Sleep is a potential early, modifiable risk factor for cognitive decline and dementia. Impaired slow wave sleep (SWS) is pronounced in individuals with cognitive impairment (CI). Cognitive decline and impairments of SWS are bi-directionally linked in a vicious cycle. SWS can be enhanced non-invasively using phase-locked acoustic stimulation (PLAS), potentially breaking this vicious cycle. Eighteen healthy older adults (HC, agemean±sd, 68.3 ± 5.1) and 16 older adults (agemean±sd, 71.9 ± 3.9) with CI (Montreal Cognitive Assessment ≤ 25) underwent one baseline (sham-PLAS) night and three consecutive stimulation nights (real-PLAS). EEG responses and blood-plasma amyloid beta Aβ42/Aβ40 ratio were measured pre- and post-intervention, as was episodic memory. The latter was again evaluated 1 week and 3 months after the intervention. In both groups, PLAS induced a significant electrophysiological response in both voltage- and time-frequency analyses, and memory performance improved in association with the magnitude of this response. In the CI group, both electrophysiological and associated memory effects were delayed compared to the healthy group. After 3 intervention nights, electrophysiological response to PLAS was no longer different between CI and HC groups. Only in the CI sample, stronger electrophysiological responses were significantly associated with improving post-intervention Aβ42/Aβ40 ratios. PLAS seems to improve SWS electrophysiology, memory, and amyloid dynamics in older adults with CI. However, effects on memory require more time to unfold compared to healthy older adults. This indicates that PLAS may become a potential tool to ameliorate cognitive decline, but longer interventions are necessary to compensate for declining brain integrity. This study was pre-registered (clinicaltrials.gov: NCT04277104).

Impact of coffee intake on human aging: Epidemiology and cellular mechanisms

The conception of coffee consumption has undergone a profound modification, evolving from a noxious habit into a safe lifestyle actually preserving human health. The last 20 years also provided strikingly consistent epidemiological evidence showing that the regular consumption of moderate doses of coffee attenuates all-cause mortality, an effect observed in over 50 studies in different geographic regions and different ethnicities. Coffee intake attenuates the major causes of mortality, dampening cardiovascular-, cerebrovascular-, cancer- and respiratory diseases-associated mortality, as well as some of the major causes of functional deterioration in the elderly such as loss of memory, depression and frailty. The amplitude of the benefit seems discrete (17 % reduction) but nonetheless corresponds to an average increase in healthspan of 1.8 years of lifetime. This review explores evidence from studies in humans and human tissues supporting an ability of coffee and of its main components (caffeine and chlorogenic acids) to preserve the main biological mechanisms responsible for the aging process, namely genomic instability, macromolecular damage, metabolic and proteostatic impairments with particularly robust effects on the control of stress adaptation and inflammation and unclear effects on stem cells and regeneration. Further studies are required to detail these mechanistic benefits in aged individuals, which may offer new insights into understanding of the biology of aging and the development of new senostatic strategies. Additionally, the safety of this lifestyle factor in the elderly prompts a renewed attention to recommending the maintenance of coffee consumption throughout life as a healthy lifestyle and to further exploring who gets the greater benefit with what schedules of which particular types and doses of coffee.

Short-term exercise counteracts accelerated ageing impacts on physical performance and liver health in mice

Senescence impairs liver physiology, mitochondrial function and circadian regulation, resulting in systemic metabolic dysregulation. Given the limited research on the effects of combined exercise on an ageing liver, this study aimed to evaluate its impact on liver metabolism, circadian rhythms and mitochondrial function in senescence-accelerated mouse-prone 8 (SAMP8) and senescence-accelerated mouse-resistant 1 (SAMR1) mice. Histological, reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunoblotting analyses were conducted, supplemented by transcriptomic data sets and AML12 hepatocyte studies. Sedentary SAMP8 mice exhibited decreased muscle strength, reduced mitochondrial complex I levels and increased lipid droplet accumulation. In contrast, combined exercise mitigated muscle strength loss, upregulated proteins involved in mitochondrial complexes (CIII, CIV, CV) and increased Bmal1 messenger RNA (mRNA) expression in the liver. These molecular adaptations are associated with healthier liver phenotypes and may influence metabolic function and cellular longevity. Notably, elevated lipid content in aged mice was reduced post-exercise, indicating liver benefits even after a relatively short intervention. The combined exercise regimen did not improve aerobic capacity, likely due to the low volume and brief duration of running. Moreover, no significant effects were observed in SAMR1 mice, possibly because the training intensity was insufficient for younger, healthier animals. These findings underscore the potential of combined strength and endurance exercise to attenuate age-related liver dysfunction, particularly in ageing populations.

Intersections of Modifiable Risks: Loneliness is Associated with Poor Subjective Sleep Quality in Older Women at Risk for Alzheimer's Disease

We examined the relationship between subjective and objective sleep outcomes and loneliness in older women at risk for Alzheimer's disease (AD). Our sample consisted of 39 participants (aged 65+) with mild cognitive deficits who completed the UCLA Loneliness Scale, the Pittsburgh Sleep Quality Index (PSQI), and an at home sleep test, to determine presence of obstructive sleep apnea. Based on sleep quality scores, individuals categorized as "poor sleepers" had significantly higher loneliness scores than "good sleepers." However, total loneliness scores did not significantly differ between groups with or without sleep apnea. We found that higher loneliness was significantly associated to lower habitual sleep efficiency and sleep duration and was also influenced by use of sleep medication. Our findings suggest that increased loneliness relates to worse subjective sleep quality, but not to sleep apnea. These findings suggest that combined interventions targeting loneliness and sleep quality may be important for older women.

Sleep Deficiency in the Elderly

With aging, there are normative changes to sleep physiology and circadian rhythmicity that may predispose older adults to sleep deficiency, whereas many health-related and psychosocial/behavioral factors may precipitate sleep deficiency. In this article, we describe age-related changes to sleep and describe how the health-related and psychosocial/behavioral factors typical of aging may converge in older adults to increase the risk for sleep deficiency. Next, we review the consequences of sleep deficiency in older adults, focusing specifically on important age-related outcomes, including mortality, cognition, depression, and physical function. Finally, we review treatments for sleep deficiency, highlighting safe and effective nonpharmacologic interventions.

Association of sleep quality with physical and psychological health indicators in overweight and obese rural Indians

Objective

To measure the association of sleep quality with physical (i.e., grip strength, functional mobility, balance) and psychological (depression, anxiety) health indicators in an overweight/obese population.

Methods

Baseline data of 2337 participants (1382 overweight/obese and 955 normal weight) from an aging cohort in rural southern India (CBR-SANSCOG) was analyzed retrospectively. Assessment tools included the Pittsburgh Sleep Quality Index (PSQI) for sleep quality, dynamometry for Hand Grip Strength (HGS), Timed Up-and-Go (TUG) for functional mobility, Chair Stand Test (CST) for lower limb strength, Geriatric Depression scale (GDS-30) for depressive symptoms and Generalized Anxiety Disorder scale (GAD-7) for anxiety symptoms. Linear regression models, adjusted for known confounders, were used to examine the association of sleep quality with the health parameters in overweight/obese and normal-weight groups.

Results

In the fully adjusted model, higher global PSQI score was associated with higher TUG time (β = 0.06, 95 % CI: 0.004,0.12), higher scores on GDS (β = 1.08, 95 % CI: 0.96,1.20) and GAD (β = 0.71, 95 % CI: 0.62,0.79), and lower scores on CST (β = -0.12, 95 % CI: -0.19,-0.06) in overweight/obese individuals. The sleep disturbance sub-component of PSQI was associated with most of the physical (TUG, CST) and psychological (GDS and GAD) health indicators. Sleep duration and use of sleep medication showed no significant association with any of the health indicators.

Conclusion

The concurrent presence of poor sleep quality and overweight/obesity could worsen physical and psychological health in middle-aged and older adults. We highlight the importance of early detection and timely management of sleep problems in this population to reduce physical and psychological morbidities.

Sleep quality of vulnerable elderly people: associated factors

OBJECTIVE

To identify factors associated with poor sleep quality in elderly dependent individuals in social vulnerability.

METHOD

Cross-sectional study with 59 elderly dependent individuals assisted by Family Health Units in São Carlos/SP. The following tools were used: Katz Index, Lawton and Brody Scale, Pittsburgh Sleep Quality Index, Addenbrooke's Cognitive Examination Revised, Fried's Frailty Phenotype, Geriatric Depression Scale (15 items), Perceived Stress Scale, Family APGAR, Social Support Scale from the Medical Outcomes Study, and World Health Organization Quality of Life, abbreviated and "old" versions.

RESULTS

The majority of participants were women (52.5%), aged 60-74 years (71.1%), and had poor sleep quality (76.2%). Stress (OR=1.12; 95%CI=1.02-1.22) and polypharmacy (OR=7.39; 95%CI=1.22-44.73) increased the chances of poor sleep quality, while physical activity decreased these chances (OR=0.15; 95%CI=0.02-0.79).

CONCLUSION

Stress and polypharmacy are associated with poor sleep quality in elderly dependent individuals.

Association Between Objective Sleep and Clinical Outcomes in Older Adults With Low Back Pain Receiving Physical Therapy Care: A Secondary Analysis of a Responsiveness Study

BACKGROUND/OBJECTIVES

Sleep seems to be associated with worse low back pain (LBP) outcomes in older adults; however, studies investigating the association of objective sleep with future changes in LBP outcomes are lacking. The objectives of this study are as follows: (a) to investigate the association between objectively measured sleep with changes in clinical outcomes in older adults with LBP receiving physical therapy care and (b) to examine the cross-sectional association between sleep and pain catastrophizing.

METHODS

This was a prospective cohort study. We recruited older adults (≥60 years old) with chronic LBP undergoing physical therapy treatment. At baseline, we assessed participants' sleep (actigraphy for 10-14 days), pain intensity, disability, pain catastrophizing, and covariates. After 8 weeks, we reassessed pain intensity, disability, and self-perceived recovery. We ran linear regression models and Spearman coefficient tests.

RESULTS

Fifty-eight participants were included, and 51 completed follow-up assessments (60.8% women; mean age 70.1 ± 5.6 years). We found no associations between sleep quantity and efficiency with changes in pain intensity, disability, and self-perceived recovery after 8 weeks of physical therapy care. We found a correlation between sleep fragmentation and pain catastrophizing (r = .30; 95% confidence interval: [.03, .54]).

CONCLUSION

Objective sleep quantity and efficiency may not be associated with changes in LBP outcomes after physical therapy care in older adults. Among the sleep domains evaluated, sleep fragmentation may be the sleep domain with the strongest association with pain catastrophizing. Significance/Implications: Objectively measured sleep might not be a prognostic factor for LBP improvement in older adults. Future studies should explore the association between sleep fragmentation and pain catastrophizing.

Structural and social determinants of health: The multi-ethnic study of atherosclerosis

BACKGROUND

Researchers have increasingly recognized the importance of structural and social determinants of health (SSDOH) as key drivers of a multitude of diseases and health outcomes. The Multi-Ethnic Study of Atherosclerosis (MESA) is an ongoing, longitudinal cohort study of subclinical cardiovascular disease (CVD) that has followed geographically and racially/ethnically diverse participants starting in 2000. Since its inception, MESA has incorporated numerous SSDOH assessments and instruments to study in relation to CVD and aging outcomes. In this paper, we describe the SSDOH data available in MESA, systematically review published papers using MESA that were focused on SSDOH and provide a roadmap for future SSDOH-related studies.

METHODS AND FINDINGS

The study team reviewed all published papers using MESA data (n = 2,125) through January 23, 2023. Two individuals systematically reviewed titles, abstracts, and full text to determine the final number of papers (n = 431) that focused on at least one SSDOH variable as an exposure, outcome, or stratifying/effect modifier variable of main interest (discrepancies resolved by a third individual). Fifty-seven percent of the papers focused on racialized/ethnic groups or other macrosocial/structural factors (e.g., segregation), 16% focused on individual-level inequalities (e.g. income), 14% focused on the built environment (e.g., walking destinations), 10% focused on social context (e.g., neighborhood socioeconomic status), 34% focused on stressors (e.g., discrimination, air pollution), and 4% focused on social support/integration (e.g., social participation). Forty-seven (11%) of the papers combined MESA with other cohorts for cross-cohort comparisons and replication/validation (e.g., validating algorithms).

CONCLUSIONS

Overall, MESA has made significant contributions to the field and the published literature, with 20% of its published papers focused on SSDOH. Future SSDOH studies using MESA would benefit by using recently added instruments/data (e.g., early life educational quality), linking SSDOH to biomarkers to determine underlying causal mechanisms linking SSDOH to CVD and aging outcomes, and by focusing on intersectionality, understudied SSDOH (i.e., social support, social context), and understudied outcomes in relation to SSDOH (i.e., sleep, respiratory health, cognition/dementia).

Roles of social support and strain in predicting older adults' sleep disturbances

Sleep disturbances impact the well-being of older adults, but there has been limited research on their longitudinal patterns and how they are affected by the quality of social relationships. This study explored longitudinal sleep disturbance patterns and examined the influence of social support and social strain on sleep disturbances in older adults using data from the Health and Retirement Study (HRS) spanning from 2010 to 2018. Group-based trajectory modeling identified distinct trajectory groups. Multinomial logistic regression and a fixed effects model investigated the relationship between sleep disturbances, social support, social strain, and sociodemographic factors. Three sleep disturbance trajectories were identified: high sleep disturbances, moderate sleep disturbances, and low sleep disturbances. Multinomial logistic regression showed that higher social support decreased the likelihood of classification in the high and moderate sleep disturbance groups. Conversely, higher social strain scores increased the likelihood of belonging to the high and moderate sleep disturbance groups. The fixed effects model confirmed the role of social support in predicting sleep disturbances over time, but social strain was not a significant predictor. These findings suggest the need for tailored interventions addressing social support to reduce sleep disturbances in this population.

Sleep disorders and risk of alzheimer's disease: A two-way road

Substantial sleep impairment in patients with Alzheimer's disease (AD) is one of the emerging points for continued efforts to better understand the disease. Individuals without cognitive decline, an important marker of the clinical phase of AD, may show early alterations in the sleep-wake cycle. The objective of this critical narrative review is to explore the bidirectional pathophysiological correlation between sleep disturbances and Alzheimer's Disease. Specifically, it examines how the disruption of sleep homeostasis in individuals without dementia could contribute to the pathogenesis of AD, and conversely, how neurodegeneration in individuals with Alzheimer's Disease might lead to dysregulation of the sleep-wake cycle. Recent scientific results indicate that sleep disturbances, particularly those related to impaired glymphatic clearance, may act as an important mechanism associated with the genesis of Alzheimer's Disease. Additionally, amyloid deposition and tau protein hyperphosphorylation, along with astrocytic hyperactivation, appear to trigger changes in neurotransmission dynamics in areas related to sleep, which may explain the onset of sleep disturbances in individuals with AD. Disruption of sleep homeostasis appears to be a modifiable risk factor in Alzheimer's disease. Whenever possible, the use of non-pharmacological strategies becomes important in this context. From a different perspective, additional research is needed to understand and treat the dysfunction of the sleep-wake cycle in individuals already affected by AD. Early recognition and correction of sleep disturbances in this population could potentially mitigate the progression of dementia and improve the quality of life for those with AD.

Self-reported physical activity and sleep quality is associated with working memory function in middle-aged and older adults during the COVID-19 pandemic

While previous work has shown a positive relationship between cognitive performance and lifestyle factors in younger adults, evidence for this relationship among middle-aged and older adults has been mixed. The current study aimed to further test the relationship among physical activity, sleep quality, and memory performance in middle-aged and older adults, and to test whether this relationship holds up during the COVID-19 pandemic. Our results showed that physical activity was associated with better sleep quality and better working memory performance, and better sleep quality was associated with better working memory and self-perceptions of everyday memory abilities. Additionally, we found that the effects of physical activity on working memory were partially mediated by sleep quality. While these effects were small and only correlational in nature, they lend further support to the notion that sleep quality and physical activity are beneficial to memory later in life, even during a global pandemic.

The effect of eye mask on sleep quality and pain in patients undergoing coronary artery bypass graft surgery: A double-blind randomized controlled trial

BACKGROUND

Pain is one of the common postoperative issues that impair recovery and quality of life in patients undergoing coronary artery bypass graft (CABG) surgery. It leads to prolonged recovery and sleep disturbances in patients.

AIM

This study was conducted to examine the effect of eye mask use on sleep quality and pain in patients undergoing CABG surgery.

STUDY DESIGN

A double-blind randomized trial design was employed. The study included 60 patients undergoing CABG surgery. They were divided into intervention and control groups through block randomization. Data were collected using a 'Demographic Characteristics Form', the 'Richards-Campbell Sleep Questionnaire (RCSQ)' and a 'Visual Analogue Scale' (VAS) through face-to-face interviews. While patients in the control group received standard care throughout the night, patients in the intervention group received standard care and used eye mask. All patients were followed up for three nights. The CONSORT was used to report the study.

RESULTS

The main outcome of the study, the RCSQ score, was higher in the intervention group at baseline. The intervention group had higher RCSQ scores than the control group at time 1 and time 2. There were no differences between the groups in the secondary outcome, pain levels. The control group had higher pain scores at time 1 and time 2 than the intervention group.

CONCLUSION

The use of an eye mask after CABG surgery is an effective, safe and simple nursing intervention to improve sleep quality and control pain.

RELEVANCE TO CLINICAL PRACTICE

Because the use of an eye mask is an independent and unique nursing intervention, nurses should be supported and allowed to practise it.

[Sleep and sleep disorders in old age]

The increasing interruptions of nocturnal sleep with aging must be distinguished from actual sleep disorders. Morbidity and medication have an impact on sleep. The relationship between sleep and morbidity is mutual. Disturbed sleep modifies many clinical symptoms and diseases affect sleep and the ability to sleep. Geriatric syndromes such as falls, depression and dementia are modified by sleep disorders. Geriatric syndromes can be favorably influenced by the treatment of sleep disorders. Adequate diagnostics are important prerequisites. Coincidences of different sleep disorders are frequent. The medical history of patients and a sleep diary form the basis of the diagnostics. Sleep medicine provides further technical examination procedures. Older people should be examined in a sleep laboratory if the results have consequences that are accepted by the patient. This should be clarified in advance.

Symptom subtype progression in obstructive sleep apnea over 5 years

STUDY OBJECTIVES

There is limited knowledge regarding the progression or consistency of symptoms in obstructive sleep apnea (OSA) over time. Our objective was to examine the changes in symptom subtypes and identify predictors over a span of 5 years.

METHODS

Data of 2,643 participants of the Sleep Heart Health Study with complete baseline and 5-year follow-up visits were analyzed. Latent class analysis on 14 symptoms at baseline and follow-up determined symptom subtypes. Individuals without OSA (apnea-hypopnea index < 5) were incorporated as a known class at each time point. Multinomial logistic regression assessed the effect of age, sex, body mass index, and apnea-hypopnea index on specific class transitions.

RESULTS

The sample consisted of 1,408 females (53.8%) and mean (standard deviation) age 62.4 (10.5) years. We identified 4 OSA symptom subtypes at both baseline and follow-up visits: minimally symptomatic, disturbed sleep, moderately sleepy, and excessively sleepy. Nearly half (44.2%) of the sample transitioned to a different subtype; transitions to moderately sleepy were the most common (77% of all transitions). A 5-year older age was associated with a 50% increase in odds to transit from excessively sleepy to moderately sleepy (odds ratio [95% confidence interval]: 1.52 [1.17, 1.97]). Females had 1.97 times higher odds (95% confidence interval: 1.21, 3.18) to transition from moderately sleepy to minimal symptoms. A 5-unit increase in body mass index was associated with 2.39 greater odds (95% confidence interval: 1.30, 4.40) to transition from minimal symptoms to excessively sleepy. Changes in apnea-hypopnea index did not significantly predict any transitions.

CONCLUSIONS

The symptoms of OSA may fluctuate or remain stable over time. Knowledge of symptom progression in OSA may support clinicians with treatment decisions.

CITATION

Morris JL, Scott PW, Magalang U, et al. Symptom subtype progression in obstructive sleep apnea over 5 years. J Clin Sleep Med. 2024;20(11):1773-1783.

Associations between Recession Hardships and Subjective and Objective Sleep Measures in the Midlife in the United States Study: Race and Gender Differences

Objectives

This study investigates the associations of retrospective reports of Recession hardships with 10-year changes in subjective and objective indicators of sleep, and whether these associations differ by race and gender.

Methods

501 adults (14.57% Black; 54.49% female) from the Midlife in the United States (MIDUS) study reported on the subjective Pittsburgh Sleep Quality Index (PSQI) across two waves (pre-Recession, collected 2004-2009; post-Recession, collected 2017-2022), as well as Recession hardships since 2008. A sub-sample of 201 adults (25.37% Black; 58.21% female) provided objective actigraphy-measured sleep data (total sleep time, sleep onset latency, sleep efficiency) across the two waves.

Results

Descriptive analyses revealed Black participants had higher average Recession hardships, poorer post-Recession PSQI scores, and poorer post-Recession actigraphy sleep quantity and quality compared to white participants. Females had higher average Recession hardships compared to males; and reported poorer post-Recession PSQI, but had better objective post-Recession sleep quantity and quality compared to males. Regression models showed Recession hardships (across overall events, and sub-domains of financial and housing hardships) were associated with poorer PSQI and actigraphy-measured sleep efficiency following the Recession, adjusting for sociodemographic covariates, corresponding pre-Recession sleep variables, and pre-Recession chronic conditions. There was no evidence for significant moderation by race on sleep outcomes. However, gender moderation indicated associations between housing hardships and poorer actigraphy-measured sleep efficiency were more apparent for females than for males.

Conclusions

Findings indicate that Recession hardships (particularly in financial and housing domains) may be manifested in poor sleep. Racial and gender groups may have differential exposure and sleep-related reactivity to Recession hardships.

Insomnia symptoms and increased risk of all-cause mortality by age and sex

STUDY OBJECTIVES

Prior research suggests that insomnia may increase the risk of death. However, the potential influence of age and sex is unclear. This study aimed to investigate the association of insomnia symptoms with all-cause mortality by age and sex.

METHODS

This prospective cohort was drawn from the Health and Retirement Study, a survey of Americans older than 50 years and their spouses of any age from 2002-2018. Insomnia symptom scores were based on difficulties initiating sleep, difficulty maintaining sleep, waking up too early, and nonrestorative sleep. Cox proportional-hazards regression models were employed to investigate the association between insomnia symptoms and all-cause mortality stratified by age and sex.

RESULTS

A total of 33,004 participants were included with a mean age of 61.7 years and 56.8% females. Over a mean follow-up of 8.4 years, 8,935 (27.1%) deaths were recorded. After adjusting for confounding, males with insomnia symptom scores ranging from 5-8 had a 71% increased risk of death (hazard ratio = 1.71; 95% confidence interval: 1.27, 2.30) compared with their counterparts without insomnia symptoms. Similarly, males aged ≥ 60 years and females aged < 60 years with insomnia symptoms ranging from 5-8 had an increased risk of death compared with their counterparts without insomnia symptoms (hazard ratio = 1.15; 95% confidence interval: 1.02, 1.31 and hazard ratio = 1.38; 95% confidence interval: 1.00, 1.90, respectively). However, there was no increased risk of death for females aged ≥ 60 years (hazard ratio = 0.94; 95% confidence interval: 0.84, 1.06).

CONCLUSIONS

These findings suggest that insomnia symptoms may serve as predictors of low life expectancy.

CITATION

Sawadogo W, Adera T. Insomnia symptoms and increased risk of all-cause mortality by age and sex. J Clin Sleep Med. 2024;20(10):1585-1593.

Associations between sleep duration trajectories and risk of cardio-metabolic disease among middle-aged and older Chinese adults

BACKGROUND

The association of a single time-point measure of sleep duration with cardio-metabolic disease has been extensively studied, but few studies have focused on the impact of sleep duration trajectory. This study aims to model the sleep duration trajectory as predictors for the subsequent development of cardio-metabolic disease.

METHODS

This study recruited a notably large population (n = 9883) of subjects aged at least 45 years from the China Health and Retirement Longitudinal Study (CHARLS), who participated in sequential surveys conducted in 2011, 2013, 2015, and 2018. Sleep duration trajectories were plotted using data of night sleep duration recorded at intervals from 2011 to 2015 by latent class trajectory model. The onset of cardio-metabolic diseases from 2015 to 2018 were confirmed and then the risk of different sleep duration trajectories on incident cardio-metabolic disease was examined using cox proportional hazards regression model.

RESULTS

We identified four sleep duration trajectories. Compared to the normal-stable trajectory, the short-stable trajectory was significantly associated with higher risk of incident stroke (hazard ratio [HR], 1.32; 95 % confidence interval [CI], 1.02 to 1.70), dyslipidemia (HR, 1.22; 95%CI, 1.01 to 1.49), and diabetes (HR, 1.42; 95%CI, 1.13 to 1.78) within three years of follow-up, and the short-increasing trajectory predicted a higher risk of incident stroke (HR, 2.38; 95%CI, 1.25 to 4.55).

CONCLUSIONS

Short sleep trajectory could increase the risk of incident stroke, dyslipidemia, and diabetes, and an increasing sleep trajectory was associated with increased risk of incident stroke among middle-aged and older Chinese adults.

The effects of partial sleep restriction and subsequent caffeine ingestion on neurovascular coupling

Habitual poor sleep is associated with cerebrovascular disease. Acute sleep deprivation alters the ability to match brain blood flow to metabolism (neurovascular coupling [NVC]) but it is not known how partial sleep restriction affects NVC. When rested, caffeine disrupts NVC, but its effects in the sleep-restricted state are unknown. The purpose of this study was therefore to investigate the effects of partial sleep restriction and subsequent caffeine ingestion on NVC. A total of 17 adults (mean [standard deviation] age 27 [5] years, nine females) completed three separate overnight conditions with morning supplementation: habitual sleep plus placebo (Norm_Pl), habitual sleep plus caffeine (Norm_Caf), and partial (50% habitual sleep) restriction plus caffeine (PSR_Caf). NVC responses were quantified as blood velocity through the posterior (PCAv) and middle (MCAv) cerebral arteries using transcranial Doppler ultrasound during a visual search task and cognitive function tests, respectively. NVC was assessed the evening before and twice the morning after each sleep condition-before and 1-h after caffeine ingestion. NVC responses as a percentage increase in PCAv and MCAv from resting baseline were not different at any timepoint, across all conditions (p > 0.053). MCAv at baseline, and PCAv at baseline, peak, and total area under the curve were lower 1-h after caffeine in both Norm_Caf and PSR_Caf as compared to Norm_Pl (p < 0.05), with no difference between Norm_Caf and PSR_Caf (p > 0.14). In conclusion, NVC was unaltered after 50% sleep loss, and caffeine did not modify the magnitude of the response in the rested or sleep-deprived state. Future research should explore how habitual poor sleep affects cerebrovascular function.

Sleep as a Predictor of Health-Related Quality of Life among Economically Disadvantaged Black Older Adults

Objectives

Sleep disturbances may partially account for the health-related quality of life (HRQoL) disparities experienced by Black older adults when compared to non-Hispanic White (NHW) adults. The present study examined the role of self-reported sleep duration and the belief that one is not getting enough sleep on physical and mental HRQoL among Black older adults.

Design

Participants were 281 community-dwelling, economically disadvantaged Black older adults between 60 and 97 years of age (Mean=69.01, SD=6.97) who lived in a large city in the Southeastern United States. The present study uses baseline data from a larger intervention study aimed at promoting social connection and food security among older adults. For this study (and as part of the larger intervention), participants completed an assessment battery that included (1) a demographic data and health questionnaire that included self-reported sleep duration and a belief that one is not getting enough sleep questions; (2) the CDC (Centers for Disease Control and Prevention) Health-Related Quality of Life-14 Healthy Days Core Module; and (3) the World Health Organization Quality of Life-Brief Form.

Results

Descriptive results show that most participants slept less than 7 hours and felt like they did not get enough sleep. Results from 2 hierarchical regressions also showed that believing one is not getting enough sleep predicts lower self-reported mental and physical HRQoL.

Conclusion

While sleep deprivation has a serious impact on quality of life for Black older adults, sleep disturbances in this population are understudied. Interventions to improve sleep duration and quality among Black older adults may help reduce disparities in quality of life between Black older adults and NHW adults.

Associations of nighttime sleep, midday napping, and physical activity with all-cause mortality in older adults: the Seniors-ENRICA cohorts

We examined associations between nighttime sleep and midday nap duration with all-cause mortality according to adherence to moderate-to-vigorous physical activity (MVPA) recommendations in older adults. We used data from 3518 and 3273 older adults recruited in the Seniors-ENRICA-1 and 2 cohorts, respectively. Nighttime sleep time was classified as short (< 7 h), middle (≥ 7 and < 8 h), and long (≥ 8 h), and midday napping as no nap, short (≤ 30 min), long (> 30 and ≤ 60 min), and very long (> 60 min). Time spent in MVPA was classified as meeting (i.e., ≥ 150 min/week) or not the MVPA recommendations. All-cause mortality was the main outcome. Analyses were performed with Cox regression and adjusted for the main confounders. Overall, compared with middle nighttime sleep, both short (HR 1.20; 95% CI 1.03-1.39) and long (HR 1.30; 95% CI 1.12-1.52) were associated with higher mortality. Among participants who did not meet MVPA recommendations, the association between short (HR 1.22; 95% CI 1.01-1.48) and long (HR 1.46; 95% CI 1.21-1.77) sleeping duration mortality remained. Short napping was associated with lower mortality (HR 0.83; 95% CI 0.71-0.96) and very long with higher mortality (HR 1.29; 95% CI 1.04-1.59), compared to those who did not nap. Among participants not meeting MVPA recommendations, only very long napping was associated with increased mortality (HR 1.32; 95% CI 1.01-1.73). No associations were identified between nighttime sleep or midday napping with mortality among participants meeting MVPA recommendations. Meeting MVPA recommendations can attenuate the risks associated with short or long sleep duration.

Sleep characteristics and self-reported sleep quality in the oldest-old: Results from a prospective longitudinal cohort study

Little is known about the correlation between subjective perception and objective measures of sleep quality in particular in the oldest-old. The aim of this study was to perform longitudinal home sleep monitoring in this age group, and to correlate results with self-reported sleep quality. This is a prospective longitudinal home sleep-monitoring study in 12 oldest-old persons (age 83-100 years, mean 93 years, 10 females) without serious sleep disorders over 1 month using a contactless piezoelectric bed sensor (EMFIT QS). Participants provided daily information about perceived sleep. Duration in bed: 264-639 min (M = 476 min, SD = 94 min); sleep duration: 239-561 min (M = 418 min, SD = 91 min); sleep efficiency: 83.9%-90.7% (M = 87.4%, SD = 5.0%); rapid eye movement sleep: 21.1%-29.0% (M = 24.9%, SD = 5.5%); deep sleep: 13.3%-19.6% (M = 16.8%, SD = 4.5%). All but one participant showed a weak (r = 0.2-0.39) or very weak (r = 0-0.19) positive or negative correlation between self-rated sleep quality and the sleep score. In conclusion, longitudinal sleep monitoring in the home of elderly people by a contactless piezoelectric sensor system is feasible and well accepted. Subjective perception of sleep quality does not correlate well with objective measures in our study. Our findings may help to develop new approaches to sleep problems in the oldest-old including home monitoring. Further studies are needed to explore the full potential of this approach.

Exploratory functional and quality of life outcomes with daily consumption of the ketone ester bis-octanoyl (R)-1,3-butanediol in healthy older adults: a randomized, parallel arm, double-blind, placebo-controlled study

Background

Ketone bodies are metabolites produced during fasting or on a ketogenic diet that have pleiotropic effects on the inflammatory and metabolic aging pathways underpinning frailty in in vivo models. Ketone esters (KEs) are compounds that induce hyperketonemia without dietary changes and that may impact physical and cognitive function in young adults. The functional effects of KEs have not been studied in older adults.

Objectives

Our long-term goal is to examine if KEs modulate aging biology mechanisms and clinical outcomes relevant to frailty in older adults. Here, we report the exploratory functional and quality-of-life outcome measures collected during a 12-week safety and tolerability study of KE (NCT05585762).

Design

Randomized, placebo-controlled, double-blinded, parallel-group, pilot trial of 12-weeks of daily KE ingestion.

Setting

The Clinical Research Unit at the Buck Institute for Research on Aging, California.

Participants

Community-dwelling older adults (≥ 65 years), independent in activities of daily living, with no unstable acute medical conditions (n = 30).

Intervention

Subjects were randomly allocated (1:1) to consume 25 g daily of either KE (bis-octanoyl (R)-1,3-butanediol) or a taste, appearance, and calorie-matched placebo (PLA) containing canola oil.

Measurements

Longitudinal change in physical function, cognitive function and quality of life were assessed as exploratory outcomes in n = 23 completers (n = 11 PLA, n = 12 KE). A composite functional outcome to describe the vigor-frailty continuum was calculated. Heart rate and activity was measured throughout the study using digital wearables.

Results

There were no statistically significant longitudinal differences between groups in exploratory functional, activity-based or quality of life outcomes.

Conclusion

Daily ingestion of 25 g of KE did not affect exploratory functional or quality-of-life end points in this pilot cohort of healthy older adults. Future work will address these endpoints as primary and secondary outcomes in a larger trial of pre-frail older adults.

Inclusion, reporting and analysis of demographic variables in chronobiology and sleep research

Many aspects of sleep and circadian physiology are sensitive to participant-level characteristics. While recent research robustly highlights the importance of considering participant-level demographic information, the extent to which this information is consistently collected, and reported in the literature, remains unclear. This article investigates study sample characteristics within the published sleep and chronobiology research over the past 40 years. 6,777 articles were identified and a random sample of 20% was included. The reporting of sample size, age, sex, gender, ethnicity, level of education, socio-economic status, and profession of the study population was scored, and any reported aggregate summary statistics for these variables were recorded. We observed a significant upward trend in the reporting and analysis of demographic variables in sleep and chronobiology research. However, we found that while > 90% of studies reported age or sex, all other variables were reported in < 25% of cases. Reporting quality was highly variable, indicating an opportunity to standardize reporting guidelines for participant-level characteristics to facilitate Meta analyses.

Actigraphic monitoring of sleep and circadian rest-activity rhythm in individuals with major depressive disorder or depressive symptoms: A meta-analysis

BACKGROUND

Disrupted sleep and rest-activity pattern are common clinical features in depressed individuals. This meta-analysis compared sleep and circadian rest-activity rhythms in people with major depressive disorder (MDD) or depressive symptoms and healthy controls.

METHODS

Eligible studies were identified in five databases up to December 2023. The search yielded 53 studies with a total of 11,115 participants, including 4000 depressed participants and 7115 healthy controls.

RESULTS

Pooled meta-analyses demonstrated that depressed individuals have significantly longer sleep latency (SMD = 0.23, 95 % CI: 0.12 to 0.33) and wake time after sleep onset (SMD = 0.37, 95 % CI: 0.22 to 0.52), lower sleep efficiency (SMD = -0.41, 95 % CI: -0.56 to -0.25), more nocturnal awakenings (SMD = 0.58, 95 % CI: 0.29 to 0.88), lower MESOR (SMD = -0.54, 95 % CI: -0.81 to -0.28), amplitude (SMD = -0.33, 95 % CI: -0.57 to -0.09), and interdaily stability (SMD = -0.17, 95 % CI: -0.28 to -0.05), less daytime (SMD = -0.79, 95 % CI: -1.08 to -0.49) and total activities (SMD = -0.89, 95 % CI: -1.28 to -0.50) when compared with healthy controls.

LIMITATIONS

Most of the included studies reported separate sleep and activity parameters instead of 24-hour rest-activity rhythms. The variabilities among actigraphy devices and the types of participants recruited also impede precise comparisons.

CONCLUSIONS

The findings emerging from this study offered a better understanding of sleep and rest-activity rhythm in individuals with MDD or depressive symptoms. Future studies could advocate for deriving objective, distinctive 24-hour rest-activity profiles contributing to the risk of depression.

PROSPERO REGISTRATION NUMBER

CRD42021259780.

Daily associations between salivary cortisol and electroencephalographic-assessed sleep: a 15-day intensive longitudinal study

STUDY OBJECTIVES

Current evidence suggests that cortisol levels are bi-directionally associated with sleep. However, the daily, naturalistic cortisol-sleep associations remain unclear, as current evidence is mostly cross-sectional. This study tested whether pre-sleep cortisol predicts sleep duration and quality, and whether these sleep parameters predict the following day's diurnal cortisol slope using a 15-day intensive longitudinal design with electroencephalographic measures and saliva sampling.

METHODS

Ninety-five young adults (Mage = 20.48 ± 1.59 years) provided saliva samples at awakening and pre-sleep over 14 consecutive days, providing 2345 samples (85% viable). The Z-Machine Insight + was used to record over 900 nights of total sleep time (TST) and sleep efficiency (SE). Multilevel models tested these data at the between- and within-person levels.

RESULTS

Higher pre-sleep cortisol predicted shorter TST (p < .001) and lower SE (p < .001) at the within-person level. Individuals with shorter average TST (p = .007) or lower average SE (p < .001) had flatter diurnal cortisol slopes, compared to those with longer average TST or higher average SE. Follow-up analyses showed that individuals with shorter average TST (vs. longer average TST) had higher pre-sleep cortisol levels (p = .01).

CONCLUSIONS

Our findings provide evidence that pre-sleep cortisol is associated with sleep duration and quality at the within-individual level. Furthermore, individuals with short or poor sleep had flatter diurnal cortisol slopes. Although the effect sizes are small, these findings show the naturalistic associations between sleep and cortisol in a relatively healthy sample. These findings suggest that sleep maintains the regulation of the stress-response system, which is protective against mental and physical disorders.

Sleep, hopelessness, and suicidal ideation: An ecological momentary assessment and actigraphy study

Recent research shows that sleep disturbances are linked to increased suicidal ideation. In the present longitudinal cohort study, we used subjective (ecological momentary assessment, EMA) and objective (actigraphy) measures to examine the effects of sleep parameters on next-day suicidal ideation. Further, we examined hopelessness as a mediator between insufficient sleep and increased suicidal ideation. Individuals with current suicidal ideation (N = 82) completed 21 days of EMA and actigraphy to estimate suicidal ideation, hopelessness and sleep parameters. Multilevel linear-mixed models were used to examine the effects of sleep parameters on next-day suicidal ideation, as well as for the mediating effect of hopelessness (in the morning) on the association between previous night's sleep and suicidal ideation levels the next day. Significant concordance existed between subjective and objective sleep measures, with moderate-to-large correlations (r = 0.44-0.58). Lower subjective sleep quality and efficiency, shorter total sleep time and increased time awake after sleep onset were significantly associated with increased next-day suicidal ideation (controlling for previous-day suicidal ideation). Actigraphy-measured sleep fragmentation was also a significant predictor of next-day ideation. Hopelessness mediated the effects of the subjective sleep parameters on suicidal ideation, but did not account for the association with sleep fragmentation. Therefore, individuals' psychological complaints (hopelessness, suicidal ideation) were better predicted by subjective sleep complaints than by objective sleep indices. Increased hopelessness following from perceived insufficient sleep appears an important explanatory factor when considering the link between sleep disturbances and suicidal ideation.

Circadian rhythm disruption and retinal dysfunction: a bidirectional link in Alzheimer's disease?

Dysfunction in circadian rhythms is a common occurrence in patients with Alzheimer's disease. A predominant function of the retina is circadian synchronization, carrying information to the brain through the retinohypothalamic tract, which projects to the suprachiasmatic nucleus. Notably, Alzheimer's disease hallmarks, including amyloid-β, are present in the retinas of Alzheimer's disease patients, followed/associated by structural and functional disturbances. However, the mechanistic link between circadian dysfunction and the pathological changes affecting the retina in Alzheimer's disease is not fully understood, although some studies point to the possibility that retinal dysfunction could be considered an early pathological process that directly modulates the circadian rhythm.

A 6-month educational program improves sleep behaviour in community-dwelling frail older adults: A randomised controlled trial

BACKGROUND

The prevalence of sleep-related issues among older adults is a significant concern, with half of the older population reporting these problems. Consequently, strategies to improve sleep are needed for this population. This study aims to assess the effects of a health educational program on sleep behaviour among pre-frail or frail older adults residing in the community and to explore possible associations with frailty.

METHODS

This randomised controlled trial (NCT05610605) included a total of 197 community-dwelling older adults with frailty/pre-frailty, divided into control (n = 88) and educational (n = 109) groups, were assessed at baseline, after the 6-month educational program (6 months), and 6 months after the intervention (12 months). The intervention comprised four group sessions and six follow-up phone calls, focusing on frailty, physical activity, dietary habits, and cognitive training. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) and wrist-worn accelerometry.

RESULTS

At 6 months, a significant time-by-group interaction was found for self-reported [β = -0.449, 95%CI (-0.844, -0.053), p = 0.026] and accelerometer-measured [β = 0.505, 95%CI (0.085, 0.926), p = 0.019] sleep efficiency, showing improved sleep efficiency in the intervention group vs. controls. A significant time-by-group interaction at 6 months was noted for sleep awakenings [β = -0.402, 95%CI (-0.825, -0.020), p = 0.047]. The educational program led to a significant decrease in awakenings, while the control group experienced an increase. The change in the number of awakenings (Rs = 0.183, p = 0.020) at 6 months was significantly associated with changes in frailty. Moreover, a significant time-by-group interaction was reported at the 12-month assessment [β = -0.449, 95%CI (-0.844, -0.053), p = 0.026] for self-reported sleep quality, indicating better results in the intervention group compared to controls.

CONCLUSION

The educational program improved sleep quality and sleep efficiency while reducing the number of awakenings per night among community-dwelling frail older adults, offering a practical approach to addressing sleep-related challenges in this demographic.

Prevalence of sleep disturbances in people with mild cognitive impairment: A systematic review and meta-analysis

This review was performed to determine sleep disturbance prevalence in individuals with mild cognitive impairment (MCI). The MEDLINE, Embase, Cochrane Library, CINAHL, PsycINFO, and Web of Science databases were systematically searched from inception to January 20, 2024. Fifty-two studies fulfilling the eligibility criteria were included. However, six of these studies were excluded from data synthesis due to poor methodological quality. The subjective sleep disturbance prevalence among all individuals with MCI was 35.8 % (95 % CI: 31.9-39.7) across 44 studies, and the objective sleep disturbance prevalence was 46.3 % (95 % CI: 36.3-56.3) across 6 studies. Five studies examined TST and WASO, while three assessed SE. Among all potential objective assessments of sleep disturbance prevalence, only TST, WASO, and SE could be meta-analyzed in MCI because of the limited number of studies available. The estimated sleep disturbance prevalence differed significantly according to measurement method, geographical region, and research design. However, the data source did not significantly influence prevalence estimates. In meta-regression analysis, publication year, participant age, percentage of females, and study quality did not predict prevalence. As subjective and objective sleep disturbances are common in people with MCI, effective intervention strategies should be developed to alleviate them.

The enigma of sleep: Implications of sleep neuroscience for the dental clinician and patient

BACKGROUND

Sleep disturbances have been shown to result in considerable morbidity and mortality. It is important for dental clinicians to understand the neuroscience behind sleep disorders.

TYPES OF STUDIES REVIEWED

The authors conducted a search of the literature published from January 1990 through March 2024 of sleep medicine-related articles, with a focus on neuroscience. The authors prioritized articles about the science of sleep as related to dental medicine.

RESULTS

The authors found a proliferation of articles related to sleep neuroscience along with its implications in dental medicine. The authors also found that the intricate neuroscientific principles of sleep medicine are being investigated robustly. The salient features of, and the differences between, central and obstructive sleep apneas have been elucidated. Sleep genes, such as CRY, PER1, PER2, and CLOCK, and their relationship to cancer and neurodegeneration are also additions to this rapidly developing science.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The dental clinician has the potential to be the first to screen patients for possible sleep disorders and make prompt referrals to the appropriate medical professionals. This can be lifesaving as well as minimize potential future morbidity for the patient.

The Interplay between Mechanoregulation and ROS in Heart Physiology, Disease, and Regeneration

Cardiovascular diseases are currently the most common cause of death in developed countries. Due to lifestyle and environmental factors, this problem is only expected to increase in the future. Reactive oxygen species (ROS) are a key player in the onset of cardiovascular diseases but also have important functions in healthy cardiac tissue. Here, the interplay between ROS generation and cardiac mechanical forces is shown, and the state of the art and a perspective on future directions are discussed. To this end, an overview of what is currently known regarding ROS and mechanosignaling at a subcellular level is first given. There the role of ROS in mechanosignaling as well as the interplay between both factors in specific organelles is emphasized. The consequences at a larger scale across the population of heart cells are then discussed. Subsequently, the roles of ROS in embryogenesis, pathogenesis, and aging are further discussed, exemplifying some aspects of mechanoregulation. Finally, different models that are currently in use are discussed to study the topics above.

The Impact of Lunch Timing on Nap Quality

PURPOSE

Previous research has established that food intake is a biological regulator of the human sleep-wake cycle. As such, the timing of eating relative to sleep may influence the quality of sleep, including daytime naps. Here, we examine whether the timing of lunch (1 h vs. 2 h interval between lunch and a napping opportunity) impacts the quality of an afternoon nap.

METHODS

Using a randomized within-subject design over two separate experimental sessions (7 days apart), participants (n = 40, mean age = 25.8 years) consumed lunch 1 h and 2 h prior to an afternoon nap opportunity. Polysomnography and subjective self-reports were used to assess sleep architecture, sleepiness levels, and nap quality.

RESULTS

Results revealed no significant differences in subjective ratings of sleep quality and sleepiness, or in sleep architecture (total sleep time, sleep efficiency, sleep onset latency, sleep stages) between the 1 h and 2-h lunch conditions.

CONCLUSIONS

All sleep measures were similar when napping followed eating by either 1 h or 2 h, suggesting that eating closer to nap onset may not negatively impact sleep architecture and quality. Future research should continue to identify conditions that improve nap quality, given the well-documented benefits of naps to reduce sleep pressure and improve human performance.

The mediating and moderating effects of psychological distress on the relationship between social media use with perceived social isolation and sleep quality of late middle-aged and older adults

OBJECTIVES

Older adults are more likely to have poor sleep quality and be socially isolated. The present study examined the potential benefits and disadvantages of social media use (SMU) with respect to sleep quality and perceived social isolation among Iranian late-middle-aged and older adults with focus a on both the mediating and moderating role of psychological distress.

METHODS

A population-based cross-sectional study was conducted among 900 older community-dwellers living in Shiraz using a structured questionnaire. Social media use was assessed by estimating the frequency of social networking site visits per week. Data concerning self-rated physical health, chronic medical and mental health conditions, perceived social isolation, sleep quality, and psychological distress were also collected. Multiple linear regression was used to identify independent variables associated with outcomes. Then, mediation and moderation models were used to examine the potential mediating and moderating effects of psychological distress and SMU on their relationships with the study variables.

RESULTS

Higher social media use was associated with better sleep quality and less perceived social isolation. Nevertheless, the relationships between SMU and participants' sleep quality and perceived social isolation were largely mediated by their level of psychological distress. Furthermore, SMU had a significant moderating effect in the relationship between the psychological distress and the levels of perceived social isolation, so that participants with higher frequency of SMU per week felt less loneliness.

CONCLUSIONS

The study findings suggest that SMU has a positive buffering effect regarding late middle-aged and older adults' mental health mainly through moderation of their perceived social isolation. The mediating role of psychological distress in research examining the relationship between SMU and older adults' mental health outcomes should be considered in future research.

The early-stage impacts of shock events on adult sleep: Lessons from the COVID-19 pandemic

The present study aims to estimate the early-stage association of the coronavirus disease 2019 (COVID-19) pandemic with sleep duration, 4 months after the initial outbreak, at a national level. Using the China Family Panel Studies in 2018 and its follow-up in 2020, 16,563 adult participants were analyzed in our study. The first wave transmissibility of the COVID-19 pandemic in mainland China was used as a quasi-natural experiment. The difference in difference method was employed to compare variations across participants interviewed before or after the pandemic and between groups from provinces with different COVID-19 severity. The study observed a decline in workday sleep duration among adults, regardless of their employment status. Specifically, working adults experienced a significant decrease in sleep duration on work days (-1.54, 95% confidence interval -2.16 to -0.92), alongside an increase on work-free days (2.41, 1.56-3.24), leading to a wider sleep discrepancy in sleep patterns (3.95, 3.31-4.59). Noteworthy, working-age adults (-2.00, -2.79 to -1.22) and males (-3.31, -4.31 to -2.30) exhibited greater sleep decreases on work days, whereas females exhibited a more pronounced disparity in sleep patterns (6.18, 4.73-7.63) between work and work-free days. The pandemic is significantly associated with prolonged changes in adults' sleep duration, including sleep decreases on work days and catch-up sleep on work-free days for working adults. To prepare for future global emergencies, the government may need to promote resilience to mitigate the pandemic's adverse impacts on the working population. Guaranteeing adequate sleep among working adults and reducing sleep debt should be prioritized in such efforts.

The training times of athletes could play a role in clinical sleep problems due to their associations with sleep difficulty scores

OBJECTIVES

Sleep is a key component of athletic recovery, yet training times could influence the sleep of athletes. The aim of the current study was to compare sleep difficulties in athletes across different training time groups (early morning, daytime, late evening, early morning plus late evening) and to investigate whether training time can predict sleep difficulties.

METHODS

Athletes from various sports who performed at a national-level (n = 273) answered the Athlete Sleep Screening Questionnaire (ASSQ) along with several other questionnaires related to demographics, exercise training, and mental health. From the ASSQ, a Sleep Difficulty Score (SDS) was calculated. Transformed SDS (tSDS) was compared across different training time categories using multiple one-way ANOVAs. A stepwise regression was then used to predict tSDS from various sleep-related factors.

RESULTS

SDSs ranged from none (31%), mild (38%), moderate (22%), and severe (9%). However, the one-way ANOVAs revealed training earlier or later vs. training daytime shifted the tSDS in a negative direction, a trend toward increased sleep difficulty. In particular, athletes training in the late evening (>20:00 or >21:00) had a significantly higher tSDS when compared to daytime training (p = .03 and p < .01, respectively). The regression model (p < .001) explained 27% of variance in the tSDS using depression score, age, training time, and chronotype score.

CONCLUSION

Among a heterogeneous sample of national-level athletes, 31% displayed moderate to severe SDSs regardless of their training time. However, when athletes trained outside daytime hours there was a tendency for the prevalence of sleep difficulties to increase.

Changes in Restless Sleep, Self-Control, and Alcohol-Related Problems with Police from Late Adolescence to Adulthood

Sleep quality is crucial for healthy adolescent brain development, which has downstream effects on self-control and involvement in risky behaviors, such as alcohol use. While previous studies have found that sleep and facets of self-control are associated with patterns of alcohol use, few have assessed whether these constructs are tied to alcohol-related problems with law enforcement during the transitional period from adolescence to adulthood. The current study uses self-report panel data from ages 16 to 27 from a population-based sample of U.S. youth (N = 956; 36.86% female). The goal of the current study is to assess the association between changes in restless sleep, impulsivity, sensation seeking, and problems with police during or shortly after consuming alcohol from adolescence to adulthood to begin to address this gap in the existing literature. Results from a multivariate latent growth curve model reveal that faster increases in restless sleep and slower declines in impulsivity are associated with slower declines in police contact. Correlated changes between restless sleep, impulsivity, and police contact are slightly greater from ages 16-21 than for ages 22-27, with males showing stronger associations. The reported results suggest that identifying developmental mechanisms between changes in poor sleep, impulsivity, and alcohol use behaviors during this life-course phase will be crucial moving forward to help divert youth away from alcohol-related contact with the police.

Longitudinal associations between biopsychosocial stress indicators and sleep in older Puerto Rican adults

OBJECTIVES

To examine the association of biopsychosocial stress indicators (perceived stress, perceived discrimination, stressful life events, and allostatic load) with sleep outcomes (sleep duration and insomnia symptoms) and to examine sex and age interactions for associations between stress and sleep in older Puerto Rican adults.

METHODS

Secondary analyses were performed with 830 participants (72% female) from wave 2 (2006-2011) of the Boston Puerto Rican Health Study (BPRHS), a prospective population-based cohort study (45-75years at baseline) and Boston Puerto Rican Osteoporosis Study (BPROS) (2007-2012), an ancillary study of the BPRHS. Recruitment occurred in randomly selected census blocks using door-to-door and community-based activities. In-home data collection visits included a baseline assessment and follow-up interviews. Questionnaires assessed perceived stress, discrimination, stressful life events, and sleep. Allostatic load indicators were measured objectively. Regression models controlled for sociodemographic, behavioral, and health factors, with interaction analyses, followed by sex- and sex-by-age-stratified analyses.

RESULTS

In the prior 2years, participants with chronic stress had 50% greater odds of reporting nonoptimal sleep duration (<7 or >9 hours). Life events trajectories were significantly related to insomnia symptoms. Men ≥65years who experienced chronic stress had greater insomnia symptoms than women, or than men with low stress or acute stress.

CONCLUSIONS

Stressful life events may affect sleep duration and insomnia symptoms among older Puerto Rican adults, particularly men 65 years and older who experienced chronic stress. Given the differences in sleep patterns experienced by older adults and their relationships with health outcomes, identifying methods to support sleep health among those with chronic stress is important.

Ageing-related modification of sleep and breathing in orexin-knockout narcoleptic mice

Narcolepsy type-1 (NT1) is a lifelong sleep disease, characterised by impairment of the orexinergic system, with a typical onset during adolescence and young adulthood. Since the wake-sleep cycle physiologically changes with ageing, this study aims to compare sleep patterns between orexin-knockout (KO) and wild type (WT) control mice at different ages. Four groups of age-matched female KO and WT mice (16 weeks of age: 8 KO-YO and 9 WT-YO mice; 87 weeks of age: 13 KO-OLD and 12 WT-OLD mice) were implanted with electrodes for discriminating wakefulness, rapid-eye-movement sleep (REMS), and non-REMS (NREMS). Mice were recorded for 48 h in their home cages and for 7 more hours into a plethysmographic chamber to characterise their sleep-breathing pattern. Regardless of orexin deficiency, OLD mice spent less time awake and had fragmentation of this behavioural state showing more bouts of shorter length than YO mice. OLD mice also had more NREMS bouts and less frequent NREMS apneas than YO mice. Regardless of age, KO mice showed cataplexy-like episodes and shorter REMS latency than WT controls and had a faster breathing rate and an increased minute ventilation during REMS. KO mice also had more wakefulness, NREMS and REMS bouts, and a shorter mean length of wakefulness bouts than WT controls. Our experiment indicated that the lack of orexins as well as ageing importantly modulate the sleep and breathing phenotype in mice. The narcoleptic phenotype caused by orexin deficiency in female mice was substantially preserved with ageing.