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

Determinants of telomere attrition over 1 year in healthy older women: stress and health behaviors matter

Telomere length, a reliable predictor of disease pathogenesis, can be affected by genetics, chronic stress and health behaviors. Cross-sectionally, highly stressed postmenopausal women have shorter telomeres, but only if they are inactive. However, no studies have prospectively examined telomere length change over a short period, and if rate of attrition is affected by naturalistic factors such as stress and engagement in healthy behaviors, including diet, exercise, and sleep. Here we followed healthy women over 1 year to test if major stressors that occurred over the year predicted telomere shortening, and whether engaging in healthy behaviors during this period mitigates this effect. In 239 postmenopausal, non-smoking, disease-free women, accumulation of major life stressors across a 1-year period predicted telomere attrition over the same period-for every major life stressor that occurred during the year, there was a significantly greater decline in telomere length over the year of 35 bp (P<0.05). Yet, these effects were moderated by health behaviors (interaction B=0.19, P=0.04). Women who maintained relatively higher levels of health behaviors (1 s.d. above the mean) appeared to be protected when exposed to stress. This finding has implications for understanding malleability of telomere length, as well as expectations for possible intervention effects. This is the first study to identify predictors of telomere length change over the short period of a year.

Severe chronic insomnia is not associated with higher body mass index

Short sleep duration is widely considered to be a risk factor for weight gain, suggesting that patients suffering from sleep disorders are a risk group. Despite some positive preliminary data on patients with organic sleep disorders, empirical evidence for an increased body mass index in patients with insomnia is scarce. Two-hundred and thirty-three patients with a confirmed diagnosis of severe and chronic insomnia without co-morbidity showing objectively impaired sleep quality were compared with respect to their body mass index with control data derived from a representative population survey matched in gender and age. As a result, patients with insomnia showed a lower body mass index (23.8 kg m(-2) versus 27.1 kg m(-2) ; P < 0.0005). Our findings suggest that patients with chronic insomnia do not exhibit overweight. These data are a valuable educational tool to calm patients' fears about the consequences of insomnia, and contribute to the understanding of chronically disturbed sleep and weight regulation.

Napping reverses the salivary interleukin-6 and urinary norepinephrine changes induced by sleep restriction

CONTEXT

Neuroendocrine and immune stresses imposed by chronic sleep restriction are known to be involved in the harmful cardiovascular effects associated with poor sleep.

OBJECTIVES

Despite a well-known beneficial effect of napping on alertness, its effects on neuroendocrine stress and immune responses after sleep restriction are largely unknown.

DESIGN

This study was a strictly controlled (sleep-wake status, light environment, caloric intake), crossover, randomized design in continuously polysomnography-monitored subjects.

SETTING

The study was conducted in a laboratory-based study.

PARTICIPANTS

The subjects were 11 healthy young men.

INTERVENTION

We investigated the effects on neuroendocrine and immune biomarkers of a night of sleep restricted to 2 h followed by a day without naps or with 30 minute morning and afternoon naps, both conditions followed by an ad libitum recovery night starting at 20:00.

MAIN OUTCOME MEASURES

Salivary interleukin-6 and urinary catecholamines were assessed throughout the daytime study periods.

RESULTS

The increase in norepinephrine values seen at the end of the afternoon after the sleep-restricted night was not present when the subjects had the opportunity to take naps. Interleukin-6 changes observed after sleep deprivation were also normalized after napping. During the recovery day in the no-nap condition, there were increased levels of afternoon epinephrine and dopamine, which was not the case in the nap condition. A recovery night after napping was associated with a reduced amount of slow-wave sleep compared to after the no-nap condition.

CONCLUSIONS

Our data suggest that napping has stress-releasing and immune effects. Napping could be easily applied in real settings as a countermeasure to the detrimental health consequences of sleep debt.

How are normal sleeping controls selected? A systematic review of cross-sectional insomnia studies and a standardized method to select healthy controls for sleep research

There appears to be some inconsistency in how normal sleepers (controls) are selected and screened for participation in research studies for comparison with insomnia patients. The purpose of the current study is to assess and compare methods of identifying normal sleepers in insomnia studies, with reference to published standards. We systematically reviewed the literature on insomnia patients, which included control subjects. The resulting 37 articles were systematically reviewed with reference to the five criteria for normal sleep specified by Edinger et al. In summary, these criteria are as follows: evidence of sleep disruption, sleep scheduling, general health, substance/medication use, and other sleep disorders. We found sleep diaries, polysomnography (PSG), and clinical screening examinations to be widely used with both control subjects and insomnia participants. However, there are differences between research groups in the precise definitions applied to the components of normal sleep. We found that none of the reviewed studies applied all of the Edinger et al. criteria, and 16% met four criteria. In general, screening is applied most rigorously at the level of a clinical disorder, whether physical, psychiatric, or sleep. While the Edinger et al. criteria seem to be applied in some form by most researchers, there is scope to improve standards and definitions in this area. Ideally, different methods such as sleep diaries and questionnaires would be used concurrently with objective measures to ensure normal sleepers are identified, and descriptive information for control subjects would be reported. Here, we have devised working criteria and methods to be used for the assessment of normal sleepers. This would help clarify the nature of the control group, in contrast to insomnia subjects and other patient groups.

Preoperative sleep complaints are associated with poor physical recovery in the months following cardiac surgery

BACKGROUND

Sleep disturbance is associated with poorer outcomes in cardiac patients, but little is known about the independent role of sleep quality in coronary artery bypass graft (CABG) patients.

PURPOSE

This study aims to examine the relationship between preoperative sleep complaints and post-operative emotional and physical recovery in CABG surgery patients, independently of demographic, clinical and mood factors.

METHODS

Two hundred thirty CABG patients (aged 67.81 ± 9.07 years) completed measures of self-reported sleep complaints before surgery and health-related quality of life (HRQoL), physical symptoms and pain 2 months after surgery.

RESULTS

Greater sleep complaints prior to surgery were associated with greater physical symptoms, poorer physical HRQoL and greater sensory pain after surgery (p < 0.05), but not with affective pain or mental HRQoL. Preoperative mood was not able to explain these associations.

CONCLUSIONS

Sleep complaints may be implicated in physical recovery from CABG surgery but further work is needed to understand the role of causal pathways.

Effects of sleep deprivation on action potential and transient outward potassium current in ventricular myocytes in rats

BACKGROUND

Sleep deprivation contributes to the development and recurrence of ventricular arrhythmias. However, the electrophysiological changes in ventricular myocytes in sleep deprivation are still unknown.

MATERIAL AND METHODS

Sleep deprivation was induced by modified multiple platform technique. Fifty rats were assigned to control and sleep deprivation 1, 3, 5, and 7 days groups, and single ventricular myocytes were enzymatically dissociated from rat hearts. Action potential duration (APD) and transient outward current (Ito) were recorded using whole-cell patch clamp technique.

RESULTS

Compared with the control group, the phases of APD of ventricular myocytes in 3, 5, and 7 days groups were prolonged and APD at 20% and 50% level of repolarization (APD20 and APD50) was significantly elongated (The APD20 values of control, 1, 3, 5, and 7 days groups: 5.66±0.16 ms, 5.77±0.20 ms, 8.28±0.30 ms, 11.56±0.32 ms, 13.24±0.56 ms. The APD50 values: 50.66±2.16 ms, 52.77±3.20 ms, 65.28±5.30 ms, 83.56±7.32 ms, 89.24±5.56 ms. P<0.01, n=18). The current densities of Ito significantly decreased. The current density-voltage (I-V) curve of Ito was vitally suppressed downward. The steady-state inactivation curve and steady-state activation curve of Ito were shifted to left and right, respectively, in sleep deprivation rats. The inactivation recovery time of Ito was markedly retarded and the time of closed-state inactivation was markedly accelerated in 3, 5, and 7 days groups.

CONCLUSIONS

APD of ventricular myocytes in sleep deprivation rats was significantly prolonged, which could be attributed to decreased activation and accelerated inactivation of Ito.

Evaluation of the association of sleep apnea-related systemic inflammation with CRP, ESR, and neutrophil-to-lymphocyte ratio

Background

Obstructive sleep apnea syndrome (OSAS) is characterized by cyclic episodes of hypoxemia and reoxygenation. It has been suggested that OSAS is associated with chronic inflammation within the microvasculature. This low-grade inflammation may play a role in the pathophysiology of OSAS-related comorbidities. Evaluation of the inflammatory markers may predict the degree of the systemic inflammation and this may be a prognostic factor for future adverse events such as cardiovascular risks. Proinflammatory cytokines have been extensively studied in sleep-disordered breathing. Neutrophil-to-lymphocyte ratio is a recently described indicator of systemic inflammation, but it has not been studied in OSAS patients. In this study we aimed to evaluate the easily measurable parameters of systemic inflammation in these patients. We conducted this study to examine the association among OSAS and C- reactive protein, erythrocyte sedimentation rate, and neutrophil-to-lymphocyte ratio.

Material/Methods

OSAS patients who underwent overnight polysomnography were studied retrospectively. They were divided into 4 groups: control, mild, moderate, and severe OSAS patients. Blood test results and inflammatory markers were compared between the groups. One-way ANOVA and Kruskall-Wallis H test were used for statistical analysis.

Results

A total of 147 patients were included in the study. No differences in evaluated inflammatory markers were observed among the 4 groups.

Conclusions

Evaluation of the OSAS-related systemic inflammation is not likely to be possible by CRP, ESR, or neutrophil-to-lymphocyte ratio measurements. These markers do not seem to be associated with the degree of the upper airway obstruction.

Oxalic acid and diacylglycerol 36:3 are cross-species markers of sleep debt

Sleep is an essential biological process that is thought to have a critical role in metabolic regulation. In humans, reduced sleep duration has been associated with risk for metabolic disorders, including weight gain, diabetes, obesity, and cardiovascular disease. However, our understanding of the molecular mechanisms underlying effects of sleep loss is only in its nascent stages. In this study we used rat and human models to simulate modern-day conditions of restricted sleep and addressed cross-species consequences via comprehensive metabolite profiling. Serum from sleep-restricted rats was analyzed using polar and nonpolar methods in two independent datasets (n = 10 per study, 3,380 measured features, 407 identified). A total of 38 features were changed across independent experiments, with the majority classified as lipids (18 from 28 identified). In a parallel human study, 92 metabolites were identified as potentially significant, with the majority also classified as lipids (32 of 37 identified). Intriguingly, two metabolites, oxalic acid and diacylglycerol 36:3, were robustly and quantitatively reduced in both species following sleep restriction, and recovered to near baseline levels after sleep restriction (P < 0.05, false-discovery rate < 0.2). Elevated phospholipids were also noted after sleep restriction in both species, as well as metabolites associated with an oxidizing environment. In addition, polar metabolites reflective of neurotransmitters, vitamin B3, and gut metabolism were elevated in sleep-restricted humans. These results are consistent with induction of peroxisome proliferator-activated receptors and disruptions of the circadian clock. The findings provide a potential link between known pathologies of reduced sleep duration and metabolic dysfunction, and potential biomarkers for sleep loss.

The effects of ethnic/racial discrimination and sleep quality on depressive symptoms and self-esteem trajectories among diverse adolescents

Ethnic/racial discrimination has persistent negative implications for both physical and mental health. The current study employs a risk and resilience framework to explore the joint effects of ethnic/racial discrimination and sleep disturbance on psychosocial outcomes among adolescents. In a sample of 146 minority and White adolescents (70% female), changes in depressive symptoms, anxiety, and self-esteem over 3 years are explored using growth curve models. Regardless of ethnic background, adolescents reporting high levels of ethnic/racial discrimination and poor sleep also reported a corresponding increase in depressive symptoms and lower levels of self-esteem over time. Adolescents reporting all other combinations of sleep quality and ethnic/racial discrimination reported more positive adjustment over time. The joint effects of sleep and ethnic/racial discrimination on adolescent psychosocial development are discussed.

Chronically restricted or disrupted sleep as a causal factor in the development of depression

Sleep problems are a common complaint in the majority of people suffering from depression. While sleep complaints were traditionally seen as a symptom of mood disorders, accumulating evidence suggests that in many cases the relationship may be reverse as well. A long list of longitudinal studies shows that sleep complaints often precede the onset of depression and constitute an independent risk factor for the development of the disorder. Additionally, experimental studies in animals show that chronically restricted or disrupted sleep may gradually induce neurobiological changes that are very similar to what has been reported for depressed patients. The mechanisms through which insufficient sleep increases the risk for depression are poorly understood but may include effects of sleep disturbance on neuroendocrine stress systems, serotonergic neurotransmission, and various interacting signaling pathways involved in the regulation of neuronal plasticity and neurogenesis. Because sleep is considered to play a crucial role in regulating neuronal plasticity and synaptic strength, chronically insufficient sleep may contribute to depression through an impairment of these plasticity processes leading to altered connectivity and communication within and between brain regions involved in the regulation of mood.

Sleep deprived and sweating it out: the effects of total sleep deprivation on skin conductance reactivity to psychosocial stress

STUDY OBJECTIVES

We examined how sleep deprivation alters physiological responses to psychosocial stress by evaluating changes in skin conductance.

DESIGN

Between-subjects design with one group allocated to 24 h of total sleep deprivation and the other to rested wakefulness.

SETTING

The study took place in a research laboratory.

PARTICIPANTS

Participants were 40 healthy young adults recruited from a university.

INTERVENTIONS

Sleep deprivation and feedback.

MEASUREMENTS AND RESULTS

Electrodermal activity was monitored while participants completed a difficult perceptual task with false feedback. All participants showed increased skin conductance levels following stress. However, compared to well-rested participants, sleep deprived participants showed higher skin conductance reactivity with increasing stress levels.

CONCLUSIONS

Our results suggest that sleep deprivation augments allostatic responses to increasing psychosocial stress. Consequentially, we propose sleep loss as a risk factor that can influence the pathogenic effects of stress.

Salivary α-Amylase Reactivity to Laboratory Social Stress With and Without Acute Sleep Restriction

A growing literature suggests that salivary α-amylase (sAA) may serve as a minimally invasive marker of psychophysiological stress-induced activity of the sympathetic-adrenal-medullary system (SAM). Previous inconsistencies in the experimental literature relating sAA response to short sleep duration may be as a result of poor reliability of self-reported sleep time, suggesting that further examination of sAA response following verified sleep loss is required. With regard to the potential usefulness of sAA as a biomarker of psychosocial stress in the laboratory, previous research has also relied primarily on traditional psychosocial stress protocols, including physically present evaluative observers. The present study aimed to examine sAA response following a period of verified acute sleep restriction compared to a rested condition, in addition to examining the sensitivity of sAA response to a laboratory stress protocol that exposed participants to negative social evaluation presented by video relay. One hundred and eight healthy young adults (age 17–22 years; M = 18.39 years, SD = 0.87) completed a laboratory social stress task and provided saliva samples pre- and post-stressor presentation, after a night of partial sleep restriction or a full night’s rest. Marked increases in sAA activity to the video-relayed stressor were observed in both rested and sleep restricted groups. Further, sleep restricted participants exhibited significantly increased basal levels of sAA activity. The data corroborate previous limited data indicating a general upregulation of sAA activity following poor sleep and support previous findings concerning the efficacy of an experimental paradigm that presents laboratory social stress by means of video recording.

Associations between Poor Sleep Quality and Stages of Change of Multiple Health Behaviors among Participants of Employee Wellness Program

OBJECTIVE

Using the Transtheoretical Model of behavioral change, this study evaluates the relationship between sleep quality and the motivation and maintenance processes of healthy behavior change.

METHODS

The current study is an analysis of data collected in 2008 from an online health risk assessment (HRA) survey completed by participants of the Kansas State employee wellness program (N=13,322). Using multinomial logistic regression, associations between self-reported sleep quality and stages of change (i.e. precontemplation, contemplation, preparation, action, maintenance) in five health behaviors (stress management, weight management, physical activities, alcohol use, and smoking) were analyzed.

RESULTS

Adjusted for covariates, poor sleep quality was associated with an increased likelihood of contemplation, preparation, and in some cases action stage when engaging in the health behavior change process, but generally a lower likelihood of maintenance of the healthy behavior.

CONCLUSIONS

The present study demonstrated that poor sleep quality was associated with an elevated likelihood of contemplating or initiating behavior change, but a decreased likelihood of maintaining healthy behavior change. It is important to include sleep improvement as one of the lifestyle management interventions offered in EWP to comprehensively reduce health risks and promote the health of a large employee population.

Social relationships play a role in sleep status in Chinese undergraduate students

The purpose of this study was to examine whether social relationships were associated with sleep status in Chinese undergraduate students. A cross-sectional questionnaire survey was conducted in November 2012 at Huzhou Teachers College, China. The questionnaire involved demographic characteristics, personal lifestyle habits, social relationships and Pittsburgh Sleep Quality Index (PSQI). The associations between social relationships and sleep status were analyzed by using regression models after adjustment for potential factors. Poor sleep quality was prevalent among Chinese undergraduate students. Men tended to have better sleep than women. Lower social stress, better management of stress and good social support were correlated with better sleep status, and stress or support from friends, family and classmates were all related with sleep variables. While only weak associations between number of friends and sleep were detected. The results were consistent in men and women. Educators and instructors should be aware of the importance of social relationships as well as healthy sleep in undergraduates.

Heart rate variability: a tool to explore the sleeping brain?

Sleep is divided into two main sleep stages: (1) non-rapid eye movement sleep (non-REMS), characterized among others by reduced global brain activity; and (2) rapid eye movement sleep (REMS), characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV) analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. Moreover, HRV analysis combined with brain imaging has identified close connectivity between autonomic cardiac modulation and activity in brain areas such as the amygdala and insular cortex during REMS, but no connectivity between brain and cardiac activity during non-REMS. There is also some evidence for an association between HRV and dream intensity and emotionality. Following some technical considerations, this review addresses how brain activity during sleep contributes to changes in autonomic cardiac activity, organized into three parts: (1) the knowledge on autonomic cardiac control, (2) differences in brain and autonomic activity between non-REMS and REMS, and (3) the potential of HRV analysis to explore the sleeping brain, and the implications for psychiatric disorders.

Sleep in elite athletes and nutritional interventions to enhance sleep

Sleep has numerous important physiological and cognitive functions that may be particularly important to elite athletes. Recent evidence, as well as anecdotal information, suggests that athletes may experience a reduced quality and/or quantity of sleep. Sleep deprivation can have significant effects on athletic performance, especially submaximal, prolonged exercise. Compromised sleep may also influence learning, memory, cognition, pain perception, immunity and inflammation. Furthermore, changes in glucose metabolism and neuroendocrine function as a result of chronic, partial sleep deprivation may result in alterations in carbohydrate metabolism, appetite, food intake and protein synthesis. These factors can ultimately have a negative influence on an athlete’s nutritional, metabolic and endocrine status and hence potentially reduce athletic performance. Research has identified a number of neurotransmitters associated with the sleep–wake cycle. These include serotonin, gamma-aminobutyric acid, orexin, melanin-concentrating hormone, cholinergic, galanin, noradrenaline, and histamine. Therefore, nutritional interventions that may act on these neurotransmitters in the brain may also influence sleep. Carbohydrate, tryptophan, valerian, melatonin and other nutritional interventions have been investigated as possible sleep inducers and represent promising potential interventions. In this review, the factors influencing sleep quality and quantity in athletic populations are examined and the potential impact of nutritional interventions is considered. While there is some research investigating the effects of nutritional interventions on sleep, future research may highlight the importance of nutritional and dietary interventions to enhance sleep.

Effects of mental resilience on neuroendocrine hormones level changes induced by sleep deprivation in servicemen

The aim of this study was to investigate the effects of mental resilience on the changes of serum rennin, angiotensin, and cortisol level induced by sleep deprivation in servicemen. By random cluster sampling, a total of 160 servicemen, aged from 18 to 30, were selected to undergo 24-hour total sleep deprivation and administered the military personnel mental resilience scale after the deprivation procedure. The sleep deprivation procedure started at 8 a.m. on Day 8 and ended at 8 a.m. on Day 9 after 7 days of normal sleep for baseline preparation. Blood samples were drawn from the 160 participants at 8 a.m. respectively on Day 8 and Day 9 for hormonal measurements. All blood samples were analyzed using radioimmunoassay. As hypothesized, serum rennin, angiotensin II, and cortisol level of the participants after sleep deprivation were significantly higher than those before (P < 0.05). The changes of serum rennin and cortisol in the lower mental resilience subgroup were significantly greater (P < 0.05); problem-solving skill and willpower were the leading influence factors for the increases of serum rennin and cortisol respectively induced by sleep deprivation. We conclude that mental resilience plays a significant role in alleviating the changes of neurohormones level induced by sleep deprivation in servicemen.

Movement distribution: a new measure of sleep fragmentation in children with upper airway obstruction

STUDY OBJECTIVES

To develop a measure of sleep fragmentation in children with upper airway obstruction based on survival curve analysis of sleep continuity.

DESIGN

Prospective repeated measures.

SETTING

Hospital sleep laboratory.

PARTICIPANTS

92 children aged 3.0 to 12.9 years undergoing 2 overnight polysomnographic (PSG) sleep studies, 6 months apart. Subjects were divided into 3 groups based on their obstructive apnea and hypopnea index (OAHI) and other upper airway obstruction (UAO) symptoms: primary snorers (PS; n = 24, OAHI <1), those with obstructive sleep apnea syndrome (OSAS; n = 20, OAHI ≥1) and non-snoring controls (C; n = 48, OAHI <1).

INTERVENTIONS

Subjects in the PS and OSAS groups underwent tonsillectomy and adenoidectomy between PSG assessments.

MEASUREMENTS AND RESULTS

Post hoc measures of movement and contiguous sleep epochs were exported and analyzed using Kaplan-Meier estimates of survival to generate survival curves for the 3 groups. Statistically significant differences were found between these group curves for sleep continuity (P < 0.05) when using movement events as the sleep fragmenting event, but not if stage 1 NREM sleep or awakenings were used.

CONCLUSION

Using conventional indices of sleep fragmentation in survival curve analysis of sleep continuity does not provide a useful measure of sleep fragmentation in children with upper airway obstruction. However, when sleep continuity is defined as the time between gross body movements, a potentially useful clinical measure is produced.

Chronic sleep restriction during pregnancy--repercussion on cardiovascular and renal functioning of male offspring

Changes in the maternal environment can induce fetal adaptations that result in the progression of chronic diseases in the offspring. The objective of the present study was to evaluate the effects of maternal chronic sleep restriction on blood pressure, renal function and cardiac baroreflex response on male offspring at adult age. Female 3-month-old Wistar rats were divided in two experimental groups: control (C) and chronic sleep restricted (CSR). Pregnancy was confirmed by vaginal smear. Chronic sleep restricted females were subjected to sleep restriction by the multiple platform technique for 20 h daily, between the 1^st and 20^th day of pregnancy. After birth, the litters were reduced to 6 rats per mother, and were designated as offspring from control (OC) and offspring from chronic sleep restricted (OCSR). Indirect blood pressure (BPi – tail cuff) was measured by plethysmography in male offspring at 3 months old. Following, the renal function and cardiac baroreflex response were analyzed. Values of BPi in OCSR were significantly higher compared to OC [OC: 127±2.6 (19); OCSR: 144±2.5 (17) mmHg]. The baroreflex sensitivity to the increase of blood pressure was reduced in OCSR [Slope: OC: −2.6±0.15 (9); OCRS: −1.6±0.13 (9)]. Hypothalamic activity of ACE2 was significantly reduced in OCSR compared to OC [OC: 97.4±15 (18); OSR: 60.2±3.6 (16) UAF/min/protein mg]. Renal function alteration was noticed by the increase in glomerular filtration rate (GFR) observed in OCSR [OC: 6.4±0.2 (10); OCSR: 7.4±0.3 (7)]. Chronic sleep restriction during pregnancy caused in the offspring hypertension, altered cardiac baroreflex response, reduced ACE-2 activity in the hypothalamus and renal alterations. Our data suggest that the reduction of sleeping time along the pregnancy is able to modify maternal homeostasis leading to functional alterations in offspring.

Chronic sleep fragmentation induces endothelial dysfunction and structural vascular changes in mice

STUDY OBJECTIVES

Sleep fragmentation (SF) is a common occurrence and constitutes a major characteristic of obstructive sleep apnea (OSA). SF has been implicated in multiple OSA-related morbidities, but it is unclear whether SF underlies any of the cardiovascular morbidities of OSA. We hypothesized that long-term SF exposures may lead to endothelial dysfunction and altered vessel wall structure.

METHODS AND RESULTS

Adult male C57BL/6J mice were fed normal chow and exposed to daylight SF or control sleep (CTL) for 20 weeks. Telemetric blood pressure and endothelial function were assessed weekly using a modified laser-Doppler hyperemic test. Atherosclerotic plaques, elastic fiber disruption, lumen area, wall thickness, foam cells, and macrophage recruitment, as well as expression of senescence-associated markers were examined in excised aortas. Increased latencies to reach baseline perfusion levels during the post-occlusive period emerged in SF mice with increased systemic BP values starting at 8 weeks of SF and persisting thereafter. No obvious atherosclerotic plaques emerged, but marked elastic fiber disruption and fiber disorganization were apparent in SF-exposed mice, along with increases in the number of foam cells and macrophages in the aorta wall. Senescence markers showed reduced TERT and cyclin A and increased p16INK4a expression, with higher IL-6 plasma levels in SF-exposed mice.

CONCLUSIONS

Long-term sleep fragmentation induces vascular endothelial dysfunction and mild blood pressure increases. Sleep fragmentation also leads to morphologic vessel changes characterized by elastic fiber disruption and disorganization, increased recruitment of inflammatory cells, and altered expression of senescence markers, thereby supporting a role for sleep fragmentation in the cardiovascular morbidity of OSA.

Multiple time courses of salivary alpha-amylase and dimensions of affect in adolescence

Previous research has illustrated associations among daily experiences, emotions and stress-responding physiological systems. Recently, investigators have examined salivary alpha-amylase (sAA), a surrogate marker of the autonomic nervous system, and its associations with affect. The current study examined associations among affective valence, arousal and sAA across three different time courses at the momentary, daily and inter-individual level to understand varying influences of adolescents' daily emotional experiences on sAA reactivity and diurnal sAA activity. Adolescents (N=82) provided salivary samples and diary reports of affect and experiences five times a day for three consecutive days. They also completed self-report questionnaires on trait affect. Findings from multilevel growth curves demonstrated that adolescents in our sample displayed typical sAA diurnal rhythms with levels dropping 30 min after waking and then increasing across the day to a peak in the late afternoon. Within person momentary experiences of high arousal positive affect were associated with momentary sAA reactivity. Prior day experiences of high arousal negative affect were associated with a greater amylase awakening response (i.e., greater decrease) and flatter slopes the next day. Trait positive affect was also associated with flatter sAA slopes. Our findings suggest that both affective arousal and valence should be accounted for when examining differences in sAA reactivity and diurnal patterns. Further, our results indicated that emotion-physiology transactions among adolescents occur over varying time scales for salivary alpha-amylase as well as cortisol.

Improvements in sleep problems among the chronic disease self-management program participants

Sleep is increasingly important in public health because sleep problems are associated with multiple negative health and quality-of-life outcomes, especially among those with chronic conditions. While evidence-based self-management programs have been widely studied, little is known about their specific impacts on sleep. Using data from the National Study of Chronic Disease Self-Management Program (n = 1168), improvements in sleep problems were observed for all subgroups except men. More sleep problem reductions were observed among younger participants compared with their older counterparts. This study confirmed the value of self-management programs for ameliorating sleep problems across diverse participant groups.

When time stands still: an integrative review on the role of chronodisruption in posttraumatic stress disorder

PURPOSE OF REVIEW

The human circadian system creates and maintains cellular and systemic rhythmicity essential to homeostasis. Loss of circadian rhythmicity fundamentally affects the neuroendocrine, immune and autonomic system, similar to chronic stress and, thus, may play a central role in the development of stress-related disorders. This article focuses on the role of circadian misalignment in the pathophysiology of posttraumatic stress disorder (PTSD).

RECENT FINDINGS

Sleep disruption is a core feature of PTSD supporting the important supraordinate pathophysiological role of circadian system in PTSD. Furthermore, direct and indirect human and animal PTSD research suggests circadian system linked neuroendocrine, immune, metabolic and autonomic dysregulation with blunted diurnal rhythms, specific sleep pattern pathologies and cognitive deficits, as well as endocannabinoid and neuropeptide Y system alterations and altered circadian gene expression, linking circadian misalignment to PTSD pathophysiology.

SUMMARY

PTSD development is associated with chronodisruption findings. Evaluation and treatment of sleep and circadian disruption should be the first steps in PTSD management. State-of-the-art methods of circadian rhythm assessment should be applied to bridge the gap between clinical significance and limited understanding of the relationship between traumatic stress, sleep and circadian system.

Adverse effects of two nights of sleep restriction on the hypothalamic-pituitary-adrenal axis in healthy men

CONTEXT

Insufficient sleep is associated with increased cardiometabolic risk. Alterations in hypothalamic-pituitary-adrenal axis may underlie this link.

OBJECTIVE

Our objective was to examine the impact of restricted sleep on daytime profiles of ACTH and cortisol concentrations.

METHODS

Thirteen subjects participated in 2 laboratory sessions (2 nights of 10 hours in bed versus 2 nights of 4 hours in bed) in a randomized crossover design. Sleep was polygraphically recorded. After the second night of each session, blood was sampled at 20-minute intervals from 9:00 am to midnight to measure ACTH and total cortisol. Saliva was collected every 20 minutes from 2:00 pm to midnight to measure free cortisol. Perceived stress, hunger, and appetite were assessed at hourly intervals by validated scales.

RESULTS

Sleep restriction was associated with a 19% increase in overall ACTH levels (P < .03) that was correlated with the individual amount of sleep loss (rSp = 0.63, P < .02). Overall total cortisol levels were also elevated (+21%; P = .10). Pulse frequency was unchanged for both ACTH and cortisol. Morning levels of ACTH were higher after sleep restriction (P < .04) without concomitant elevation of cortisol. In contrast, evening ACTH levels were unchanged while total and free cortisol increased by, respectively, 30% (P < .03) and 200% (P < .04). Thus, the amplitude of the circadian cortisol decline was dampened by sleep restriction (-21%; P < .05). Sleep restriction was not associated with higher perceived stress but resulted in an increase in appetite that was correlated with the increase in total cortisol.

CONCLUSION

The impact of sleep loss on hypothalamic-pituitary-adrenal activity is dependent on time of day. Insufficient sleep dampens the circadian rhythm of cortisol, a major internal synchronizer of central and peripheral clocks.

Sleep complaints predict increases in resting blood pressure following marital separation

OBJECTIVE

Although marital separation and divorce are associated with many negative health outcomes, few studies examine the psychophysiological mechanisms that may give rise to these outcomes. This study examined changes in resting blood pressure (BP) as a function of sleep complaints in recently divorced adults.

METHOD

Recently separated adults (n = 138; 38 men) completed a self-report measure of sleep complaints and a resting blood pressure (BP) assessment in the laboratory at three occasions across 7.5 months.

RESULTS

Multilevel analyses revealed that although sleep complaints were not associated with concurrent BP, sleep complaints predicted significant increases in both systolic and diastolic BP at the subsequent laboratory visit. In addition, time since the separation from an ex-partner moderated the association between sleep complaints at baseline and resting systolic blood pressure (SBP) 3 months later. People who reported high sleep complaints 10 weeks or more after their separation demonstrated greater increases in SBP.

CONCLUSIONS

In recently separated adults, greater sleep complaints may index increased risk for future increases in BP. This work helps pinpoint one potential mechanistic pathway linking marital separation with an important, health-relevant biological outcome.

Sleep complaints and incident disability in a community-based cohort study of older persons

OBJECTIVE

Sleep complaints are associated with adverse health consequences. We hypothesized that non-disabled older persons with more sleep complaints have an increased risk of developing disability.

METHODS

Subjects included 908 older clergy participating in the Religious Order Study without clinical dementia, history of stroke, or Parkinson disease. At baseline, participants rated their difficulty falling asleep, frequency of nocturnal awakenings, sleep efficacy, and napping frequency, from which a summary dyssomnia measure was derived. Self-report assessment of disability included instrumental activities of daily living (IADLs), basic activities of daily living (ADLs), and Rosow-Breslau mobility disability at baseline and at annual evaluations.

RESULTS

Mean follow-up was 9.6 (SD: 4.2) years. At baseline, more than 60% had one or more sleep complaints. In a series of Cox proportional hazards models controlling for age, sex, and education, a one-point higher dyssomnia score at baseline was associated with about 20% increased risk of IADL disability (hazard ratio: 1.20; 95% confidence interval [CI]: 1.04-1.39; χ(2)1 = 7.62; p <0.05), about 27% increased risk of ADL disability (hazard ratio: 1.27; 95% CI: 1.10-1.47; χ(2)1 = 12.15; p <0.01), and about 27% increased risk of mobility disability (hazard ratio: 1.27; 95% CI: 1.09-1.48; χ(2)1 = 11.04; p <0.01). These associations did not vary by age, sex, or education and remained significant after controlling for potential confounders including body mass index, chronic medical conditions, and several common medications. Controlling for depressive symptoms attenuated the association between sleep complaints and incident IADL and ADL disabilities but the association between sleep complaints and incident mobility disability remained significant.

CONCLUSION

Non-disabled older adults with more sleep complaints have an increased risk of developing disability.

Insomnia in adult survivors of childhood cancer: a report from project REACH

PURPOSE

Insomnia is a common problem affecting cancer survivors even years after completion of therapy. Childhood cancer survivors may be at particular risk due to vulnerability to the effects of treatment and medical late effects which impact normal sleep development. Using an indicator of clinically significant insomnia (sleep efficiency), we examined a group of adult survivors of childhood cancer to (1) describe clinical insomnia rates, (2) identify physical and psychological correlates of insomnia, and (3) investigate the frequency with which sleep issues were evaluated during a cancer survivorship medical visit.

METHODS

A total of 122 adult survivors of childhood cancer completed standard measures of sleep, psychological distress, and health-related quality of life. Medical records of the 75 survivors with a survivorship medical visit on the day of self-report measure completion were reviewed for documentation of sleep-related issues.

RESULTS

Twenty-eight percent of participants endorsed sleep efficiency below 85 %, indicating clinically significant insomnia. Insomnia was associated with poor physical health and anxiety but not with demographic or cancer treatment variables. Medical providers failed to document sleep in visit notes for 67 % of patients with self-reported insomnia.

CONCLUSIONS

A significant proportion of adult survivors of childhood cancer report insomnia, which is associated with physical and psychological health. Few survivors with insomnia discuss this issue with oncology providers during survivorship care. There is a clear need to screen for insomnia in this population. Patients and providers should take greater responsibility for discussing sleep issues and seeking out proper treatment referrals when it is identified.

One night of partial sleep deprivation affects habituation of hypothalamus and skin conductance responses

Sleep disturbances are prevalent in clinical anxiety, but it remains unclear whether they are cause and/or consequence of this condition. Fear conditioning constitutes a valid laboratory model for the acquisition of normal and pathological anxiety. To explore the relationship between disturbed sleep and anxiety in more detail, the present study evaluated the effect of partial sleep deprivation (SD) on fear conditioning in healthy individuals. The neural correlates of 1) nonassociative learning and physiological processing and 2) associative learning (differential fear conditioning) were addressed. Measurements entailed simultaneous functional MRI, EEG, skin conductance response (SCR), and pulse recordings. Regarding nonassociative learning, partial SD resulted in a generalized failure to habituate during fear conditioning, as evidenced by reduced habituation of SCR and hypothalamus responses to all stimuli. Furthermore, SCR and hypothalamus activity were correlated, supporting their functional relationship. Regarding associative learning, effects of partial SD on the acquisition of conditioned fear were weaker and did not reach statistical significance. The hypothalamus plays an integral role in the regulation of sleep and autonomic arousal. Thus sleep disturbances may play a causal role in the development of normal and possibly pathological fear by increasing the susceptibility of the sympathetic nervous system to stressful experiences.

Parents of children with physical disabilities - perceived health in parents related to the child's sleep problems and need for attention at night

BACKGROUND

Approximately half of all children with moderate to severe physical disabilities have persistent sleep problems and many of these children need parental attention at night.

AIM

To study whether sleep problems and need for night-time attention among children with physical disabilities are associated with perceived parental health, headache, psychological exhaustion, pain due to heavy lifting, night-time wakefulness and disrupted sleep.

METHODS

We asked parents of 377 children with physical disabilities aged 1-16 years to complete a questionnaire about their own health. The children all lived at home with both parents.

RESULTS

Both parents reported poor health, psychological exhaustion, more night-time wakefulness and disrupted sleep when the child had sleep problems (P < 0.05). Mothers also reported more headache when the child had sleep problems (P = 0.001). Both parents reported more night-time wakefulness and disrupted sleep when the child needed night-time attention (P < 0.01). In general, mothers reported significantly poorer health, more night-time wakefulness, disrupted sleep, headache and psychological exhaustion than fathers (P < 0.001).

CONCLUSIONS

Sleep problems need to be acknowledged within the paediatric setting in order to prevent psychological exhaustion and poor health in mothers and fathers of children with physical disabilities.

Sleep duration and risk of stroke mortality among Chinese adults: Singapore Chinese health study

BACKGROUND AND PURPOSE

Prospective relation between sleep duration and stroke risk is less studied, particularly in Asians. We examined the association between sleep duration and stroke mortality among Chinese adults.

METHODS

The Singapore Chinese Health Study is a population-based cohort of 63 257 Chinese adults aged 45 to 74 years enrolled during 1993 through 1998. Sleep duration at baseline was assessed via in-person interview, and death information during follow-up was ascertained via record linkage with the death registry up to December 31, 2011. Cox proportional hazard models were used to calculate hazard ratios with adjustment for other comorbidities and lifestyle risk factors of stroke mortality.

RESULTS

During 926 752 person-years of follow-up, we documented 1381 stroke deaths (322 from hemorrhagic and 1059 from ischemic or nonspecified strokes). Compared with individuals with 7 hours per day of sleep, the multivariate-adjusted hazard ratio (95% confidence interval) of total stroke mortality was 1.25 (1.05-1.50) for ≤5 hours per day (short duration), 1.01 (0.87-1.18) for 6 hours per day, 1.09 (0.95-1.26) for 8 hours per day, and 1.54 (1.28-1.85) for ≥9 hours per day (long duration). The increased risk of stroke death with short (1.54; 1.16-2.03) and long durations of sleep (1.95; 1.48-2.57) was seen among subjects with a history of hypertension, but not in those without hypertension. These findings were limited to risk of death from ischemic or nonspecified stroke, but not observed for hemorrhagic stroke.

CONCLUSIONS

Both short and long sleep durations are associated with increased risk of stroke mortality in a Chinese population, particularly among those with a history of hypertension.

Effects of simulated domestic and international air travel on sleep, performance, and recovery for team sports

The present study examined effects of simulated air travel on physical performance. In a randomized crossover design, 10 physically active males completed a simulated 5-h domestic flight (DOM), 24-h simulated international travel (INT), and a control trial (CON). The mild hypoxia, seating arrangements, and activity levels typically encountered during air travel were simulated in a normobaric, hypoxic altitude room. Physical performance was assessed in the afternoon of the day before (D - 1 PM) and in the morning (D + 1 AM) and afternoon (D + 1 PM) of the day following each trial. Mood states and physiological and perceptual responses to exercise were also examined at these time points, while sleep quantity and quality were monitored throughout each condition. Sleep quantity and quality were significantly reduced during INT compared with CON and DOM (P < 0.01). Yo-Yo Intermittent Recovery level 1 test performance was significantly reduced at D + 1 PM following INT compared with CON and DOM (P < 0.01), where performance remained unchanged (P > 0.05). Compared with baseline, physiological and perceptual responses to exercise, and mood states were exacerbated following the INT trial (P < 0.05). Attenuated intermittent-sprint performance following simulated international air travel may be due to sleep disruption during travel and the subsequent exacerbated physiological and perceptual markers of fatigue.

Cardiovascular function alterations induced by acute paradoxical sleep deprivation in rats

Sleep loss has been implicated in triggering the hypertension. The goal of the present study was investigated the possible mechanisms underlying cardiovascular alterations after acute paradoxical sleep deprivation (PSD). Male Wistar rats were assigned in two experimental groups: (1) control and (2) PSD for 24 h using the modified single platform method. Paradoxical sleep deprived rats exhibited higher blood pressure, heart rate (HR) and impaired baroreceptor sensitivity. After pharmacological autonomic double blockade (propranolol and methylatropine administration), intrinsic heart rate was decreased after PSD. The PSD rats showed a reduction in the vagal tone without affecting sympathetic tone. Isoproterenol administration (0.001, 0.01 and 1 µg/kg) induced an increase in ΔHR responses in PSD group. Electrocardiographic analysis in response to β-adrenergic stimulation indicated that PSD contributed to ventricular cardiac arrhythmias. Our findings suggest that acute paradoxical sleep loss induce cardiovascular alterations, autonomic imbalance accompanied by impaired baroreflex sensitivity and increased arrhythmia susceptibility.

Development and comparative evaluation of new shapes of pillows

The purpose of this study was to determine pillow designs suitable for supine and side-lying positions. [Subjects] Twenty female and twenty male subjects with a mean age of 22.7 years (SD = 1.3) participated in the study. [Methods] First, a three-dimensional motion analysis system was used to analyze the movements of the head and the shoulder joints during changes from supine positions to side-lying positions. Second, the height from the face to the shoulder and the height from the floor to the middle of the neck in a side-lying position were measured. Third, the weight distribution ratios of the head and the trunk were compared using general pillows (polyester sponge), memory foam, and prototype pillows. [Results] During position changes from supine positions to side-lying positions, the head moved in a fan shape, and the shoulder joint moved an average of 4.4 cm upward. The height from the face to the shoulder was 9 cm on average. The height from the floor to the middle of the neck was 11 cm on average. The weight distribution ratios between the head and the trunk were compared among general pillows (polyester sponge), memory foam, and prototype pillows. The results showed significant differences in the side-lying position. [Conclusion] Pillows with uniform heights are not suitable for a supine or side-lying position. In the case of both positions, users should be allowed to select pillows in shapes that can support the neck.

The development of a questionnaire to assess sleep-related practices, beliefs, and attitudes

There are no established questionnaires that evaluate habitual sleep practices in the context of beliefs and attitudes about sleep. This study describes an effort to develop and evaluate a questionnaire that assesses habitual sleep; behaviors associated with sleep and potential sleep problems; sleep hygiene; social and environmental determinants of sleep; beliefs and attitudes about sleep as it relates to health, safety, and functioning; and knowledge about sleep. A total of 124 participants completed the final questionnaire. Overall, the questionnaire and subscales demonstrated moderate internal consistency, and concurrent and divergent validity were demonstrated by comparing various subscales to existing measures. Future studies may utilize the descriptive data to determine the role of behavioral, social, and environmental determinants of healthy sleep.

Environmental noise pollution in the United States: developing an effective public health response

BACKGROUND

Tens of millions of Americans suffer from a range of adverse health outcomes due to noise exposure, including heart disease and hearing loss. Reducing environmental noise pollution is achievable and consistent with national prevention goals, yet there is no national plan to reduce environmental noise pollution.

OBJECTIVES

We aimed to describe some of the most serious health effects associated with noise, summarize exposures from several highly prevalent noise sources based on published estimates as well as extrapolations made using these estimates, and lay out proven mechanisms and strategies to reduce noise by incorporating scientific insight and technological innovations into existing public health infrastructure.

DISCUSSION

We estimated that 104 million individuals had annual LEQ(24) levels > 70 dBA (equivalent to a continuous average exposure level of >70 dBA over 24 hr) in 2013 and were at risk of noise-induced hearing loss. Tens of millions more may be at risk of heart disease, and other noise-related health effects. Direct regulation, altering the informational environment, and altering the built environment are the least costly, most logistically feasible, and most effective noise reduction interventions.

CONCLUSION

Significant public health benefit can be achieved by integrating interventions that reduce environmental noise levels and exposures into the federal public health agenda.

Dissecting the impact of sleep and stress on the cortisol awakening response in young adults

Cortisol rises precipitously upon awakening, in what has been called the cortisol awakening response (CAR). Atypical CARs have been linked to a number of negative health outcomes. Yet, our understanding of the possible mechanisms creating these associations remains unclear. Both stress and sleep can influence CAR, and may potentially explain its links to health. However, these factors also impact each other, and their influence on CAR has rarely been studied simultaneously. In order to differentiate their effects, this study examined the impact of daily life hassles, anticipatory stress, and subjectively reported sleep on CAR among 58 college students. Self-reported stress and sleep, as well as salivary cortisol (collected during the first hour after awakening) were obtained across two consecutive days. Total sleep time predicted CAR magnitude, but daily hassles and anticipatory stress did not after accounting for the effect of sleep. Lower total sleep time was associated with lower awakening cortisol and greater CAR. These results provide further evidence for the impact of sleep insufficiency on CAR, and suggest future efforts to use CAR as a stress biomarker should take the impact of sleep into consideration.

Pericytes: brain-immune interface modulators

The premise that the central nervous system is immune-privileged arose from the fact that direct contact between immune and nervous cells is hindered by the blood-brain barrier. However, the blood-brain barrier also comprises the interface between the immune and nervous systems by secreting chemo-attractant molecules and by modulating immune cell entry into the brain. The majority of published studies on the blood-brain barrier focus on endothelial cells (ECs), which are a critical component, but not the only one; other cellular components include astroglia, microglia, and pericytes. Pericytes are poorly studied in comparison with astrocytes or ECs; they are mesenchymal cells that can modify their ultrastructure and gene expression in response to changes in the central nervous system microenvironment. Pericytes have a unique synergistic relationship with brain ECs in the regulation of capillary permeability through secretion of cytokines, chemokines, nitric oxide, matrix metalloproteinases, and by means of capillary contraction. Those pericyte manifestations are related to changes in blood-brain barrier permeability by an increase in endocytosis-mediated transport and by tight junction disruption. In addition, recent reports demonstrate that pericytes control the migration of leukocytes in response to inflammatory mediators by up-regulating the expression of adhesion molecules and releasing chemo-attractants; however, under physiological conditions they appear to be immune-suppressors. Better understanding of the immune properties of pericytes and their participation in the effects of brain infections, neurodegenerative diseases, and sleep loss will be achieved by analyzing pericyte ultrastructure, capillary coverage, and protein expression. That knowledge may provide a mechanism by which pericytes participate in the maintenance of the proper function of the brain-immune interface.

The role of sleep in human declarative memory consolidation

Through a variety of methods, researchers have begun unraveling the mystery of why humans spend one-third of their lives asleep. Though sleep likely serves multiple functions, it has become clear that the sleeping brain offers an ideal environment for solidifying newly learned information in the brain. Sleep , which comprises a complex collection of brain states, supports the consolidation of many different types of information. It not only promotes learning and memory stabilization, but also memory reorganization that can lead to various forms of insightful behavior. As this chapter will describe, research provides ample support for these crucial cognitive functions of sleep . Focusing on the declarative memory system in humans, we review the literature regarding the benefits of sleep for both neutral and emotionally salient declarative memory. Finally, we discuss the literature regarding the impact of sleep on emotion regulation.

Fatigue on the flight deck: the consequences of sleep loss and the benefits of napping

The detrimental effects of fatigue in aviation are well established, as evidenced by both the number of fatigue-related mishaps and numerous studies which have found that most pilots experience a deterioration in cognitive performance as well as increased stress during the course of a flight. Further, due to the nature of the average pilot's work schedule, with frequent changes in duty schedule, early morning starts, and extended duty periods, fatigue may be impossible to avoid. Thus, it is critical that fatigue countermeasures be available which can help to combat the often overwhelming effects of sleep loss or sleep disruption. While stimulants such as caffeine are typically effective at maintaining alertness and performance, such countermeasures do nothing to address the actual source of fatigue - insufficient sleep. Consequently, strategic naps are considered an efficacious means of maintaining performance while also reducing the individual's sleep debt. These types of naps have been advocated for pilots in particular, as opportunities to sleep either in the designated rest facilities or on the flight deck may be beneficial in reducing both the performance and alertness impairments associated with fatigue, as well as the subjective feelings of sleepiness. Evidence suggests that strategic naps can reduce subjective feelings of fatigue and improve performance and alertness. Despite some contraindications to implementing strategic naps while on duty, such as sleep inertia experienced upon awakening, both researchers and pilots agree that the benefits associated with these naps far outweigh the potential risks. This article is a literature review detailing both the health and safety concerns of fatigue among commercial pilots as well as benefits and risks associated with strategic napping to alleviate this fatigue.

Hours of sleep in adolescents and its association with anxiety, emotional concerns, and suicidal ideation

OBJECTIVES

Anxiety and concerns in daily life may result in sleep problems and consistent evidence suggests that inadequate sleep has several negative consequences on cognitive performance, physical activity, and health. The aim of our study was to evaluate the association between mean hours of sleep per night, psychologic distress, and behavioral concerns.

METHODS

A cross-sectional analysis of the correlation between the number of hours of sleep per night and the Zung Self-rating Anxiety Scale (Z-SAS), the Paykel Suicidal Scale (PSS), and the Strengths and Difficulties Questionnaire (SDQ), was performed on 11,788 pupils (mean age±standard deviation [SD], 14.9±0.9; 55.8% girls) from 11 different European countries enrolled in the SEYLE (Saving and Empowering Young Lives in Europe) project.

RESULTS

The mean number of reported hours of sleep per night during school days was 7.7 (SD, ±1.3), with moderate differences across countries (r=0.06; P<.001). A reduced number of sleeping hours (less than the average) was more common in girls (β=0.10 controlling for age) and older pupils (β=0.10 controlling for sex). Reduced sleep was found to be associated with increased scores on SDQ subscales of emotional (β=-0.13) and peer-related problems (β=-0.06), conduct (β=-0.07), total SDQ score (β=-0.07), anxiety (Z-SAS scores, β=-10), and suicidal ideation (PSS, β=-0.16). In a multivariate model including all significant variables, older age, emotional and peer-related problems, and suicidal ideation were the variables most strongly associated with reduced sleep hours, though female gender, conduct problems measured by the SDQ, and anxiety only showed modest effects (β=0.03-0.04).

CONCLUSIONS

Our study supports evidence that reduced hours of sleep are associated with potentially severe mental health problems in adolescents. Because sleep problems are common among adolescents partly due to maturational processes and changes in sleep patterns, parents, other adults, and adolescents should pay more attention to their sleep patterns and implement interventions, if needed.