Rapid Eye Movement Sleep, Sleep Continuity and Slow Wave Sleep as Predictors of Cognition, Mood, and Subjective Sleep Quality in Healthy Men and Women, Aged 20–84 Years
«Sleep and its sub-states are assumed to be important for brain function across the lifespan but which aspects of sleep associate with various aspects of cognition, mood and self-reported sleep quality has not yet been established in detail. Sleep was quantified by polysomnography, quantitative Electro-Encephalo-Gram (EEG) analysis and self-report in 206 healthy men and women, aged 20-84 years, without sleep complaints. Waking brain function was quantified by five assessments scheduled across the day covering objectively assessed performance across cognitive domains including sustained attention and arousal, decision and response time, motor and sequence control, working memory, and executive function as well as self-reports of alertness, mood and affect. Controlled for age and sex, self-reported sleep quality was negatively associated with number of awakenings and positively associated with the duration of Rapid-Eye-Movement (REM) sleep, but nosignificantassociations with Slow Wave Sleep (SWS) measures were observed. Controlling only for age shows that associations between objective and subjective sleep quality were much stronger in women than in men. Analysis of 51 performance measures demonstrated that after controlling for age and sex, fewer awakenings and more REM sleep were associatedsignificantly with better performance on the Goal Neglect task, which is a test of executive function. Factor analysis of the individual performance measures identified four latent variables labelled Mood/Arousal, Response Time, Accuracy and Visual Perceptual Sensitivity. Whereas Mood/Arousal improved with age, Response Times became slower, while Accuracy and Visual perceptual sensitivity showed little change with age. After controlling for sex and age, nominally significantassociation between sleep and factor scores were observed such that Response Times were faster with more SWS, and Accuracy was reduced where individuals woke more often or had less REM sleep. These data identify a positive contribution of SWS to processing speed and in particular highlight the importance of sleep continuity and REM sleep for subjective sleep quality and performance accuracy across the adult lifespan. These findings warrant further investigation of the contribution of sleep continuity and REM sleep to brain function.»
The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature.
«A systematic review was conducted using Samueli Institute's Rapid Evidence Assessment of the Literature (REAL) process to determine the evidence base for melatonin as an agent to optimize sleep or improve sleep quality, and generalize the results to a military, civilian, or other healthy, active, adult population. Multiple databases were searched yielding 35 randomized controlled trials (RCTs) meeting the review's inclusion criteria, which were assessed for methodological quality as well as for melatonin effectiveness. The majority of included studies were high quality (83.0%). Overall, according to Grading Recommendations, Assessment Development and Evaluation (GRADE) methodology, weak recommendations were made for preventing phase shifts from jet lag, for improving insomnia in both healthy volunteers and individuals with a history of insomnia, and for initiating sleep and/or improving sleep efficacy. Based on the literature to date, no recommendations for use in shift workers or to improve hormonal phase shift changes in healthy people can be made at this time. Larger and longer-duration RCTs utilizing well characterized products areneeded to warrant melatonin recommendations in young, healthy adults.»
The effects of bedroom air quality on sleep and next-day performance.
«The effects of bedroom air quality on sleep and next-day performance were examined in two field-intervention experiments in single-occupancy student dormitory rooms. The occupants, half of them women, could adjust an electric heater to maintain thermal comfort but they experienced two bedroom ventilation conditions, each maintained for 1 week, in balanced order. In the initial pilot experiment (N = 14), bedroom ventilation was changed by opening a window (the resulting average CO2 level was 2585 or 660 ppm). In the second experiment (N = 16), an inaudible fan in the air intake vent was either disabled or operated whenever CO2 levels exceeded 900 ppm (the resulting average CO2 level was 2395 or 835 ppm). Bedroom air temperatures varied over a wide range but did not differ between ventilation conditions. Sleep was assessed from movement data recorded on wristwatch-type actigraphs and subjects reported their perceptions and their well-being each morning using online questionnaires. Two tests of next-day mental performance were applied. Objectively measured sleep quality and the perceived freshness of bedroom air improvedsignificantly when the CO2 level was lower, as did next-day reported sleepiness and ability to concentrate and the subjects' performance of a test of logical thinking.»
Effect of the use of earplugs and eye mask on the quality of sleep in intensive care patients: a systematic review.
«Intensive care unit (ICU) environment has a very strong and unavoidable negative impact on patients' sleep. Sleep deprivation in ICU patients has been already studied and negative effects on their outcome (prolonged ICU stay, decreased recovery) and complication rates (incidence of delirium, neuropsychological sequels of critical illness) discussed. Several interventions potentially improving the sleep disturbance in ICU (sleep-promotion strategies) have been assumed and tested for clinical practice. We present a review of recent literature focused on chosen types of non-pharmacological interventions (earplugs and eye mask) analysing their effect on sleep quality/quantity. From the total amount of 82 papers found in biomedical databases (CINAHL, PubMed and SCOPUS) we included the 19 most eligible studies meeting defined inclusion/exclusion criteria involving 1 379 participants. Both experimental and clinical trials, either ICU and non-ICU patient populations were analysed in the review. Most of the reviewed studies showed a significant improvement of subjective sleep quality when using described non-pharmacological interventions (objective parameters were not significantly validated). Measuring the sleep quality is a major concern limiting the objective comparison of the studies' results since non-standardised (and mainly individual) tools for sleep quality assessment were used. Despite the heterogeneity of analysed studies and some common methodological issues (sample size, design, outcome parameters choice and comparison) earplugs and eye mask showed potential positive effects on sleep quality and the incidence of delirium in ICU patients.»
The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: a systematic review of the liter...
«RESULTS: Three studies (with 136 participants) met our inclusion criteria; these had limitations in study design and/or implementation. One study compared the effect of BB lenses with clear lenses on contrast sensitivity (CS) and colour vision (CV) using a pseudo-RCT crossover design; there was no observed difference between lens types (log CS; Mean Difference (MD) = -0.01 [-0.03, 0.01], CV total error score on 100-hue; MD = 1.30 [-7.84, 10.44]). Another study measured critical fusion frequency (CFF), as a proxy for eye fatigue, on wearers of low and high BB lenses, pre- and post- a two-hour computer task. There was no observed difference between low BB and standard lens groups, but there was a less negative change in CFF between the high and low BB groups (MD = 1.81 [0.57, 3.05]). Both studies compared eyestrain symptoms with Likert scales. There was no evidence of inter-group differences for either low BB (MD = 0.00 [-0.22, 0.22]) or high BB lenses (MD = -0.05 [-0.31, 0.21]), nor evidence of a difference in the proportion of participants showing an improvement in symptoms of eyestrain or eye fatigue. One study reported a small improvement in sleep quality in people with self-reported insomnia after wearing high compared to low-BB lenses (MD = 0.80 [0.17, 1.43]) using a 10-point Likert scale. A study involving normal participants found no observed difference in sleep quality. We found no studies investigating effects on macular structure or function.
CONCLUSIONS: We find a lack of high quality evidence to support using BB spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.»
Effect of crocetin on quality of sleep: A randomized, double-blind, placebo-controlled, crossover study.
«RESULTS: Delta power was significantlyincreased with crocetin compared with placebo. There were nosignificant differences in the other sleep parameters, including sleep latency, sleep efficiency, total sleep time, and wake after sleep onset. Subjective scores for sleepiness on rising and feeling refreshed were significantlyimproved with crocetin compared with placebo.
CONCLUSIONS: The findings of the present study suggest that crocetinsupplementation contributes to sleep maintenance, leading to improved subjective sleep quality.»
Therapeutic efficacy and safety of chamomile for state anxiety, generalized anxiety disorder, insomnia, and sleep quality: A systematic review and ...
«This systematic review and meta-analysis aimed to study the efficacy and safety of chamomile for the treatment of state anxiety, generalized anxiety disorders (GADs), sleep quality, and insomnia in human. Eleven databases including PubMed, Science Direct, Cochrane Central, and Scopus were searched to retrieve relevant randomized control trials (RCTs), and 12 RCTs were included. Random effect meta-analysis was performed by meta package of R statistical software version 3.4.3 and RevMan version 5.3. Our meta-analysis of three RCTs did not show any difference in case of anxiety (standardized mean difference = -0.15, 95% CI [-0.46, 0.16], P = 0.4214). Moreover, there is only one RCT that evaluated the effect of chamomile on insomnia and it found nosignificant change in insomnia severity index (P > 0.05). By using HAM-A scale, there was a significant improvement in GAD after 2 and 4 weeks of treatment (mean difference = -1.43, 95% CI [-2.47, -0.39], P = 0.007), (MD = -1.79, 95% CI [-3.14, -0.43], P = 0.0097), respectively. Noteworthy, our meta-analysis showed a significant improvement in sleep quality after chamomile administration (standardized mean difference = -0.73, 95% CI [-1.23, -0.23], P < 0.005). Mild adverse events were only reported by three RCTs. Chamomile appears to be efficacious and safe for sleep quality and GAD. Little evidence is there to show its effect on anxiety and insomnia. Larger RCTs areneeded to ascertain these findings.»
Perceived Stress and Sleep Quality in Midlife and Later: Controlling for Genetic and Environmental Influences.
«Objective/Background: Stress is a strong predictor for poor sleep quality. However, little is known about the mechanism of this association or the respective contribution of genetic and environmental factors. This study aims to investigate general distress as a mediator and cognitive/emotional control as a moderator in the stress-sleep relationship and estimate the influence of gene and environment in this mechanism using a national representative sample. Participants: 1,255 middle-aged and elderly Americans and a subset of 296 twins. Methods: The Pittsburgh Sleep Quality Index, the Perceived Stress Scale, the Mood and Anxiety Symptom Questionnaire and the Self-Control Scale assessed sleep quality, perceived stress, general distress, and emotional/cognitive control. Structural equation modeling was used to test the mediating and moderating effect. ACE models on MZ and DZ twins were used to separate the contribution of genetic and environmental factors. Finally, a co-twin design was nested in the SEM to control for the genetic and familial confounds in the stress-sleep relationship. Results: General distress mediated the relationship between stress and sleep while emotional/cognitive control buffered the impact of stress on general distress. 7.69% of the variance in sleep quality was explained by genetic and familial factors and 8.26% was explained by individual-specific factors. Emotional/cognitive control only moderated the individual-specific association between stress and sleep. Conclusions: Gene/family factors and individual factors explained an equivalent proportion of the stress-sleep relationship. The genetic and familial association between stress and sleep is more robust, whereas the individual-specific association can be buffered by regulation strategies.»
Sleep quality in cigarette smokers and nonsmokers: findings from the general population in central China.
«RESULTS: Significantly more smokers than nonsmokers demonstrated poor sleep quality and sleep disturbances. Among smokers, linear regression analyses showed that poor sleep was inversely associated with cigarettes per day, and positively associated with years of smoking, quit attempts, and smoking craving. Logistic regression analysis showed that quit attempts and smoking cravings were associated with higher odds of sleep disturbances.
CONCLUSIONS: Sleep disturbances were more prevalent among cigarette smokers than nonsmokers. Smokers also varied in sleep problems on the basis of the characteristics of their smoking. Smokers should be informed about the link between cigarette smoking and poor sleep quality, and should be advised that one of several important health benefits from smoking cessation could be the improvement of sleep quality. Sleep therapy should be recommended as an adjunctive treatment for smoking cessation.»
The serotonin transporter gene-linked polymorphic region (5-HTTLPR) and the sleep-promoting effects of tryptophan: A randomized placebo-controlled ...
«RESULTS: The results support the sleep-promoting effects of tryptophan. Tryptophanimproved objective sleep efficiency and objective wake after sleep onset irrespective of allelic variation. There was a marginally significant improvement of subjective sleep quality in the 5-HTTLPR S-allele group but not in the L-allele group following tryptophanrelative to placebo intake. In contrast, a significantly poorer sleep quality in the S-allele as opposed to the L-allele group in the placebo condition was not observed in the tryptophan condition.
CONCLUSIONS: Tryptophan augmentation promises to be a valuable treatment strategy for sleep impairments related to genetic deficiencies in 5-HT functioning.»
The Relationship Between Sleep Quality and Internet Addiction Among Female College Students.
«RESULTS: In total, 503 female students were recruited (mean age 17.05 ± 1.34). After controlling for age, body mass index, smoking and drinking habits, religion, and habitual use of smartphone before sleep, internet addiction was found to be significantlyassociated with subjective sleep quality, sleep latency, sleep duration, sleep disturbance, use of sleep medication, and daytime dysfunction. Worse quality of sleep as reflected by PSQI was noted in students with moderate and severe degrees of internet addiction compared to those with mild or nointernet addiction. Logistic regression analysis of the association between scores on IAT and sleep quality, demonstrated significantcorrelations between quality of sleep and total IAT scores (odds ratio = 1.05:1.03 ∼ 1.06, p < 0.01).
CONCLUSION: The results of this study demonstrated significant negative association between the degree of internet addiction and sleep quality, providing reference for educational institutes to minimize adverse effects associated with internet use and improve students' sleep quality.»
A Double-Blind, Randomized, Placebo-Controlled Crossover Clinical Study of the Effects of Alpha-s1 Casein Hydrolysate on Sleep Disturbance.
«This study evaluated the effects of alpha-s1 casein hydrolysate (ACH; Lactium®) on the subjective and objective sleep profiles of a community-based sample of Koreans with poor sleep quality. We performed a double-blind, randomized crossover trial with 48 participants (49.0 ± 1.7 years old, 65% female) who exhibited a mild to moderate degree of sleep disturbance. Either ACH or placebo was administered for the initial four weeks, and the counterpart was administered in precisely the same manner after a four-week washout period. Sleep disturbance scales, daytime functioning, and psychiatric aspects showed a similar tendency to improve during both ACH and placebo phases without significant group differences. Overall perceived sleep profiles in sleep diaries were significantlyimproved during the ACH phase, represented by increased total sleep time and sleep efficiency (SE), as well as decreasedsleep latency and wake after sleep onset (WASO). Interestingly, actigraphy demonstrated significantlyincreased SE after continuous use of ACH for four weeks, clearly more improved when compared to two weeks of use. The polysomnography measures showed a similar tendency without statistically significant group differences. Our findings suggest that refined ACH was well tolerated and could improve sleep quality, with possible cumulative beneficial effects with long-term administration.»
Association of serum 25-hydroxyvitamin D concentrations with sleep phenotypes in a German community sample.
«RESULTS: The regression models revealed significantassociations of serum 25(OH)D concentration with night sleep duration and midsleep time. Noassociation was found for total sleep duration and night sleep efficiency. Higher serum 25(OH)D concentration was further associated with shorter WASO in males but longer WASO in females. Moreover, serum 25(OH)D concentration did not show any significantassociation with subjective sleep quality and daytime sleepiness.
CONCLUSION: The results indicate that a higher concentration of serum 25(OH)D is associated with longer and earlier night sleep. Although the present study was able to demonstrate an association between serum 25(OH)D concentration and objective sleep parameters, no conclusion about underlying mechanisms or causal inferences can be drawn.»
Sleep- and Wake-Promoting Drugs: Where Are They Being Sourced, and What Is Their Impact?
«Background: Recent decades have seen both an increased number of shift workers in order to deliver services 24/7, and increased potential for social interactions at all hours of the day. People have sought to engage in strategies, which either promote vigilance or facilitate sleep, with the use of sleep- and wake-promoting drugs representing one strategy. Methods: We investigated use of sleep- and wake-promoting drugs in participants (n = 377) who completed a survey investigating the type and source of sleep- and wake-promoting drugs, and their impact on sleep and performance outcomes. Results: The most commonly reported wake-promoting drugs were amphetamine and dextroamphetamin salts, modafinil, and illicit substances including methamphetamine and cocaine, while the most commonly reported sleep-promoting drugs were benzodiazepine and antihistamines. Use of a sleep-promoting drug in the past month was associated with higher odds of having poorer sleep quality (OR = 3.15) and moderate-high insomnia (OR = 3.30), while use of a wake-promoting drug was associated with poor sleep quality (OR = 3.76), or making a fatigue-related error (OR = 2.65). Conclusions: These findings represent novel data on the use and source of sleep- and wake-promoting- drugs, and suggest that despite their use, poor sleep and performance outcomes persist, likely representing individuals struggling to keep up with the 24/7 world.»