Changes In Sleep Time Research Articles

A longitudinal observational population-based study of brain volume associated with changes in sleep timing from middle to late-life.

Sleep behaviors are related to brain structure and function, but the impact of long-term changes in sleep timing on brain health has not been clearly addressed. The purpose of this study was to examine the association of longitudinal changes in sleep timing from middle to late-life with gray matter volume (GMV), an important marker of brain aging. We enrolled 1798 adults (aged 49-82 years, men 54.6%) who underwent magnetic resonance imaging (MRI) between 2011 and 2014. Midsleep time (MST) on free days corrected for sleep debt on workdays was adopted as a marker of sleep timing. Data on MST were available at the time of MRI assessment and at examinations that were given 9 years earlier (2003-2004). Longitudinal changes in MST over the 9-year period were derived and categorized into quartiles. Subjects in quartile 1 were defined as "advancers" (MST advanced ≥ 1 h) while those in quartile 4 were defined as "delayers" (MST delayed ≥ 0.2 h). Quartiles 2-3 defined a reference group (MST change was considered modest). The relationship of GMV with MST changes over 9 years was investigated. Nine-year change in MST were significantly associated with GMV. Compared to the reference group, advancers had smaller GMVs in the frontal and temporal regions. A delay in MST was also associated with smaller cerebellar GMV. In middle-to-late adulthood, the direction of change in MST is associated with GMV. While advancers and delayers in MST tend to present lower GMV, associations appear to differ across brain regions.

Is Covid-19 lockdown related to an increase of accesses for seizures in the emergency department? An observational analysis of a paediatric cohort in the Southern Italy

BackgroundThe World Health Organization (WHO) declared a global pandemic of Covid-19 on 11 March 2020. The lockdown caused a lifestyle changes: an increase in the use of mobile media devices (MMDs), sleep and psychiatric disorders, incorrect habits regarding food and physical activities.We investigate prevalence of admission for seizures at our emergency department (ED), during Italian lockdown, comparing with that of the same period of the previous year (2019), and the relationship with some lifestyle changes.MethodsIn this observational study, patients (4–14 years) with seizures that accessed at our ED, during Italian lockdown, were eligible. Non-epileptic events and febrile seizures were excluded. We describe two groups: patients with new-onset seizures and not. Moreover, a questionnaire concerning use of MMDs and sleep habits was administered.ResultsFifty-seven patients were included; median age 8.03 years. Considering only paediatric medical emergencies, the prevalence of accesses for seizures was 2.6% (CI 95% 0.020–0.034), while the incidence was 0.94% (CI 95% 0.006–0.0149). There was a statistically significant difference with prevalence of previous years, χ2 102.21 (p = 0.0001). We also reported a difference in daily screen time (DST) (p = 0.001) and total sleep time (TST) (p = 0.045), in all population, between period pre- and during lockdown. A negative correlation between DST and seizures latency (Spearman’s ρ -0.426, p = 0.038) was found. In the two groups, the results were partially overlapping.ConclusionsDuring lockdown period, we assisted to an increase of accesses for seizures. It is conceivable that a sleep time change and/or higher MMD use could act as triggers for seizures.

Association of Delaying School Start Time With Sleep Duration, Timing, and Quality Among Adolescents

Sleep is a resource that has been associated with health and well-being; however, sleep insufficiency is common among adolescents. To examine how delaying school start time is associated with objectively assessed sleep duration, timing, and quality in a cohort of adolescents. This observational cohort study took advantage of district-initiated modifications in the starting times of 5 public high schools in the metropolitan area of Minneapolis and St Paul, Minnesota. A total of 455 students were followed up from grade 9 (May 3 to June 3, 2016) through grade 11 (March 15 to May 21, 2018). Data were analyzed from February 1 to July 24, 2019. All 5 participating schools started early (7:30 am or 7:45 am) at baseline (2016). At follow-up 1 (2017) and continuing through follow-up 2 (2018), 2 schools delayed their start times by 50 and 65 minutes, whereas 3 comparison schools started at 7:30 am throughout the observation period. Wrist actigraphy was used to derive indices of sleep duration, timing, and quality. With a difference-in-difference design, linear mixed-effects models were used to estimate differences in changes in sleep time between delayed-start and comparison schools. A total of 455 students were included in the analysis (among those identifying sex, 225 girls [49.5%] and 219 boys [48.1%]; mean [SD] age at baseline, 15.2 [0.3] years). Relative to the change observed in the comparison schools, students who attended delayed-start schools had an additional mean 41 (95% CI, 25-57) objectively measured minutes of night sleep at follow-up 1 and 43 (95% CI, 25-61) at follow-up 2. Delayed start times were not associated with falling asleep later on school nights at follow-ups, and students attending these schools had a mean difference-in-differences change in weekend night sleep of -24 (95% CI, -51 to 2) minutes from baseline to follow-up 1 and -34 (95% CI, -65 to -3) minutes from baseline to follow-up 2, relative to comparison school participants. Differences in differences for school night sleep onset, weekend sleep onset latency, sleep midpoints, sleep efficiency, and the sleep fragmentation index between the 2 conditions were minimal. This study found that delaying high school start times could extend adolescent school night sleep duration and lessen their need for catch-up sleep on weekends. These findings suggest that later start times could be a durable strategy for addressing population-wide adolescent sleep deficits.

Sleep Regularity Index in Patients with Alcohol Dependence: Daytime Napping and Mood Disorders as Correlates of Interest.

Alcohol use disorder (AUD) is often accompanied by comorbid conditions, including sleep disturbances related to sleep regularity and timing. The Sleep Regularity Index (SRI) is a novel measure that assesses the probability that an individual is awake (vs. asleep) at any two time points 24 h apart. We calculated actigraphy-based SRI on 124 participants with alcohol dependence to capture the effects of changes in sleep timing and duration among patients enrolled in an inpatient alcohol treatment program. During the course of the study, the mean SRI increased between weeks 1 and 3 (75.4 to 77.8), thus indicating slightly improved sleep quality and regularity during alcohol treatment. Individuals within the bottom quartile of SRI scores at week 1 improved significantly over time. Average total SRI for individuals with no mood disorders was slightly higher than that for individuals with one or more mood disorders. Increased SRI scores were associated with lower total nap duration from week 1 to week 3. Increased SRI scores were associated with decreased mental/physical exhaustion scores from week 1 to week 3. The SRI could be a target for assessment/intervention in certain sub-groups of individuals undergoing inpatient treatment for AUD.

Effects of Tai Chi Intervention on Perceived Stress, Anxiety, and Sleep in College Students

Background: Previous studies on effects of Tai Chi on physical and mental health among college students have lacked an objective measure of sleep quality. This study will address the gaps in the current literature. Purpose: This study examined the effects of 16-week Tai Chi lessons on perceived stress, anxiety, and sleep quality measured with the ActiGraph activity monitor in college students. Methods: Participants were forty-five college students (14 males and 31 females) with mean age of 19 yrs. (SD = 0.548 yrs.) who enrolled in one, 90-min Tai Chi lesson per week for 16 weeks during a fall semester of 2016 at one major public university in Shanghai, China. One week prior to and after the 16-week Tai Chi lessons, the students completed the Perceived Stress Scale (PSS), the Generalized Anxiety Disorder 7-item (GAD-7) Scale. In addition, they wore the ActiGraph Gt3X-BT activity monitor day and night for seven consecutive days to objectively measure their sleep time and quality. Results: The paired t-tests showed no significant changes in the perceived stress and anxiety from the pre- to the post-test (t = -0.429, df = 37, p = 0.670; t = -1.605, df = 37, p = 0.117). The ANOVA with repeated measures revealed no significant main effect of gender, time, and the interaction of them in the perceived stress and anxiety. The paired t-test yielded a significant change in sleep time (t = 2.48, df = 37, p = 0.017). There was no significant main effect of gender and the interaction of time with gender. The paired t-test showed no significant differences in sleep quality over times. Conclusion: Learning and performing one, 90-min Tai Chi lesson weekly for 16 weeks helped the students maintain a manageable level of the perceived stress and anxiety and meet the recommended sleep time and to have a high level of sleep quality while experiencing a moderate level of stress and anxiety over times.

Later Bedtimes Predict Prospective Increases in Symptom Severity in Individuals with Obsessive Compulsive Disorder (OCD): An Initial Study

ABSTRACT Prior studies of sleep in individuals with OCD have often focused on sleep duration. Several studies have found that individuals with OCD sleep less than healthy controls while others have failed to find significant group differences. Addressing sleep timing has been much more rare, but have consistently shown that many individuals with severe OCD in inpatient facilities had markedly elevated rates of disruptions in sleep timing. We extend prior work by testing prospective relations between sleep and OC symptoms in individuals representing a range of OC symptom severity. Twenty-six individuals diagnosed with OCD, 18 healthy controls, and 10 with subthreshold OC symptoms, completed seven days of sleep diaries and OCD symptom ratings. Results showed that sleep timing (later bedtimes) predicted prospective increases in both obsessions and compulsions in individuals with OCD but not the other two groups. In contrast, there were no significant effects of sleep duration. The significant effects of sleep timing in the OCD group were maintained controlling for depressive symptoms and OCD symptoms did not predict prospective changes in sleep timing. In conclusion, there is increasing evidence that sleep timing may play an important role in OCD and additional work in this area is encouraged.

Association of postprandial triglyceride responses with insulin resistance among rotational night shift healthcare workers.

What is the central question of this study? Does long-term rotational night shift work among healthcare workers alter postprandial triglyceride metabolism, and are the postprandial triglyceride responses associated with insulin resistance? What is the main finding and its importance? Rotational night shift duties in healthcare workers might have a negative impact on postprandial triglyceride responses and insulin sensitivity. This is the first study in which postprandial triglyceride responses among shift workers exposed to long-term night shifts have been studied. Studies on the postprandial period demonstrate that in experimental conditions, abrupt or acute changes in sleep timing and work are followed by significantly altered postprandial glucose, insulin secretion and lipid tolerance. Whether shift work results in altered postprandial triglyceride (PPTG) metabolism in the long term is not known. In the present study, we aimed to ascertain the association between PPTG and shift work in relationship to cardiometabolic risks and to compare the PPTG response among healthcare workers with and without night shift duties. Twenty healthcare workers with rotational night shifts (group2) and 20 age- and sex-matched healthcare workers who had not done night shift duty in the past 1year or ever (group1) were recruited. Only subjects with normal glucose tolerance were recruited. A standardized fat challenge test was done in all study subjects. The postprandial triglyceride area under the curve (PPTG AUC) showed overall (n=40) a significant positive correlation with fasting insulin and homeostatic model assessment of insulin resistance (HOMA-IR) (r=0.40, P=0.01 and r=0.37, P=0.01, respectively) and in group2 (r=0.49, P=0.02 and r=0.44, P=0.042, respectively). The PPTG peak also showed a significant positive correlation with fasting insulin and HOMA-IR in group2 (r=0.52, P=0.01 and r=0.47, P=0.03, respectively). No significant correlation was found in group1. The PPTG AUC and PPTG peak were, however, comparable between both groups. The findings of this pilot study suggest that rotational night shift duties in healthcare workers might have a negative impact on metabolic parameters, including postprandial triglyceride responses and insulin sensitivity.

Sleep differences in the UK between 1974 and 2015: Insights from detailed time diaries.

It is often stated that sleep deprivation is on the rise, with work suggested as a main cause. However, the evidence for increasing sleep deprivation comes from surveys using habitual sleep questions. An alternative source of information regarding sleep behaviour is time‐use studies. This paper investigates changes in sleep time in the UK using the two British time‐use studies that allow measuring “time in bed not asleep” separately from “actual sleep time”. Based upon the studies presented here, people in the UK sleep today 43 min more than they did in the 1970s because they go to bed earlier (~30 min) and they wake up later (~15 min). The change in sleep duration is driven by night sleep and it is homogeneously distributed across the week. The former results apply to men and women alike, and to individuals of all ages and employment status, including employed individuals, the presumed major victims of the sleep deprivation epidemic and the 24/7 society. In fact, employed individuals have experienced a reduction in short sleeping of almost 4 percentage points, from 14.9% to 11.0%. There has also been a reduction of 15 percentage points in the amount of conflict between workers work time and their sleep time, as measured by the proportion of workers that do some work within their “ideal sleep window” (as defined by their own chronotype).

RETRACTED ARTICLE: A mathematical model to study the relationship between the dietary profiles, core body temperature and sleep profile in the high school students

Body temperature (Tb), food intake and sleep cycle follows a circadian rhythm. Circadian variations of Tb may be influenced by changes in sleep time, late night consumption of high calorie diet and less physical activities. Deviations in any of these daily habits may alter the acrophase, mesor and amplitude of the cosinor curve of Tb. Changes in these confounding factors may also contribute to the body mass index (BMI) of the individual. This study was conducted on 29 high school going adolescents. We have employed an ideal cosinor model to study the changes in the 24 h cyclical changes in Tb (n = 12). Academic overload during examination days was seen in these high school going adults. Sleep duration and dietary habits were also studied in them to find out the relationship with BMI and circadian variations if any (n = 17). Higher BMI was observed in individuals having shorter sleep duration. BMI was high in students consuming high calorie diet at the time of the day when the body metabolism is normally low. A mathematical model exhibiting altered circadian rhythms is proposed that may be used to modify strategies to restore biorhythms for better health.

Does a change in sleep timing increase testosterone in young adult men?

Men are more evening oriented than women. These sex difference might be a result of gonadal hormones, especially of testosterone. Here, we tested for a causal relationship by shifting the sleep timing of young men to one hour later and assessed the influence on saliva testosterone. 50 men participated in our study (31 experimental, 19 control group). Sleep timing was measured with actigraphy. One week served as baseline and afterwards, participants were randomly assigned to either the control or the experimental group. In the experimental group, men were asked to go to bed about one hour later and to sleep one hour longer in the morning. Participants in the control group experienced no significant changes in sleep timing. In the experimental group, participants went to bed later and woke up later; therefore, mid-point of sleep was shifted to a later time and sleep duration decreased, because he men went to bed about one hour later but woke up only about 30 min later. The control group experienced a decline in testosterone, but the experimental group not. Changes in mid-point of sleep between baseline week and experimental week were correlated with the change in testosterone (r = 0.285).

Seasonal and weather variation of sleep and physical activity in 12–14-year-old children

ABSTRACT Background: Understanding variation in physical activity (PA) and sleep is necessary to develop novel intervention strategies targeting adolescents’ health behaviors. We examined the extent to which PA and sleep vary by aspects of the physical environment. Participants: We performed a cross-sectional analysis of 669 adolescents in the Project Viva cohort. Methods: We estimated total PA, sleep duration, sleep efficiency, and sleep midpoint timing from wrist accelerometers. We used multivariable linear regression models and generalized estimated equations to assess associations of PA and sleep with season and daily weather conditions obtained from the National Oceanic and Atmospheric Administration archive. Results: Mean age was 12.9 (SD 0.6) years; 51% were female and 68% were white. Mean sleep duration was 466 (SD 42) min per night and total PA was 1,652 (SD 431) counts per min per day. Sleep midpoint time was 41 (95% CI: 27 to 54) min later in summer, 28 (95% CI: −41 to −14) min earlier in spring, and 29 (95% CI: −43 to −15) min earlier in autumn compared to winter. Higher temperature and longer day length both were associated with small reductions of nightly sleep duration. Adolescents were less physically active during winter and on rainy and short sunlight days. There was an inverse U-shaped relationship between PA and mean temperature. Conclusions: Season was associated with large changes in sleep timing, and smaller changes in other sleep and PA measurements. Given the importance of sleep and circadian alignment, future health behavioral interventions may benefit by targeting “season-specific” interventions.

Effects of short-term quetiapine treatment on emotional processing, sleep and circadian rhythms

Quetiapine is an atypical antipsychotic that can stabilise mood from any index episode of bipolar disorder. This study investigated the effects of seven-day quetiapine administration on sleep, circadian rhythms and emotional processing in healthy volunteers. Twenty healthy volunteers received 150 mg quetiapine XL for seven nights and 20 matched controls received placebo. Sleep-wake actigraphy was completed for one week both pre-dose and during drug treatment. On Day 8, participants completed emotional processing tasks. Actigraphy revealed that quetiapine treatment increased sleep duration and efficiency, delayed final wake time and had a tendency to reduce within-day variability. There were no effects of quetiapine on subjective ratings of mood or energy. Quetiapine-treated participants showed diminished bias towards positive words and away from negative words during recognition memory. Quetiapine did not significantly affect facial expression recognition, emotional word categorisation, emotion-potentiated startle or emotional word/faces dot-probe vigilance reaction times. These changes in sleep timing and circadian rhythmicity in healthy volunteers may be relevant to quetiapine's therapeutic actions. Effects on emotional processing did not emulate the effects of antidepressants. The effects of quetiapine on sleep and circadian rhythms in patients with bipolar disorder merit further investigation to elucidate its mechanisms of action.

Aging and Circadian Rhythms.

Aging is associated with numerous changes, including changes in sleep timing, duration, and quality. The circadian timing system interacts with a sleep-wake homeostatic system to regulate human sleep, including sleep timing and structure. This article reviews key features of the human circadian timing system, age-related changes in the circadian timing system, and how those changes may contribute to the observed alterations in sleep.

Child and Adolescent Sleep Patterns and Early School Start Times: Recognizing the Role of the Pediatric Nurse

Child and Adolescent Sleep Patterns and Early School Start Times: Recognizing the Role of the Pediatric Nurse

Changes in Sleep Time and Sleep Quality across the Ovulatory Cycle as a Function of Fertility and Partner Attractiveness

Research suggests that near ovulation women tend to consume fewer calories and engage in more physical activity; they are judged to be more attractive, express greater preferences for masculine and symmetrical men, and experience increases in sexual desire for men other than their primary partners. Some of these cycle phase shifts are moderated by partner attractiveness and interpreted as strategic responses to women's current reproductive context. The present study investigated changes in sleep across the ovulatory cycle, based on the hypothesis that changes in sleep may reflect ancestral strategic shifts of time and energy toward reproductive activities. Participants completed a 32-day daily diary in which they recorded their sleep time and quality for each day, yielding over 1,000 observations of sleep time and quality. Results indicated that, when the probability of conception was high, women partnered with less attractive men slept more, while women with more attractive partners slept less.

Changes in Sleep Duration, Timing, and Quality as Children Transition to Kindergarten

Sleep can be seen as a biologically driven behavior shaped by cultural context. A “poor fit” occurs when contextual demands for the timing and duration sleep periods are incompatible with the underlying biology. Such contextual factors are well-known for adults, yet little is known of the contextual factors that shape young children's sleep health and to what degree such factors impact sleep duration, timing, and quality. This study attempted to identify how the transition to kindergarten was associated with changes in sleep timing, duration, and quality for children enrolled in preschool prior to attending kindergarten vs. those who were not. Wrist actigraphy in 38 5-year-old children was collected at three longitudinal points before and after the start of kindergarten. Our data suggested that the transition to kindergarten was associated with a reduction in weekday sleep (mostly due to lost napping) and an advance in the weekday nocturnal sleep period that was most pronounced for children not enrolled in preschool prior to kindergarten. These sleep changes paralleled objective and caregiver-reported data of increased sleep pressure that lasted well into the first month of kindergarten.

Delayed Sleep Phase Disorder in an Australian School-Based Sample of Adolescents

To establish the extent to which the developmental changes in sleep timing experienced by Australian adolescents meet the International Classification of Sleep Disorders (ICSD-2) diagnostic criteria for delayed sleep phase disorder (DSPD), and whether adolescents with DSPD engage in poorer lifestyle choices, and are more impaired compared to good sleeping adolescents. Three-hundred seventy-four Australian adolescents (mean age 15.6 years, SD 1.0) participants completed a 7-day sleep diary, wore wrist actigraphy, and completed a battery of questionnaires to assess DSPD criteria. The ICSD-2 criteria for DSPD were met by 1.1% (N = 4) of the adolescents sampled. The majority of adolescents (51.9%, N = 194) met one criterion, 14% (N = 52) of the adolescents met 2 criteria, while 33.2% (N = 124) did not fulfill any DSPD criteria. Despite having significantly delayed sleep timing, adolescents who met all criteria for DSPD reported similar lifestyle habits and daytime functioning. However, there were trends for greater alcohol and caffeine consumption, less sport participation, yet more time spent on extracurricular activities (i.e., learning to play a musical instruments for adolescents with DSPD. Despite the majority of adolescents reporting DSPD symptoms, only a small minority met full diagnostic criteria. Adolescents with DSPD reported similar lifestyle habits and daytime functioning to those with some or no symptoms. Future investigations of non-school-attending DSPD adolescents are needed to confirm the trends for lifestyle behaviors found in the present study.

Sleep allostasis in chronic sleep restriction: The role of the norepinephrine system

Sleep responses to chronic sleep restriction may be very different from those observed after acute total sleep deprivation. Specifically, when sleep restriction is repeated for several consecutive days, animals express attenuated compensatory increases in sleep time and intensity during daily sleep opportunities. The neurobiological mechanisms underlying these adaptive, or more specifically, allostatic, changes in sleep homeostasis are unknown. Several lines of evidence indicate that norepinephrine may play a key role in modulating arousal states and NREM EEG delta power, which is widely recognized as a marker for sleep intensity. Therefore, we investigated time course changes in brain adrenergic receptor mRNA levels in response to chronic sleep restriction using a rat model. Here, we observed that significantly altered mRNA levels of the α1- adrenergic receptor in the basal forebrain as well as α2- and β1-adrenergic receptor in the anterior cingulate cortex only on the first sleep restriction day. On the other hand, the frontal cortex α1-, α2-, and β1-adrenergic receptor mRNA levels were reduced throughout the period of sleep restriction. Combined with our earlier findings on EEG that sleep time and intensity significantly increased only on the first sleep restriction days, these results suggest that alterations in the brain norepinephrine system in the basal forebrain and cingulate cortex may mediate allostatic changes in sleep time and intensity observed during chronic sleep restriction.

The ‘trendiness’ of sleep: an empirical investigation into the cyclical nature of sleep time

Using Canadian time use data, we exploit variation in local unemployment rates to investigate the cyclical nature of sleep time and show that for both men and women, sleep time decreases when the economy is doing relatively better. Our results suggest that in a recession Canadians sleep an average of 3 h more per week, or 26 min more per day. Given the importance of even small changes in sleep time on measures of cognitive functioning such as reaction time and concentration, our findings may help explain the countercyclical nature of mortality. Further, as we find that sleep is affected by the same economic variables (notably the unemployment rate) that affect market work time, our results also contribute to the limited literature that shows that sleep time should not be treated as exogenously determined, but, like any other resource, determined by its relative cost.

Age effects on spectral electroencephalogram activity prior to dream recall

Ageing is associated with marked changes in sleep timing, structure and electroencephalographic (EEG) activity. Older people exhibit less slow-wave and spindle activity during non-rapid eye movement (NREM) sleep, together with attenuated levels of rapid eye movement (REM) sleep as compared to young individuals. However, the extent to which these age-related changes in sleep impact on dream processing remains largely unknown. Here we investigated NREM and REM sleep EEG activity prior to dream recall and no recall in 17 young (20-31 years) and 15 older volunteers (57-74 years) during a 40 h multiple nap protocol. Dream recall was assessed immediately after each nap. During NREM sleep prior to dream recall, older participants displayed higher frontal EEG delta activity (1-3 Hz) and higher centro-parietal sigma activity (12-15 Hz) than the young volunteers. Conversely, before no recall, older participants had less frontal-central delta activity and less sigma activity in frontal, central and parietal derivations than the young participants. REM sleep was associated to age-related changes, such that older participants had less frontal-central alpha (10-12 Hz) and beta (16-19 Hz) activity, irrespective of dream recall and no recall. Our data indicate that age-related differences in dream recall seem to be directly coupled to specific frequency and topography EEG patterns, particularly during NREM sleep. Thus, the spectral correlates of dreaming can help to understand the cortical pathways of dreaming.