Sleep deficiency among people living with human immunodeficiency virus: A growing challenge.

PURPOSE OF REVIEW: The purpose of this narrative review is to consolidate and summarize the existing literature on sleep deficiency among people living with human immunodeficiency virus (HIV; PLWH), to discuss the potential impact of antiretroviral therapy on sleep deficiency and to identify priorities for future research in this area. RECENT FINDINGS: Three important domains of sleep deficiency include alterations in sleep quality (including sleep disorders), duration and timing. The existing HIV and sleep deficiency literature, which is robust for sleep quality but sparser for sleep duration or sleep timing, has identified epidemiological correlates and outcomes associated with sleep deficiency including sociodemographic factors, HIV-specific factors, aspects of physical and mental health and cognition. SUMMARY: Sleep deficiency is a common problem among PLWH and is likely underdiagnosed, although more high-quality research is needed in this area. Sleep quality has received the most attention in the literature via methodologies that assess subjective/self-reported sleep quality, objective sleep quality or both. There is significantly less research on sleep duration and minimal research on sleep timing. Use of certain antiretroviral therapy drugs may be associated with sleep deficiency for some individuals. Future research should utilize larger, longitudinal studies with consistent, comprehensive and validated methods to assess both subjective and objective measures of sleep deficiency to better understand the prevalence, correlates and clinical implications of sleep deficiency in PLWH.

Sleep timing behaviour, sleep duration and adherence to obesogenic dietary patterns from pre-school to school age: results from the Portuguese birth cohort Generation XXI.

In an obesogenic environment, short sleeping may increase opportunistic eating. The timing of sleep might also influence the drive to eat. This study investigated the prospective association of sleep timing and duration with diet in 5286 children from the Portuguese birth cohort Generation XXI, evaluated at 4 and 7 years of age. At 4 years, sleep duration was categorised into ≤10 and >10 h. Four sleep timing categories were generated based on the median split for sleep-onset and -offset times: 'Early Sleep-Early Wake'; 'Early Sleep-Late Wake'; 'Late Sleep-Early Wake'; 'Late Sleep-Late Wake'. At 7 years, diet was obtained by a food frequency questionnaire and three dietary patterns were included: 'Healthier', 'Energy-Dense Foods (EDF)' and 'Snacking'. The Healthy Eating Index was used to evaluate diet quality. Multinomial logistic regression models and generalised linear models were performed. Children who had a late sleep, independently of the time of waking up, had higher odds of following the 'EDF' pattern, compared with the 'Healthier'. Boys who had late sleep and/or late wake had also higher odds of following the 'Snacking' pattern and had poorer diet quality. In both sexes, a late sleep or late wake were associated with a lower diet quality, compared to the group 'Early Sleep-Early Wake', and independently of nap behaviour. In boys, shorter sleep duration was associated with a poorer diet. In conclusion, pre-schoolers with late bedtimes or wake-up times have worse dietary patterns and poorer diet quality at the age of 7 years, which seems to be independent of sleep duration.

Combined effects of sleep timing and nighttime sleep duration on non-alcoholic fatty liver disease.

BACKGROUND: While short sleep duration is linked to higher risk of non-alcoholic fatty liver disease (NAFLD), the combined effects of sleep timing and sleep duration on NAFLD are less explored. METHODS: In this cross-sectional study of 39,471 participants from Beijing-Tianjin-Hebei region of China, self-reported sleep information and ultrasonography-diagnosed NAFLD were obtained from Jan 2018 to Jan 2020. Sleep timing was categorized based on sleep midpoint: early-type (before 2:00 AM), intermediate-type (2:00-2:30 AM), and late-type (after 2:30 AM). We used multivariable logistic regression to explore the relationship between sleep timing, duration, and NAFLD. We analyzed sleep midpoint and duration categorically and continuously, and conducted stratification analyses by age, sex, body mass index, hypertension, diabetes, and dyslipidemia. RESULTS: Intermediate-type (OR: 1.15, 95% confidence interval: 1.05-1.26) and late-type sleep timing (OR: 1.08, 1.00-1.16) were associated with higher NAFLD risk compared to early-type. Additionally, longer sleep duration was linked to lower risk (OR: 0.92, 0.90-0.95 per hour increase). Notably, intermediate to late-type sleepers with normal sleep duration (7 to <8 h) exhibited a 20% higher NAFLD risk compared to early-type sleepers with the same duration (OR: 1.20, 1.04-1.39). The increased NAFLD risk associated with intermediate to late sleep timing was particularly evident in men, hypertension, and prediabetes or diabetes participants. CONCLUSIONS: Intermediate to late sleep timing, even with normal sleep duration, is associated with increased NAFLD risk. These findings underscore the importance of considering both sleep timing and sleep duration for NAFLD prevention, especially in men and individuals with cardiometabolic conditions.

Sleep duration and social jetlag in healthy adolescents. Association with anxiety, depression, and chronotype: a pilot study.

PURPOSE: Misalignment between sleep opportunity and chronotype preference during adolescence may affect sleep and mental health. The aim of this study was to objectively evaluate sleep duration and social jetlag (SJL) to observe if there is a relationship with anxiety, depression, or chronotype. METHODS: Community based cohort study (n = 65) was conducted in Northern Europe. Participants recorded their sleep during the regular school schedule for 3 school nights and 2 free nights with FDA-cleared/EU Medical Device Directive (CE-02862) compliant home sleep test. They also completed validated questionnaires to assess (Morningness Eveningness Questionnaire; MEQ), sleepiness (Epworth Sleepiness Scale; ESS), and insomnia (Insomnia Severity Index; ISI), anxiety (General Anxiety Disorder-7; GAD-7), and depression symptoms (Beck's Depression Inventory-II; BDI-II). Data were collected during the last week of February and the first 2 weeks of March, 2023. RESULTS: Average sleep duration on school nights was 7 h, 15 min, with 18% of participants on average sleeping ≥ 8 h. Average sleep onset was significantly later on free nights (1 hour, 47 minutes; p < 0.0001) causing a high prevalence of moderate-severe SJL, in 71% of participants. Evening chronotypes (prevalence 15.4%) fell asleep later on free nights, causing them to have significantly more SJL (2 hours, 58 minutes) than morning chronotypes (1 hour, 32 minutes) and intermediary chronotypes (1 hour, 36 minutes). Evening chronotypes also had more severe insomnia (ISI + 4.4, p = 0.006; + 4.0, p = 0.001) and greater depressive symptoms (BDI-II + 21.6, p < 0.0001; + 17.1, p < 0.0001). A significant negative correlation was observed between MEQ scores and ESS (r = - 0.287; p = 0.001), ISI (r = - 0.343, p < 0.0001), GAD-7 (r = - 0.185, p < 0.0001), BDI-II (r = - 0.501, p = 0.0001), and suicidal thoughts (r = - 0.294, p = 0.017). CONCLUSION: Adolescents are sleep-deprived and have a high prevalence of SJL that is positively correlated with depressive symptoms and evening chronotype. That evening chronotypes have shorter sleep duration, more severe SJL, and significantly more sleepiness and insomnia, anxiety, and depressive symptoms may indicate possible benefits in identifying this group with the aim to assist them in improving their sleep habits with potentially positive effects on mental health.

Circadian misalignment proxies, BMI, and chronic conditions: the role for weekday to weekend sleep differences.

OBJECTIVE: To evaluate whether social jet lag (SJL) and weekend catch-up sleep (CUS), proxies of circadian misalignment, were associated with BMI and chronic conditions. METHODS: Participants (n = 2,050,18-65y) were part of a virtual cross-sectional and population-based research. We examined CUS and SJL as continuous and categorical (< 1 h,1-2 h, > 2 h). Linear regression analyses were performed to assess the differences in BMI (outcome) associated with CUS and SJL. Restricted cubic splines were performed to explore the shape of the relationship between weekday-to-weekend variability in sleep duration, midpoint, wake time, and bedtime. Logistic regression models were used to estimate ORs(95%CIs) for chronic conditions and overweight related to CUS and SJL. Analyses were adjusted for sleep duration, biological and behavior-related variables. RESULTS: We found a positive association of SJL and CUS with BMI. The effects remained even after adjustment for weekly sleep duration and demonstrated a proportional increase with the magnitude of sleep variability. Among participants with SJL > 2 h, BMI increased by 2.29 kg/m2 (95%CI:0.84;3.74,p:0.002). They also had 129% higher odds of chronic conditions (95%CI:1.16;4.52, p:0.01) and 119% higher odds of overweight (95%CI: 1.20;3.98,p:0.01). Individuals with CUS > 2 h presented 78% higher odds of overweight (95%CI:1.27;2.50,p:0.001) and an increase of 1.61 kg/m2 in BMI (95%CI: 0.81; 2.40,p < 0.001). CONCLUSIONS: Our findings, which demonstrate that even a slight weekend sleep extension and variability of just 1 h is associated with higher values of BMI, suggest incorporating measures for sleep consistency and regularity into clinical protocols and public health guidelines to prevent and treat obesity and related diseases.

Weekday and weekend sleep times across the human lifespan: a model-based simulation.

PURPOSE: The shifts in the opposite directions, toward later and earlier sleep timing, occur during the transition through adolescence and adulthood, respectively. Such a n-shape of age-associated change in sleep timing does not resemble the inverse relationship of sleep duration with ages. Age-associated variation in the parameters of the mechanisms of circadian and homeostatic regulation of sleep would underlie these different shapes of relationship of sleep times with ages. Here, we searched for a parsimonious explanation of these different shapes by simulating sleep times on weekdays and weekends with one of the variants of the two-process model of sleep regulation. METHODS: Using mean age of a sample with reported sleep times on weekdays and weekends, the whole set of 1404 such samples was subdivided into 15 age subsets. Simulations of sleep times in these subsets were performed with and without the suggestion of age-associated variation in the circadian phase. RESULTS: Simulations showed that the age-associated decay of slow-wave activity can parsimoniously explain not only the parallel decreases in weekend sleep duration and rate of the buildup of sleep pressure during the wake phase of the sleep-wake cycle, but also both the delay and advance of sleep timing during the transition through adolescence and adulthood, respectively. CONCLUSION: The almost functional relationships were revealed between the age-related changes in sleep duration, rate of the buildup of sleep pressure, and slow-wave activity that is a good electrophysiological marker of cortical metabolic rate and synaptic density, strength and efficacy.

Daily and average associations of physical activity, social media use, and sleep among adolescent girls during the COVID-19 pandemic.

Adolescents' daily lives have been disrupted during the Coronavirus disease 2019 (COVID-19) pandemic. It remains unclear how changes in adolescents' daily physical and social behaviours affect their sleep. The present study examined the daily and average effects of physical activity and social media use (i.e., video chatting, texting, and social networking sites) on adolescent girls' sleep during the COVID-19 pandemic. Adolescent girls aged 12-17 years (N = 93; 69% White) from a larger longitudinal study completed a 10-day daily diary protocol during state-mandated stay-at-home orders. Girls reported on daily sleep (duration, timing, quality), physical activity, and social media use during COVID-19. Multilevel modelling was used to examine the within- and between-person effects of physical activity and social media on sleep duration, timing, and quality during the 10-day period. Between-person associations indicate that youth with greater social media use (texting, video chatting, and social networking) and less physical activity had later sleep timing across the 10-day study period. Only video chatting was associated with shorter sleep duration. There were no within-person effects of physical activity or social media activities on sleep outcomes. Findings indicate that physical activity and social media use may impact later adolescent sleep timing during the COVID-19 pandemic. It will be critical for research to examine the potential long-term costs of delayed sleep timing, and whether targeting specific youth behaviours associated with sleep and circadian disruption improve mental and physical health during the COVID-19 pandemic and beyond.

Shorter sleep among adolescents is associated with lower fruit and vegetable consumption the following day.

BACKGROUND: Insufficient sleep has been associated with weight gain and metabolic dysregulation, with one suggested mechanism being through reduction in diet quality. Experimental evidence supports a causal effect of sleep timings on diet but this may not be applicable to a free-living adolescent population. In this analysis we use daily measures of sleep timings and diet quality, to examine the effect of sleep duration and timing on diet quality the following day among free-living adolescents. METHODS: The ROOTS study is a prospective cohort recruited from secondary schools in Cambridgeshire and Suffolk (UK). Participants (n = 815) at mean age 15.0y (SD 0.3y) completed a diet diary and wore a combined heart rate and accelerometer device over 4 consecutive days. Sleep duration and timing (midpoint) were derived from acceleration and heart rate traces, while daily energy density and fruit and vegetable intake were calculated from dietary data. Analyses were performed at day-level (1815 person-days). Multilevel random effects models were used to test associations between sleep each night and subsequent day diet, with daily sleep and diet measures nested within individuals and schools, and adjusted for day-level and individual-level confounding variables. RESULTS: Adolescents slept a mean of 7.88 hrs (SD 1.10) per night, reporting a mean energy density of 2.12 kcal/g (SD 0.48) and median energy-adjusted daily fruit and vegetable intake of 137.3 g (IQR 130.4). One hour shorter sleep duration was associated with lower intake of fruit and vegetables (-6.42 g, 95%CI -1.84, -10.99) the following day. An association with higher dietary energy density (0.016 kcal/g, 95%CI 0.034, -0.002) the following day was observed but did not reach statistical significance. Sleep timing was not associated with either fruit and vegetable intake (-2.52 g/d, 95%CI -7.66, 2.62) or dietary energy density (-0.001 kcal/g, 95%CI -0.022, 0.020). CONCLUSIONS: Our observational findings from a free-living adolescent population support the experimental evidence for a causal role of sleep on diet, with shorter sleep duration at night leading to a small decrease in diet quality the following day. These findings support experimental evidence to suggest inclusion of sleep duration as one component of interventions designed to improve diet quality and weight status in adolescents.

Weekend sleep after early and later school start times confirmed a model-predicted failure to catch up sleep missed on weekdays.

BACKGROUND: Many people believe they sleep for longer time on weekend nights to make up for sleep lost on weekdays. However, results of simulations of risetimes and bedtimes on weekdays and weekends with a sleep-wake regulating model revealed their inability to prolong weekend sleep. In particular, they predicted identical durations of weekend sleep after weeks with relatively earlier and relatively later risetime on weekdays. In the present study, this paradoxical prediction was empirically confirmed. METHODS: Times in bed were calculated from weekday and weekend risetimes and bedtimes in pairs of samples of students with early and later school start time and in subsets of samples from 7 age groups with weekday risetime earlier and later than 7:00 a.m. RESULTS: Among 35 pairs of students, mean age ± standard deviation was 14.5 ± 2.9 years and among the age group samples, 21.6 ± 14.6 years. As predicted by the simulations, times in bed on weekends were practically identical in the samples with early and later school start time and in two subsets with earlier and later weekday risetime. CONCLUSIONS: The model-based simulations of sleep times can inform an individual about an amount of irrecoverable loss of sleep caused by an advance shift of wakeups on weekdays.

Device-assessed sleep and physical activity in individuals recovering from a hospital admission for COVID-19: a multicentre study.

BACKGROUND: The number of individuals recovering from severe COVID-19 is increasing rapidly. However, little is known about physical behaviours that make up the 24-h cycle within these individuals. This study aimed to describe physical behaviours following hospital admission for COVID-19 at eight months post-discharge including associations with acute illness severity and ongoing symptoms. METHODS: One thousand seventy-seven patients with COVID-19 discharged from hospital between March and November 2020 were recruited. Using a 14-day wear protocol, wrist-worn accelerometers were sent to participants after a five-month follow-up assessment. Acute illness severity was assessed by the WHO clinical progression scale, and the severity of ongoing symptoms was assessed using four previously reported data-driven clinical recovery clusters. Two existing control populations of office workers and individuals with type 2 diabetes were comparators. RESULTS: Valid accelerometer data from 253 women and 462 men were included. Women engaged in a mean ± SD of 14.9 ± 14.7 min/day of moderate-to-vigorous physical activity (MVPA), with 12.1 ± 1.7 h/day spent inactive and 7.2 ± 1.1 h/day asleep. The values for men were 21.0 ± 22.3 and 12.6 ± 1.7 h /day and 6.9 ± 1.1 h/day, respectively. Over 60% of women and men did not have any days containing a 30-min bout of MVPA. Variability in sleep timing was approximately 2 h in men and women. More severe acute illness was associated with lower total activity and MVPA in recovery. The very severe recovery cluster was associated with fewer days/week containing continuous bouts of MVPA, longer total sleep time, and higher variability in sleep timing. Patients post-hospitalisation with COVID-19 had lower levels of physical activity, greater sleep variability, and lower sleep efficiency than a similarly aged cohort of office workers or those with type 2 diabetes. CONCLUSIONS: Those recovering from a hospital admission for COVID-19 have low levels of physical activity and disrupted patterns of sleep several months after discharge. Our comparative cohorts indicate that the long-term impact of COVID-19 on physical behaviours is significant.

Worse sleep health predicts less frequent breakfast consumption among adolescents in a micro-longitudinal analysis.

BACKGROUND: Poor self-reported sleep health has been linked to not consuming breakfast in adolescents, but it is unknown whether poor sleep measured objectively predicts next-day breakfast consumption within adolescents. We investigated within- and between-person associations of objectively measured sleep dimensions and subjective sleep quality with adolescent breakfast consumption. METHODS: Data were collected from a micro-longitudinal substudy of the Year 15 wave of the Fragile Families and Child Wellbeing Study (n = 590). Adolescents wore an actigraphy device and completed daily diaries for ~ 1 week (M ± SD = 5.6 ± 1.4 nights per adolescent, range: 3-9), where they rated their sleep quality and reported whether they had eaten breakfast that day, with no specific definition of breakfast provided (M ± SD = 5.5 ± 1.4 days per adolescent, range: 3-9). Separate mixed models assessed whether actigraphy-measured sleep duration (linear and quadratic, sleep duration x sleep duration), timing, maintenance efficiency, and subjective quality predicted odds of breakfast consumption both within and between adolescents. Variability of sleep duration and timing (standard deviation per person), sleep regularity index (SRI), and social jetlag were tested as additional between-person predictors. Analyses with predictors other than sleep duration were adjusted for sleep duration. RESULTS: Following nights when adolescents had shorter or longer sleep duration (p = .005; curvilinear association), later sleep onset, or later sleep midpoint (both p = .025) than their own usual, they had lower odds of consuming breakfast the next day (within-person associations). Adolescents who on average had later sleep onset (p = .013) or midpoint (p = .013) or who reported lower sleep quality (p = .011) had lower average odds of consuming breakfast (between-person associations). Adolescents with greater variability of sleep duration (p = .005), midpoint (p = .004), or offset (p < .001) had lower average odds of consuming breakfast (between-person associations). Sleep maintenance efficiency (within or between adolescents), SRI, and social jetlag were not associated with breakfast consumption (all p > .10). CONCLUSIONS: Multiple dimensions of sleep health are associated with breakfast consumption, both within and between adolescents. Poor sleep and dietary behaviors in adolescence may negatively impact future metabolic health.

Sleep during "lockdown" highlighted the need to rethink the concept of weekend catch-up sleep.

PURPOSE: Many people believe in their ability to sleep for longer time on weekends to make up for sleep lost due to early wakeups on weekdays. This widely held belief was not supported by the simulations of rise- and bedtimes on weekdays and weekends with a sleep-wake regulating model. The simulations suggested the inability to extend sleep on any of two weekend nights and they predicted identical weekend sleep durations for weeks with relatively earlier and relatively later weekday risetimes. By April 2020, about half of the world's population was under some form of "lockdown" due to the COVID-19 pandemic. This "lockdown" provided a new opportunity to demonstrate the predictive power of the sleep-wake regulating models. Therefore, the purpose of this report was to support the prediction of identity of weekend sleep durations after weeks with earlier and later weekday wakeups. METHODS: Weekend and weekday rise- and bedtimes before and during "lockdown" for 31 samples were taken from recent journal publications. Time in bed on weekends and 12 other measures of sleep duration and timing were calculated and simulated. RESULTS: For only one of 13 measures, weekend time in bed, statistical analysis did not yield a statistically significant difference between the estimates obtained before and during "lockdown". The model-based simulations pointed to the 0.3-h delay of the sleep-wake cycle in response to the 1-h delay of weekday risetime during "lockdown". CONCLUSION: The model-based prediction was confirmed, thus, highlighting again the necessity to rethink the concept of weekend catch-up sleep.

Association between sleep duration and albumin in US adults: a cross-sectional study of NHANES 2015-2018.

BACKGROUND: Albumin has multiple functions and is used in the clinical assessment of liver function, kidney function and nutritional status. However, few epidemiological studies have evaluated the association between sleep duration and albumin. Therefore, we carried out a cross-sectional study to address this issue. The aim of the study was to investigate the association between sleep duration and albumin in American adults based on the NHANES (National Health and Nutrition Examination Survey). METHODS: A total of 9,973 participants aged [Formula: see text] 20 years were included in this study from NHANES 2015-2018. Weighted data were calculated according to analytical guidelines. Linear regression models and smooth curve fitting were used to assess and describe the relationship between sleep duration and albumin. The inflection point was determined by a two-step recursive method. Moreover, univariate and stratified analyses were performed. RESULTS: There was an inverted U-shaped association between sleep duration and albumin levels. Albumin levels were highest when the sleep duration was 7.5 h. Compared to 7-8 h of sleep, short sleep duration was linked to lower albumin levels [sleep duration [Formula: see text] 5 h: ß [Formula: see text]-1.00, 95% CI (-1.26, -0.74), P < 0.0001]. Compared to 7-8 h of sleep, long sleep duration was related to lower albumin levels [sleep duration [Formula: see text] 9 h: ß [Formula: see text] -0.48, 95% CI (-0.68, -0.27), P < 0.0001]. CONCLUSIONS: Sleep duration had an inverted U-shaped relationship with albumin, with short or long sleep duration associated with significantly lower albumin levels.

Assessing Changes in Adolescents' Sleep Characteristics and Dietary Quality in the START Study, a Natural Experiment on Delayed School Start Time Policies.

BACKGROUND: Sleep duration, quality, and timing may influence dietary quality. In adults, poor dietary quality is a risk factor for numerous chronic diseases. It is unclear how these various sleep domains influence adolescents' diets because prior population-based studies have not effectively manipulated sleep, did not include objective sleep measures, and had short follow-up times. OBJECTIVES: The objectives of this study were to examine 1) how adolescent sleep characteristics relate to dietary quality; and 2) how delay in high school start times (which lengthened sleep duration) affects dietary quality over 2 y. METHODS: In the START study, adolescents (grades 9-11, n = 423) attending 5 high schools in the Minneapolis, Minnesota metropolitan area were annually assessed in 3 waves (2016-2018). At Baseline, all schools started "early" (07:30 or 07:45). From Follow-up 1 through Follow-up 2, 2 "policy change schools" shifted to later start times (to 08:20 and 08:50). Three "comparison schools" maintained their early start throughout. Sleep characteristics were measured with actigraphy. Mixed-effect regression models were used to examine cross-sectional and longitudinal associations of sleep characteristics with dietary quality, and school start time policy change with dietary quality change. RESULTS: Cross-sectionally, later sleep midpoint and onset were associated with dietary quality scores 1.6-1.7 lower (both P < 0.05). However, no prospective associations were observed between sleep characteristics and dietary quality in longitudinal models. Shifting to later school start time tended to be associated with a 2.4-point increase in dietary quality score (P = 0.09) at Follow-up 1, but was not associated with change in dietary quality scores at Follow-up 2 (P = 0.35). CONCLUSIONS: High school students attending delayed-start schools maintained better dietary quality than students in comparison schools; however, differences were not statistically significant. Overall study findings highlight the complexity of the relation between sleep behavior and diet in adolescence.

Sleep, Circadian Rhythmicity and Response to Chronotherapy in University Students: Tips from Chronobiology Practicals.

Chronobiology is not routinely taught to biology or medical students in most European countries. Here we present the results of the chronobiology practicals of a group of students of the University of Padova, with a view to highlight some interesting features of this group, and to share a potentially interesting cross-faculty teaching experience. Thirty-eight students (17 males; 22.9 ± 1.6 yrs) completed a set of self-administered electronic sleep quality [Pittsburgh Sleep Quality Index (PSQI)], chronotype and sleepiness [Epworth Sleepiness Scale (ESS)] questionnaires. They then went on to complete sleep diaries for two weeks. Sixteen also wore an actigraph, 8 wore wireless sensors for skin temperature, and 8 underwent a course of chronotherapy aimed at anticipating their sleep-wake timing. Analyses were performed as practicals, together with the students. Average PSQI score was 5.4 ± 1.9, with 15 (39%) students being poor sleepers. Average ESS score was 6.5 ± 3.3, with 3 (8%) students exhibiting excessive daytime sleepiness. Seven classified themselves as definitely/moderately morning, 25 as intermediates, 6 as moderately/definitely evening. Students went to bed/fell asleep significantly later on weekends, it took them less to fall asleep and they woke up/got up significantly later. Diary-reported sleep onset time coincided with the expected decrease in proximal skin temperature. Finally, during chronotherapy they took significantly less time to fall asleep. In conclusion, significant abnormalities in the sleep-wake patterns of a small group of university students were observed, and the students seemed to benefit from chronotherapy. We had a positive impression of our teaching experience, and the chronobiology courses obtained excellent student feedback.

Sleep timing and hygiene practices of high bedtime procrastinators: a direct observational study.

BACKGROUND: Bedtime procrastination (BP) has been proven to be an important indicator of sleep insufficiency from a psychological perspective. However, the effect of BP on sleep patterns related to sleep deficiency remains unknown. OBJECTIVE: This study aimed to investigate the characteristics of self-reported sleep timing and hygiene practices between high and low-moderate bedtime procrastinators. It also aimed to examine the relationship between these characteristics and high level of BP. METHODS: A total of 391 Chinese college students were recruited for this study. Participants completed questionnaires on demographics, sleep timing variables, the Sleep Hygiene Practice Scale (SHPS) and the Bedtime Procrastination Scale (BPS). RESULTS: High bedtime procrastinators were more likely to have higher SHPS global and subdomain scores (Ps < 0.001). They also were more likely to exhibit later sleep onset, sleep offset and rise time on both weekdays and weekends (Ps < 0.01). The significant independent determinant factors of the prevalence of high BP were: SHPS total score [odds ratio (OR) = 1.05, P < 0.001], arousal-related behaviour (OR = 1.07, P = 0.007), sleep schedule and timing (OR = 1.12, P < 0.001) and sleep onset on weekdays (OR = 2.65, P < 0.001). CONCLUSIONS: High bedtime procrastinators showed maladaptive sleep-related variables, which mainly manifested as changes in arousal-related behaviour and sleep schedule and timing, as well as delays in sleep onset time on weekdays. The findings could help guide the formulation of appropriate interventions in primary health care.

Circadian Rhythms in Obsessive-Compulsive Disorder: Recent Findings and Recommendations for Future Research.

PURPOSE OF REVIEW: Circadian rhythms are a topic of growing interest in mental health, particularly in obsessive-compulsive disorder. However, the consistency of this link has not been carefully examined. Thus, the present review integrates findings from the past 5 years in order to determine the strength of such a relationship and identify areas for clarification and extension. RECENT FINDINGS: Findings revealed inconsistent evidence for a link between circadian rhythms and OCD. Chronotype is unrelated to OCD symptoms in adolescents but predicts OCD symptoms in adults. Results on delayed sleep timing are equivocal. Circadian rhythm disorders predict OCD treatment outcome. Preliminary evidence implicates decreased light exposure and diurnal symptom variability in OCD. The relationship between circadian rhythms and OCD may vary by age, diagnostic status, and assessment method. Recent findings are limited by an overreliance on convenience samples and singular self-report methods. Recommendations for future research on the role of circadian rhythms in OCD are discussed.

Are sleep hygiene practices related to the incidence, persistence and remission of insomnia? Findings from a prospective community study.

The purpose was to examine whether sleep hygiene practices are associated with the course of insomnia (incidence, persistence and remission) over 1 year in the general population. This longitudinal study was carried out in the general population. After excluding anyone with other primary sleep disorder than insomnia, 1638 participants returned a baseline and a 1-year follow-up survey. Questions regarding sleep hygiene practices were administered at baseline, and the status of insomnia was assessed at baseline (T1) and at the 1-year follow-up (T2). Age, gender, mental ill-health, and pain were used as covariates in the analyses. Nicotine use, mental ill-health and pain were independently associated with an increased risk for concurrent insomnia at T1, while mental ill-health was the only risk factor for incident insomnia at T2. Relative to not reporting insomnia at the two time-points, nicotine use, light or noise disturbance, mental ill-health, and pain significantly increased the risk for persistent insomnia over 1 year. In comparison with those whose insomnia had remitted at the follow-up, reporting an irregular sleep schedule was a significant risk factor for persistent insomnia. Of the nine sleep hygiene practices examined in this study, only three were independently linked to concurrent and future insomnia, respectively; using nicotine late in the evening, light or noise disturbance, and having an irregular sleep schedule. This may have implications for the conceptualization and management of insomnia as well as for future research.

Toxoplasma gondii IgG associations with sleep-wake problems, sleep duration and timing.

BACKGROUND: Evidence links Toxoplasmagondii (T. gondii), a neurotropic parasite, with schizophrenia, mood disorders and suicidal behavior, all of which are associated and exacerbated by disrupted sleep. Moreover, low-grade immune activation and dopaminergic overstimulation, which are consequences of T. gondii infection, could alter sleep patterns and duration. METHODS: Sleep data on 833 Amish participants [mean age (SD) = 44.28 (16.99) years; 59.06% women] were obtained via self-reported questionnaires that assessed sleep problems, duration and timing. T. gondii IgG was measured with ELISA. Data were analyzed using multivariable logistic regressions and linear mixed models, with adjustment for age, sex and family structure. RESULTS: T. gondii seropositives reported less sleep problems (p < 0.005) and less daytime problems due to poor sleep (p < 0.005). Higher T. gondii titers were associated with longer sleep duration (p < 0.05), earlier bedtime (p< 0.005) earlier mid-sleep time (p < 0.05). CONCLUSIONS: It seems unlikely that sleep mediates the previously reported associations between T. gondii and mental illness. Future longitudinal studies with objective measures are necessary to replicate our findings.

Naturally occurring circadian rhythm and sleep duration are related to executive functions in early adulthood.

Experimental sleep deprivation studies suggest that insufficient sleep and circadian misalignment associates with poorer executive function. It is not known whether this association translates to naturally occurring sleep patterns. A total of 512 of full-term-born members of the Arvo Ylppö Longitudinal Study [mean age = 25.3, standard deviation (SD) = 0.65] (44.3% men) wore actigraphs to define sleep duration, its irregularity and circadian rhythm (sleep mid-point) during a 1-week period (mean 6.9 nights, SD = 1.7). Performance-based executive function was assessed with the Trail-Making Test, Conners' Continuous Performance Test and Stroop. The self-rated adult version of Behavior Rating Inventory of Executive Function was used to assess trait-like executive function. We found that performance-based and self-reported trait-like executive function correlated only modestly (all correlations ≤0.17). Shorter sleep duration associated with more commission errors. Later circadian rhythm associated with poorer trait-like executive function, as indicated by the Brief Metacognitive Index and the Behavior Regulation Index. Those belonging to the group with the most irregular sleep duration performed slower than others in the Trail-Making Test Part A. All associations were adjusted for sex, age, socioeconomic status and body mass index. In conclusion, naturally occurring insufficient sleep and later circadian rhythm showed modest associations with poorer executive function. Shorter habitual sleep duration was associated with lower scores of performance-based tests of executive function, and later circadian rhythm was associated mainly with poorer trait-like executive function characteristics. Our findings suggest additionally that sleep duration and circadian rhythm associate with different domains of executive function, and there are no additive effects between the two.