Greater Morningness Research Articles

Sleep-wake timing and chronotype in perinatal periods: longitudinal changes and associations with insomnia symptoms, sleep-related impairment, and mood from pregnancy to 2 years postpartum.

Across the perinatal transition, existing research focuses mainly on significant changes in sleep duration and quality, neglecting sleep timing. This study investigated change trajectories of sleep timing and chronotype from late pregnancy to 2 years postpartum and examined longitudinal associations of chronotype with symptoms of insomnia, daytime sleep-related impairment, and mood. Data were from a two-arm randomised controlled trial testing parent-focused wellbeing interventions. Participants were a community sample of nullipara without severe sleep/mental health conditions. Participants self-reported bedtime, rise-time, chronotype, insomnia symptoms, sleep-related impairment, depression, and anxiety at seven time points: gestation Weeks 30 and 35, and postpartum Months 1.5, 3, 6, 12 and 24. Trajectories were estimated using mixed-effects models with continuous time, quadratic splines, and a knot at childbirth, controlling for age and group allocation. A total of 163 participants (mean [SD] age 33.35 [3.42] years) took part. Bedtime and rise-times delayed during late pregnancy (~8 and ~20 min, respectively) but became progressively earlier (~20 and ~60 min, respectively) over the 2 postpartum years. Chronotype became more eveningness in late pregnancy, and more morningness after childbirth, however changes were small. Controlling for sleep duration and efficiency, greater morningness was associated with significantly less symptoms of insomnia and sleep-related impairment over time (all p < 0.001); longitudinal associations between chronotype and symptoms of depression and anxiety were non-significant (all p > 0.65). Sleep-wake timing and chronotype became progressively earlier from pregnancy to 2 years postpartum. Morningness chronotype may be sleep-protective during the transition from pregnancy to parenthood. Mechanisms underlying these associations require further research.

0769 Multidimensional Sleep Health in Adolescents from the General Population: Definition, Thresholds and Construct Validity

Abstract Introduction The RU-SATED model – regularity, satisfaction, alertness, timing, efficiency, and duration – captures the 24-hour experience of sleep to asses multidimensional sleep health (MSH). However, most prior evidence comes from middle-aged adults. We provide updated MSH data in adolescents by leveraging objective and self-reported sleep measures. Methods We studied 377 adolescents (16.4±2.3 yr; 46.4% female; 21.5% racial/ethnic minority) from the Penn State Child Cohort, a randomly-selected population-based sample. Each MSH domain was categorized as “good” or “poor” using cut-offs informed by prior studies and expert consensus. Good cut-offs, assigned a score of 1, that were derived from actigraphy-measured data included: the standard deviation of sleep midpoint ≤1-h (RU), mean of sleep midpoint 2:00-4:00 (T), mean value of sleep efficiency ≥85% (E), and mean total sleep time ≥7.5-h (D). Good cut-offs derived from self-reported rating scales included the absence of insomnia symptoms (S) or excessive daytime sleepiness (A). Values considered poor based on these cut-offs were assigned a score of 0. Scores were summed across all domains to obtain a composite score ranging from 0 to 6, with higher scores indicating better MSH. Morningness and Tanner staging were self-reported, while Sleep and Arousal clusters scores on the Pediatric Behavior Scale were parent-reported. Results The mean composite score was 3.03 ± 1.30 and domains A and D were most commonly rated as poor (64.5% and 65.3%, respectively). Younger age (r=-0.13, p&amp;lt; 0.05) and identifying as non-Hispanic white (r=-0.14, p&amp;lt; 0.01) were significantly associated with higher MSH scores, while sex (r=-0.04, p=0.40), Tanner staging (r=-0.06, p=0.29) or BMI percentile (r=-0.07, p=0.15) were not. Greater morningness (r=-0.29, p&amp;lt; 0.01), less disturbed sleep (r=-0.28, p&amp;lt; 0.01) and higher arousal (r=-0.21, p&amp;lt; 0.01) scores were associated with higher MSH scores. Conclusion Our data-driven approach can be used to assess MSH in the adolescent population. Our definition captures previously identified health disparities in MSH in adults and shows optimal construct validity against self-reports of circadian preference and parent observations of adolescents’ degree of sleep disturbance and arousal. Improving sleep duration and daytime alertness appear to continue to be the most relevant domains impacting overall MSH in adolescents. Support (if any) NIH (R01HL136587,UL1TR000127)

A longitudinal investigation of sleep hygiene as a mediator linking parental warmth with adolescent sleep.

Parental warmth in adolescence protects sleep in early adulthood, yet the nature, directions, and mechanisms of this association across adolescence are unknown. This study examined parental warmth, adolescent sleep hygiene and sleep outcomes (morning/eveningness, school night sleep duration, and daytime sleepiness) across five annual waves, spanning four years, using a cross-lagged panel design. Adolescents and one primary caregiver (96% mothers) completed questionnaires assessing parental warmth (child- and parent-report) and adolescent sleep hygiene and sleep (child-report), across five annual waves: Wave 1 (N = 531, Mage = 11.18, SD = 0.56, 51% male), Wave 2 (N = 504, Mage = 12.19, SD = 0.53, 52% male), Wave 3 (N = 478, Mage = 13.19, SD = 0.53, 52% male), Wave 4 (N = 440, Mage = 14.76, SD = 0.47, 51% male), and Wave 5 (N = 422, Mage = 15.75, SD = 0.49, 51% male). Greater child-reported parental warmth was indirectly associated with better adolescent sleep (greater morningness, longer school night sleep duration, less sleepiness) through healthier sleep hygiene. The inverse was also often observed. Warmth had a direct relationship with sleep duration and sleepiness, independent of sleep hygiene. Parent-reported parental warmth did not predict, nor was predicted by child-reported adolescent sleep. Parental warmth may protect against developmental changes in adolescent sleep, partially by improving sleep hygiene practices. Similarly, inadequate adolescent sleep may negatively impact parental warmth via deteriorating sleep hygiene. Sleep hygiene emerged as a key mechanism for protecting adolescent sleep and parent-child relationships.

Maternal Circadian Rhythm and Its Association With Meal Timing and Density: A Prospective Cohort Study

ObjectivesThis prospective cohort study aimed to examine the association between chronotype with nutritional and psychosocial factors in pregnant women. MethodsChronotype of the subjects was determined using Morningness-Eveningness Questionnaire (MEQ), whereby higher scores indicate greater morningness. Sleep quality and psychological distress were assessed using the Pittsburgh Sleep Quality Index questionnaire (PSQI) and Depression, Anxiety and Stress Scale (DASS-21) respectively. Pedometer was used to measure 5-day physical activity. Pre-pregnancy weight and height were self-reported. ResultsTo date, 100 pregnant women were approached at selected government maternal and child clinics in Kuala Lumpur, Malaysia. Subjects were mostly Malay (67%). Mean age was 28 (4.3) years; 12% were underweight and 19% were overweight/obese before pregnancy. Stress, anxiety, and depression of moderate severity or above were found in 13%, 49%, and 12% of the subjects, respectively. The prevalence of poor sleepers was 70%. Sedentary behaviour was observed in 73% of the subjects (4086 ± 2247 steps/day). In the linear regression model, chronotype was a significant predictor of stress (2 = –0.421, p = 0.015) and depression (β = –0.208, p = 0.042) during pregnancy. ConclusionsPreliminary findings from this study suggested that chronobiological approaches may be important to tackle psychological distress during pregnancy, which may impact birth outcomes and subsequently, infant growth. The circadian rhythm of subjects will be determined based on salivary hormone in the upcoming analysis. Funding SourcesMinistry of Higher Education, Malaysia. The funds were provided through the Fundamental Research Grant Scheme (FRGS/1/2018/SKK06/UCSI/02/2).

P153 Sleep timing and chronotype in perinatal periods: Longitudinal changes and associations with wellbeing from pregnancy to 2 years postpartum

Abstract Introduction Significant changes to sleep occur during perinatal periods. Existing research focuses on sleep duration and quality, but not sleep timing or chronotype. This study investigated change trajectories of sleep timing and chronotype from late pregnancy to two years postpartum, and examined associations between chronotype and insomnia, sleep-related impairment, and mood at seven different perinatal time-points. Methods Data were from a 2-arm randomised controlled trial testing behavioural sleep and diet interventions. A community sample of nulliparous females without severe sleep/mental health conditions participated. Participants self-reported bedtime, rise-time, chronotype (short Morningness-Eveningness Questionnaire), Insomnia Severity Index, and PROMIS Depression, Anxiety, and Sleep-Related Impairment over seven time points: gestation weeks 30 and 35, and postpartum months 1.5, 3, 6, 12 and 24. Results 163 participants (mean age 33.4±3.4 years) took part. Mixed effects models adjusting for age and group allocation showed that both bed- and rise-times became progressively earlier by approximately 20–30 minutes over time (p&amp;lt;.001); chronotype shifted progressively towards more morningness (p&amp;lt;.01). After adjusting for covariates (sleep duration and efficiency, mental health history, social support, age, group allocation), greater morningness was significantly associated with lower symptoms of insomnia and sleep-related impairment over time (p-values&amp;lt;.001); at each time-point, associations between chronotype and symptoms of depression and anxiety were non-significant (p-values&amp;gt;0.65). Conclusions Sleep timing and chronotype became progressively earlier over the first two postpartum years. Greater morningness was associated with less sleep complaints and sleep-related daytime impairment during the postpartum period. The mechanisms of these findings may be investigated through further research.

225 Sleep Timing and Chronotype in Mothers: Longitudinal Changes and Associations with Wellbeing from Pregnancy to 2 Years Postpartum

Abstract Introduction Women experience significant changes to sleep during perinatal periods. Existing research focuses on sleep duration and quality, but not sleep timing or chronotype (i.e., preferred timing for activity and sleep). This study investigated change trajectories of sleep timing and chronotype from late pregnancy to two years postpartum, and examined longitudinal associations between chronotype and insomnia, sleep-related daytime impairment, and mood. Methods Data were from a 2-arm randomized controlled trial testing behavioral sleep and diet interventions. A community sample of nulliparous women without severe sleep/mental health conditions participated. Women self-reported bedtime, risetime, chronotype (reduced Morningness-Eveningness Questionnaire), Insomnia Severity Index, and PROMIS Depression, Anxiety, and Sleep-Related Impairment over 7 time points: 30 and 35 weeks’ gestation, and postpartum months 1.5, 3, 6, 12 and 24. Results 163 women (mean age 33.35 ± 3.42 years) took part. Mixed effects models controlling for age and group allocation showed that both bed- and risetimes became progressively earlier over time by approximately 20-30 minutes on average (p &amp;lt; .001); chronotype also shifted progressively towards morningness (p &amp;lt; .01). After controlling for covariates (sleep duration and efficiency, mental health history, social support, age, group allocation), greater morningness was significantly associated with lower symptoms of insomnia and sleep-related impairment over time (p-values &amp;lt; .001); longitudinal associations between chronotype and symptoms of depression and anxiety were non-significant (p-values &amp;gt; .65). Conclusion This is one of the first studies to examine longitudinal changes in sleep timing and chronotype from pregnancy to two years postpartum. Sleep timing and chronotype became progressively earlier over the first two postpartum years. The magnitude of changes is beyond what is expected with increasing age. Greater morningness was associated with lower sleep complaints and sleep-related daytime impairment during the postpartum period. The mechanisms underlying these associations require further research. Support (if any) Australasian Sleep Association, Monash University, Australian Government RTP Scholarship and National Health and Medical Research Council.

Ukrainian versions of the Composite Scale of Morningness and Munich Chronotype Questionnaire

ABSTRACT Chronotype is an individual characteristic that can be important for health and quality of life. There are currently no instruments to measure chronotype in Ukrainians, so this study was conducted to provide adaptations of questionnaires with proven psychometric properties. The Composite Scale of Morningness (CSM) and the Munich ChronoType Questionnaire (MCTQ) were translated into Ukrainian using the parallel blind method; 776 Ukrainians then completed the questionnaires and answered questions on demographics and substance use. The Ukrainian version of the CSM showed high internal consistency (Cronbach’s alpha = 0.874). Greater morningness (CSM) correlated with earlier midsleep on sleep-corrected free days (MSFsc), r = −0.623. Later chronotypes as derived from both CSM and MCTQ exhibited more pronounced social jetlag and greater consumption of stimulants. In accordance with the assumptions underlying the CSM, confirmatory factor analysis proved the one-factor structure of the Ukrainian version of the questionnaire. The cut-off scores (bottom/top 10%) for the Ukrainian CSM were 23 or less for evening types and 42 or more for morning types. The Ukrainian CSM and MCTQ appear to be psychometrically sound measures of chronotype ready for use in future studies.

0777 Variations in Vigilance and Sleep Among Underground Mine Workers During 14 Consecutive Night Shifts

Abstract Introduction Adverse effects of night shift work are well known but there is scarce data on how vigilance and sleep vary across a large number of consecutive night shifts. Methods In summer, 38 underground miners (mean age (SD): 36.8 (13.9) years) wore an actigraph, filled out the Morningness-Eveningness questionnaire, and completed a Visual Analog Scale capturing subjective vigilance (very sleepy to very alert) 4 times per shift (19:00, 22:00, 02:00, and 05:30) for 14 consecutive night shifts. Mixed effects linear regression models were used to account for repeated measures. Results Mean vigilance level is lower at 22:00, 02:00 and 05:30 than at the beginning of the shift at 19:00 (p&amp;lt;0.001). Also, a more pronounced decrease in vigilance during the night was observed among older workers compared to younger workers (p&amp;lt;0.05). Moreover, workers with greater eveningness have higher vigilance at the beginning of the first night shift at 19:00 (p&amp;lt;0.001), but their decline in vigilance level during the night is faster than that observed in workers with greater morningness (p&amp;lt;0.01). Interestingly, the mean vigilance decline observed at 02:00 and 05:30 (compared to 19:00) is slowed down for each additional night shift (p&amp;lt;0.001). Furthermore, mean sleep efficiency is negatively associated with morningness and gradually decreases across consecutive night shifts (p&amp;lt;0.05). In addition, mean sleep duration is shorter in older workers and is positively associated with morningness (p&amp;lt;0.05). Conclusion Results show a progressive improvement in vigilance of mine workers assigned to a large number of consecutive 12-hour night shifts from 2 am onwards. This may probably be ascribed to an adjustment in homeostatic sleep propensity consecutive to the partial sleep deprivation associated with time spent traveling to the remote site before the first shift. However, circadian adjustment is unlikely considering the strong morning light exposure experienced daily after the night shift. Support College and Community Innovation Program of the Natural Sciences and Engineering Research Council of Canada (NSERC) (CUI2I 472201-14)

Abstract MP20: Evening Chronotype is Associated With Poor Cardiovascular Health and Adverse Health Behaviors in a Diverse Population of Women

Background: Chronotype is the behavioral manifestation of an individual’s innate circadian rhythm. Evening chronotype (i.e. being a “night owl”) is linked to elevated chronic disease and mortality risk in European and Asian populations. Evidence from US cohorts is limited, particularly among women, in whom evening chronotype prevalence becomes higher from midlife onward, coinciding with life stages and hormonal changes associated with higher cardiovascular disease (CVD) risk. Hypothesis: Being a definite evening chronotype would be associated with poor cardiovascular health (CVH) and elevated cardiometabolic risk factors. Methods: Participants were 506 diverse women (mean age=37±16y, 62% racial/ethnic minority) in the AHA Go Red for Women Strategically Focused Research Network at Columbia University. Chronotype was measured using the Morningness-Eveningness Questionnaire (MEQ), the most widely used validated tool by circadian biologists to ascertain chronotype. Higher scores reflected greater morningness. Participants were also categorized as “evening” vs. “intermediate/morning” chronotypes based on their MEQ scores. Health behaviors (diet, physical activity, sleep, and sedentary time) were assessed using validated questionnaires. Health factors (BMI, blood pressure, fasting glucose, and cholesterol) were assessed at the clinic visit. Overall CVH was evaluated using the AHA Life’s Simple 7 (LS7) score (0-8: poor, 9-14: moderate to high). Linear and logistic regression models adjusted for age, race/ethnicity, education, health insurance, and menopause were used to examine associations of chronotype with CVH, clinical risk factors, and health behaviors. Results: Overall, 13% of women identified as being evening chronotypes. Higher MEQ scores (i.e. greater morningness) were associated with higher AHA LS7 scores (β=0.02, p=0.01), indicative of more favorable CVH. Higher MEQ scores were also associated with having a lower Pittsburgh Sleep Quality Index, i.e. better sleep quality, (β=-0.07, p&lt;0.0001), a lower Insomnia Severity Index (β=-0.14, p&lt;0.0001), shorter time to fall asleep (β=-0.28, p=0.04), and less sedentary time (β=-0.11, p=0.001). In contrast, being an evening chronotype was associated with higher odds of poor CVH (OR (95%CI): 2.41 (1.20-4.85)), not meeting AHA diet (OR (95%CI): 2.89 (1.59-5.23)) and physical activity guidelines, (OR (95%CI): 1.78 (1.03-3.07)), and having short sleep (&lt;7h) (OR (95%CI): 2.15 (1.24-3.73)) or insomnia symptoms (OR (95%CI): 2.69 (1.53-4.75)). Conclusions: Women with evening chronotypes have greater odds of having poor CVH and adverse health behaviors after adjustment for sociodemographic factors and menopausal status. Chronotype may be important to consider and target in lifestyle interventions aimed at CVD prevention, particularly among middle-aged and older women who are prone to sleep changes.

Cognitive Vulnerabilities as Prognostic Predictors of Acute and Follow-up Outcomes in Seasonal Affective Disorder Treatment with Light Therapy or Cognitive-Behavioral Therapy.

First-line treatments for winter seasonal affective disorder include light therapy and cognitive-behavioral therapy; however, it is unclear whether particular patient profiles respond differentially to each treatment type. This study examined baseline patient cognitive and chronobiological vulnerabilities as prognostic and prescriptive predictors of acute and follow-up treatment outcomes. 177 adults with seasonal affective disorder were randomized to 6-weeks of either light therapy or cognitive-behavioral therapy. Participants completed baseline measures of cognitive vulnerabilities (Dysfunctional Attitudes Scale; Ruminative Response Scale; Seasonal Belief Questionnaire) and chronobiological vulnerability (Morningness-Eveningness Questionnaire). Depression was assessed at pre- and post-treatment and at follow-ups one and two winters later. Pre-treatment depression severity correlated significantly with each cognitive vulnerability measure, and significantly predicted future depression. After controlling for pre-treatment depression, higher scores on the Morningness-Eveningness Questionnaire were prognostic of lower depression at treatment endpoint, but no cognitive vulnerability emerged as a prognostic or prescriptive predictor of outcome. Greater morningness was associated with less severe post-treatment depression in both cognitive-behavior therapy and light therapy. No cognitive vulnerability emerged as a prognostic or prescriptive predictor, perhaps because they correlated with pre-treatment depression severity, a robust predictor of outcome. Future research should test alternative cognitive constructs.

Morning and evening type: The cortisol awakening response in a sleep laboratory

BackgroundEarlier evidence indicated an association between chronotype and the cortisol awakening response (CAR). However, these earlier data were collected without objective control for participant compliance being available, which, following recent guidelines, is considered critical for ensuring data validity. Here, we are seeking to replicate these earlier findings within a well-controlled sleep laboratory set up. MethodsThe sample consisted of 103 young males, including 12 participants defined as ‘evening’ (MEQ < 41) and 20 participants defined as ‘morning type’ (MEQ > 59) types. All participants slept for one night in a sleep laboratory and were wakened at 6:30 AM the next morning. Saliva samples for the assessment of the CAR were collected under strict supervision at 0, 15, and 30 min post-awakening. ResultsSignificant effects of chronotype emerged consistently from both dimensional analyses across the entire sample and from comparisons between morning vs. evening type. Overall, greater morningness was associated with an increased cortisol level upon awakening (S1) as well as with a greater overall cortisol output (AUCG), however, it was not associated with the CAR (AUCI). DiscussionOur data corroborate earlier evidence by showing that, under well-controlled sleep-laboratory conditions, chronotype is related to an altered cortisol secretion over the post-awakening period with no association with the CAR. However, the results have to be replicated since it is only a single day study design.

Psychometric properties of a Japanese version of Composite Scale of Morningness

This study aimed to assess the factor structure and validity of the Composite Scale of Morningness (CSM) in Japanese samples. A sample of 348 Japanese university students (196 men, 152 women) and 170 adults from the community (50 men, 120 women) completed a questionnaire including the CSM, the Diurnal Type Scale (DTS) and questions regarding sleeping and waking times. Four measurement models were compared, and a two-factor measurement model with Morningness/Time of day preference (α = 0.78) and Morning Affect/Alertness (α = 0.80) factors yielded the closest fit. Both Morningness/Time of day preference and Morning Affect/Alertness were positively correlated with DTS score. Morningness/Ttime of day preference was negatively correlated with the midpoint of sleep on weekdays and free days. The measurement model was invariant across the university and community groups. The community group, which was older, was characterized by greater morningness. The results provide evidence of the validity of the Japanese CSM, thus opening up the possibility of including Japanese samples in cross-cultural research on morningness.

M32 - PER3 POLYMORPHISMS, MORNINGNESS-EVENINGNESS AND DEPRESSION: PRELIMINARY EVIDENCE IN A BRAZILIAN FAMILY-BASED COHORT, THE BAEPENDI HEART STUDY

Background There is a significant interest in the contribution of the circadian timing system to individual differences in a wider range of behaviour. This is in part because sleep complaints and disturbances of the circadian timing system are common in psychiatric disorders. Based on diurnal preference, people can be divided into chronotypes with demonstrated differences in sleep-wake patterns and a variety of circadian rhythms, behavioral rhythms, and diurnal variation in mood. Specifically, greater eveningness has been related to greater depression. The human PER3 gene contains a variable number tandem repeat (VNTR) which is associated with diurnal preference: the longer allele (five tandem repeats) has been reported to associate with greater morningness, and the shorter allele (four tandem repeats) with greater eveningness. We have investigated the PER3 polymorphism and its relationship to sleep, circadian and depression characteristics in a Brazilian family-based cohort. Methods Baependi is a small rural town in Brazil that provides a window of opportunity to study the influence of sleep circadian patterns in a highly admixed rural population with a conservative lifestyle. Here, we studied 786 subjects (mean age±SD 46.5±16.2, 42% female). Blood samples were collected from all participants. The Per3 length polymorphism was genotyped using PCR followed by gel electrophoresis. We tested for associations between the PER3 polymorphism and sleep characteristics, daytime sleepiness, and chronotype using the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Morningness-Eveningness Questionnaire, respectively. Depressive symptoms were assessed using the Beck Depression Inventory [BDI-II]). Results Our genotyping data showed that 36% of the subjects were homozygous for the shorter allele (4/4), 51% of the participants were heterozygous (4/5) and 12% of the subjects were homozygous for the longer allele (5/5). Allele frequency was 0.62 for the 4-repeat and a 0.38 for the 5-repeat. The percentages of the chronotypes Morning type (M-type), Neither type (N-type) and Evening type (E-type) were 5%, 46% and 7%, respectively. We observed an increase of the depression symptoms in evening types [F(2, 1014)=4.8, p=0.007]. On the other hand, no such associations were observed the PER3 genotype. There were no significant differences in the MEQ score [F(2, 317)=0.46, p=0.63], daytime sleepiness [(F(2, 317)=0.23, p=0.79)], sleep efficiency [(F(2, 317)=2.59, p=0.07)] and sleep characteristics [(F(2, 317)=1.92, p=0.14)] between the PER3 genotypes. Discussion We observed an association between eveningness and depression. Identifying factors contributing to individual differences in sleep and to describe how these factors are associated with physiological and psychological profiles may aid our understanding of the role of sleep and the circadian system in mental health. On the other hand, we were not able to replicate the association between the PER3 VNTR polymorphism and chronotype, which has been confirmed independently in multiple populations worldwide (including in Brazil). Neither did we observe any association with depression. CNPq – PVE 400791/2014-5.

0692 AGE AND GENDER DIFFERENCES AND CORRELATES OF MORNING-EVENINGNESS AMONG ADOLESCENTS IN PAKISTAN

Delayed sleep phase syndrome (DSPS) is an abnormal delay of major sleep period in relationship to the desired clock time often thought to originate in adolescence. A delay of sleep has been reported for teenagers in many countries across several continents, but inconsistent results are reported regarding gender differences in sleep pattern timing. We investigated the morningness/eveningness preferences of adolescents in Pakistan and its consequences on mood and functioning level. One thousand Pakistani adolescent students from private schools (Age range: 8–20; mean age: 14.9 years, SD: 1.49; 497 girls) participated in the study. They completed Children’s Morningness-Eveningness Preferences (CMEP) scale,(Carskadon 1993) and Short Mood and Feeling Questionnaire (SMFQ) (Angold and Costello 1987). Information about demographics, sleep habits, bedtime routine, and absences from school in the last month were obtained. We also collected information about presence or absence of cell phones, video games and television use in bedrooms. Mean CMEP scores were 29.78 (5.53) with 17.2% of the sample falling in the evening category, 39.8% in the morning category and 43% in neither category. Analysis of variance was used to compare grouping variables on CMEP scores. Males had significantly higher scores (greater morningness) than females (31.4 (5.2) vs 28.1 (5.4), [F(1,966=97.78), p <.001]. Examining CMEP categories, we found 65.1% of those in the Evening category were females whereas 67.3% of those in the Morning category were males (χ2=78.3, p<.001). Greater proportion of those in the evening category had cell phones (87%) compared to neither (79.3%) and morning (77.1%). Video games presence in the bedroom (F(1,970)=16.14, p=.017) and habitual snoring was associated with eveningness. There were more school absences (last month) in the evening category (2.25) vs (1.31) in the morning or neither category,F(2,970)=6.32, p=.002. One difference between our data and most samples from North America and Europe is that the tendency for eveningness was greater in girls than boys. In addition, the association of eveningness with cell phone and video game availability was notable. Eveningness was also coupled to more school absences reported in the last month. N/A.

Are larks future-oriented and owls present-oriented? Age- and sex-related shifts in chronotype–time perspective associations

The chronotype (morningness/eveningness) relates to individual differences in circadian preferences. Time perspective (past, present, future) refers to the preference to rely on a particular temporal frame for decision-making processes and behavior. First evidence suggests that future time perspective is associated with greater morningness and present time perspective with greater eveningness. However, little is known about how chronotype–time perspective relationships may alter over the life span. This present study investigated links between chronotype and time perspective more thoroughly by taking age and sex into account as well. Seven hundred six participants aged between 17 and 74 completed German adaptations of the Morningness--Eveningness Questionnaire (MEQ) and Zimbardo Time Perspective Inventory (ZTPI). Controlling for age and sex, relationships between morningness and future time perspective as well as between eveningness and present time perspective were replicated. These findings were supported by significant associations between time perspective and midpoint of sleep. Future time perspective was linked to earlier midpoints of sleep, indicating an early chronotype. Present time perspective was associated with later midpoints of sleep, indicating a late chronotype. However, age and sex had an impact on the chronotype–time perspective relationships. In all age groups, male larks were more future-oriented and less present-oriented, male owls more present-oriented and less future-oriented. The same conclusion could be drawn for female adolescents and young adults. For female adults above 30, there was no interrelationship between morningness and future time perspective but between eveningness and past time perspective. Female adult owls were more present-oriented as well as more past-oriented. Female adult larks were less present-oriented and less past-oriented. Findings are discussed in the light of neuroendocrine and serotonergic functioning.

Differential impact of chronotype on weekday and weekend sleep timing and duration

Most recommendations are that adults should obtain 7–8 hours of sleep per night, although there are individual differences in self-reported sleep need. Chronotype (preference for early or late sleep timing), in combination with social demands, may affect the ability to obtain adequate sleep. This questionnaire study assessed perceived sleep need and self-reported sleep timing and duration during the week and on the weekend with respect to chronotype in visitors to the Museum of Science in Boston. Increasing age was associated with greater morningness. After adjusting for age, we found no significant association between chronotype and self-reported sleep need, or between chronotype and weekday sleep duration. However, we did find that greater eveningness was associated with a larger gap between self-reported sleep need and weekday sleep duration. On weekends, greater eveningness was associated with a longer sleep duration and greater extension of sleep, with the sleep extension achieved by later wake times. Together, these findings suggest that evening types accumulate a sleep debt during the week, despite reporting a similar sleep need and duration as morning types, and evening types then attempt to make up for that lost weekday sleep on the weekends. Studies of sleep need and sleep duration should take chronotype into account, and studies of chronotype may be confounded by the association between age and morningness, and must account for this potential confound in selection criteria and/or analysis.

Rhythmicity and response to a.m. and p.m. CRH challenge in elderly subjects

—Cortisol and ACTH exhibit circadian rhythmicity, peaking in the early morning. These peaks are associated with increased activity and alertness. We sought to determine whether self-reported daily rhythms predict outcome of a.m. and p.m. CRH challenge in elderly subjects. We surveyed 96 elderly subjects to determine daily rhythms in activity levels, mood, alertness, and performance. Seven healthy subjects were given a cumulative activity score reflecting propensity toward morningness or eveningness. Subjects underwent CRH challenge testing during the morning and evening hours of different days. Baseline plasma ACTH and cortisol concentrations were higher in the morning than in the evening and lower values were associated with lower activity scores (i.e., greater morningness). No trends were apparent between activity score and net hormone response or percent change in hormone concentration.