Morningness-eveningness and sleep habits among adolescents : Age and gender differences.

Resumen tomado de la publicaci??n

Morningness-eveningness and anxiety among adults: A matter of sex/gender?

People’s health and well-being may be determined by the interaction of endogenous and external rhythms. Late chronotypes should become anxious because of the demand to perform tasks in a society oriented preferentially to morning work. In this study, we examined the relationship between morningness and anxiety in 559 adults (age range 40–63 years) from rural environments who completed morningness–eveningness and anxiety measures. Results indicated a negative correlation between morningness and anxiety in women, but not in men, suggesting the relevance of gender-related variables. When demographic characteristics were considered, women’s anxiety was predicted by low educational level and eveningness, whereas men’s anxiety was predicted by being single, having children, being unemployed, and eveningness. Some hypotheses of gender-related social roles are postulated as a possible explanation of the results.

Morningness-eveningness and sleep habits among adolescents: age and gender differences

Previous research has indicated the need to use large samples in different cultural contexts in order to clarify age and gender differences on morningness-eveningness and sleep habits. The goal of our research was to study the relationship between morningness-eveningness and sleep habits in a large sample of 2,649 adolescents between 12 and 16 years. The Morningness- Eveningness Scale for Children and an adaptation of the School Sleep Habits Survey measures were used. Results indicated a greater tendency toward eveningness with age and higher eveningness in 13- and 14-year-old girls. Older adolescents claimed later rising time on weekends, later bedtime and shorter sleep length, and greater social jetlag, weekend rise time delay, and weekend bedtime delay. Girls reported earlier rising time on weekdays, later rising time on weekends, longer sleep length on weekends, and greater social jetlag and weekend rising time delay. Lastly, evening oriented adolescents claimed later rising time and bedtime, shorter sleep length on weekdays but longer sleep duration on weekends, and greater social jetlag, weekend rising time delay, and weekend bedtime delay.

Transcultural properties of the Composite Scale of Morningness: The relevance of the "morning affect" factor

Morningness scales have been translated into several languages, but it lack of normative data and methodological differences make cross-cultural comparisons difficult. This study examines the psychometric properties and factor structure of the Composite Scale of Morningness (CSM) in samples from five countries: France (n = 627), Italy (n, = 702), Spain (n = 391), Thailand (n. = 503), and Australia (17 = 654). Strong national differences are identified. A quadratic relationship between age and CSM total score was apparent in the Australian data with a downward trend after age 35 yrs. There was no age effect in air), sample in the range from 18 to 29 yrs. Factor analysis identified a three-factor solution in all groups for both men and women. Tucker's congruence coefficients indicate that: (1) this solution is highly congruent between sexes in each culture, and (2) a morning affect factor is highly congruent between cultures. These results indicate there are national differences in factorial structure and that cut-off scores used to categorize participants as morning- and evening-types should be established for different cultural and age groups.

Morningness-eveningness orientation, optimal time-of-day and attitude change: Evidence for the systematic processing of a persuasive communication

This study investigates the effects of morningness-eveningness orientation and time-of-day on persuasion. In an attitude change paradigm, 120 female participants read a persuasive message that consisted of six counter-attitudinal arguments (anti-voluntary euthanasia) either in the morning (8:30 a.m.) or in the evening (7:00 p.m.). Attitude change was assessed by measuring attitudes towards the target issue before and after exposure to the message. Message processing was assessed by thought-listing and message recall tasks. Self-reported mood and arousal were monitored throughout. Participants were classified into M- and E-types according to their scores on the Horne and Ostberg (1976) MEQ questionnaire. When tested at their respective optimal time-of-day (i.e., morning for M-types/evening for E-types), M- and E-types reported higher energetic arousal, greater agreement with the message, greater message-congruent thinking, and a propensity for superior message recall compared to M- and E-types tested at their nonoptimal time-of-day (i.e., evening for M-types/morning for E-types). The attitude change in those tested at their optimal time-of-day was mediated by the level of message-congruent thinking. Results are interpreted in terms of the Elaboration Likelihood Model of persuasion. (c) 2005 Elsevier Ltd. All rights reserved.

Morningness-eveningness orientation and attitude change:evidence for greater systematic processing and attitude change at optimal time-of-day

This study examines the relationship between morningness-eveningness orientation and time-of day on attitude change, and tests the hypothesis that people will be more persuaded when tested at their optimal time-of-day (i.e., morning for M-types and evening for E-types) than non-optimal time-of-day (i.e., evening for M-Types and morning for E-types). Two hundred and twenty participants read a message that contained either strong vs. weak quality counter-attitudinal arguments (anti-voluntary euthanasia) in the morning (9.00. a.m.) or in the evening (7.00. p.m.). When tested at their respective optimal time-of-day (for both M- and E-types) there was a reliable difference in attitude change between the strong vs. weak messages (indicating message processing had occurred) while there was no difference between strong vs. weak messages when tested at their non-optimal time-of-day. In addition, the amount of message-congruent thinking mediated the attitude change. The results show that M- and E-types pay greater attention to and elaborate on a persuasive message at their optimal time-of-day, and this leads to increased attitude change, compared to those tested at their non-optimal time-of-day. © 2012.

Student morningness-eveningness type and performance:does class timing matter?

Circadian rhythms have often been linked to people’s performance outcomes, although this link has not been examined within the context of University students. We therefore sought to test whether students’ perceptions of their morning-evening (ME) type had an influence on their performance on modules. We tested this hypothesis using students from a number of modules at two UK Universities. Results indicated that, contrary to our hypothesis, the further the discrepancy between a student’s ME type and the teaching time of the class, the better the student’s performance. These results have implications for teaching as student ME type could be taken into account for timetabling especially if modules need to be taught multiple times. We also provide implications for those seeking to measure ME, as our results are consistent with a 5-item ME scale, a 3-item ME scale, and a single-item ME scale.

Morningness-eveningness and sociosexuality: Evening females are less restricted than morning ones

Sociosexual orientation is a construct describing the propensity to engage in casual sex and sexual activity in uncommitted relationships, varying from restricted to unrestricted orientation. The personality profile of people exhibiting unrestricted sociosexuality matches a personality profile related to eveningness. Previous research on sociosexuality and morningness–eveningness is scarce, however, and conducted only with male participants. The present study aimed at testing whether eveningness is related to unrestricted sociosexuality in both genders. Participants were 352 (62.8% female) Poles aged between 17 and 57. They completed the reduced morningness–eveningness Questionnaire and the revised Sociosexual Orientation Inventory, consisting of three facets: behavior, attitude, and desire. The results revealed that females were more restricted than males in all facets of sociosexuality. Moreover, in both genders older age was related to less restricted behavior and attitude. Analyses showed that morningness– eveningness was unrelated to sociosexuality in males, but in females eveningness was linked to less restricted global sociosexuality .Eveningness in females could be regarded as a contributory factor to the instability of romantic relationships and high-risk sexual behaviors.

Melatonin synthesis : a possible indicator of intolerance to shiftwork

Hypothesis Melatonin synthesis, which is directly controlled by the central circadian pacemaker indicates the circadian phase better than rectal temperature. Methods: Thirty four men (16-32 years, 7 morning, 13 neither, 14 evening types) performed a constant routine (24-26-hr bedrest, < 30 lux, 18-20°C, hourly isocaloric diet). Salivary melatonin level was determined hourly and rectal temperature was continuously recorded. Results: The nadir of rectal temperature occurred 1.5 hr (P = 0.017), the onset of melatonin synthesis 3 hr earlier (P < 0.0001) in morning than in evening types. Morningness was not related to the quantitative but significantly to the temporal parameters, closer to those of melatonin than of rectal temperature. Conclusions: The melatonin onset is a more reliable indicator of the diurnal type than the nadir of rectal temperature. As morningness has been associated with intolerance to shiftwork, melatonin profiling provides a suitable basis for the establishment of directed preventive measures.

Circadian Rhythm Disruptions and Health

The doctoral thesis defined connections between circadian rhythm disruptions and health problems. Sleep debt, jet-lag, shift work, as well as transitions into and out of the daylight saving time may lead to circadian rhythm disruptions. Disturbed circadian rhythm causes sleep deprivation and decrease of mood and these effects may lead to higher accident rates and trigger mental illnesses. Circadian clock genes are involved in the regulation of the cell cycle and metabolism and thus unstable circadian rhythmicity may also lead to cancer development. In publications I-III it was explored how transitions into and out of the daylight saving time impact the sleep efficiency and the rest-activity cycles of healthy individuals. Also it was explored whether the effect of transition is different in fall as compared to spring, and whether there are subgroup specific differences in the adjustment to transitions into and out of daylight saving time. The healthy participants of studies I-III used actigraphs before and after the transitions and filled in the morningness-eveningness and seasonal pattern assessment questionnaires. In publication IV the incidence of hospital-treated accidents and manic episodes was explored two weeks before and two weeks after the transitions into and out of the daylight saving time in years 1987-2003. In publication V the relationship between circadian rhythm disruption and the prevalence of Non-Hodgkin lymphoma was studied. The study V consisted of all working aged Finns who participated in the national population census in 1970. For our study, all the cancers diagnosed during the years 1971-1995 were extracted from the Finnish Cancer Register and linked with the 1970 census files. In studies I-III it was noticed that transitions into and out of the daylight saving time disturbs the sleep-wake cycle and the sleep efficiency of the healthy participants. We also noticed that short sleepers were more sensitive than long sleepers for sudden changes in the circadian rhythm. Our results also indicated that adaptation to changes in the circadian rhythm is potentially sex, age and chronotype-specific. In study IV no significant increase in the occurrence of hospital treated accidents or manic episodes was noticed. However, interesting observations about the seasonal fluctuation of the occurrence rates of accidents and manic episodes were made. Study V revealed that there might be close relationship between circadian rhythm disruption and cancer. The prevalence of Non-Hodgkin lymphoma was the highest among night workers. The five publications included in this thesis together point out that disturbed circadian rhythms may have adverse effect on health. Disturbed circadian rhythms decrease the quality of sleep and weaken the sleep-wake cycle. A continuous circadian rhythm disruption may also predispose individuals to cancer development. Since circadian rhythm disruptions are common in modern society they might have a remarkable impact on the public health. Thus it is important to continue circadian rhythm research so that better prevention and treatment methods can be developed. Keywords: Circadian rhythm, daylight saving time, manic episodes, accidents, Non-Hodgkin lymphoma 11

Very Low Birth Weight Infants as Young Adults : Focus on aspects of cognition, behavior and sleep

Major advances in the treatment of preterm infants have occurred during the last three decades. Survival rates have increased, and the first generations of preterm infants born at very low birth weight (VLBW; less than 1500 g) who profited from modern neonatal intensive care are now in young adulthood. The literature shows that VLBW children achieve on average lower scores on cognitive tests, even after exclusion of individuals with obvious neurosensory deficits. Evidence also exists for an increased risk in VLBW children for various neuropsychiatric disorders such as attention-deficit hyperactivity disorder (ADHD) and related behavioral symptoms. Up till now, studies extending into adulthood are sparse, and it remains to be seen whether these problems persist into adulthood. The aim of this thesis was to study ADHD-related symptoms and cognitive and executive functioning in young adults born at VLBW. In addition, we aimed to study sleep disturbances, known to adversely affect both cognition and attention. We hypothesized that preterm birth at VLBW interferes with early brain development in a way that alters the neuropsychological phenotype; this may manifest itself as ADHD symptoms and impaired cognitive abilities in young adulthood. In this cohort study from a geographically defined region, we studied 166 VLBW adults and 172 term-born controls born from 1978 through 1985. At ages 18 to 27 years, the study participants took part in a clinic study during which their physical and psychological health was assessed in detail. Three years later, 213 of these individuals participated in a follow-up. The current study is part of a larger research project (The Helsinki Study of Very Low Birth Weight Adults), and the measurements of interest for this particular study include the following: 1) The Adult Problem Questionnaire (APQ), a self-rating scale of ADHD-related symptoms in adults; 2) A computerized cognitive test battery designed for population studies (CogState®) which measures core cognitive abilities such as reaction time, working memory, and visual learning; 3) Sleep assessment by actigraphy, the Basic Nordic Sleep Questionnaire, and the Morningness-Eveningness Questionnaire. Actigraphs are wrist-worn accelerometers that separate sleep from wakefulness by registering body movements. Contrary to expectations, VLBW adults as a group reported no more ADHD-related behavioral symptoms than did controls. Further subdivision of the VLBW group into SGA (small for gestational age) and AGA (appropriate for gestational age) subgroups, however, revealed more symptoms on ADHD subscales pertaining to executive dysfunction and emotional instability among those born SGA. Thus, it seems that intrauterine growth retardation (for which SGA served as a proxy) is a more essential predictor for self-perceived ADHD symptoms in adulthood than is VLBW birth as such. In line with observations from other cohorts, the VLBW adults reported less risk-taking behavior in terms of substance use (alcohol, smoking, and recreational drugs), a finding reassuring for the VLBW individuals and their families. On the cognitive test, VLBW adults free from neurosensory deficits had longer reaction times than did term-born peers on all tasks included in the test battery, and lower accuracy on the learning task, with no discernible effect of SGA status over and above the effect of VLBW. Altogether, on a group level, even high-functioning VLBW adults show subtle deficits in psychomotor processing speed, visual working memory, and learning abilities. The sleep studies provided no evidence for differences in sleep quality or duration between the two groups. The VLBW adults were, however, at more than two-fold higher risk for sleep-disordered breathing (in terms of chronic snoring). Given the link between sleep-disordered breathing and health sequelae, these results suggest that VLBW individuals may benefit from an increased awareness among clinicians of this potential problem area. An unexpected finding from the sleep studies was the suggestion of an advanced sleep phase: The VLBW adults went to bed earlier according to the actigraphy registrations and also reported earlier wake-up times on the questionnaire. In further study of this issue in conjunction with the follow-up three years later, the VLBW group reported higher levels of morningness propensity, further corroborating the preliminary findings of an advanced sleep phase. Although the clinical implications are not entirely clear, the issue may be worth further study, since circadian rhythms are closely related to health and well-being. In sum, we believe that increased understanding of long-term outcomes after VLBW, and identification of areas and subgroups that are particularly vulnerable, will allow earlier recognition of potential problems and ultimately lead to improved prevention strategies.

Ritmos biológicos, cronotipo e funções cognitivas : um estudo de campo

Os primeiros estudos onde se tentava avaliar os melhores horários para se lecionar de forma a se poderem otimizar os horários escolares são já muito antigos. O primeiro a estabelecer uma relação sistemática entre performance cognitiva, Cronobiologia e sono foi Kleitman, evidenciando uma paralelismo entre o ritmo circadiano da temperatura central e a altura do dia em que eram realizadas tarefas simples de repetição. Após este primeiro estudo, muitos outros se seguiram, contudo a maioria apenas encontrou ritmos em protocolos de rotina constante e dessincronização forçada desprovidos de validade ecológica. Acresce ainda o facto de neste tipo de estudos não haver uma manipulação sistemática do efeito do padrão individual de distribuição dos parâmetros circadianos no nictómero, designado na literatura como Cronotipo. Perante isto, o presente estudo pretende avaliar a influência do Cronotipo nos ritmos cognitivos, utilizando um protocolo de rotina normal (Ecológico), onde também se manipula o efeito fim-de-semana. Para testar as premissas supramencionadas, utilizou-se uma amostra de 16 alunos universitários, que numa primeira fase responderam ao questionário de Matutinidade e Vespertinidade de Horne&Östberg, para caracterização do Cronotipo, e posteriormente andaram 15-17 dias consecutivos com tempatilumis (actímetros) para análise de ritmos de temperatura e atividade, com iPads onde realizavam ao longo do dia várias tarefas cognitivas e com o Manual de Registo Diário, onde respondiam ao diário de sono e de atividade. A análise de dados denotou a inexistência de expressão de ritmos na maioria dos parâmetros cognitivos inviabilizando a verificação de diferenças significativas entre indivíduos matutinos e vespertinos nestes parâmetros. Esta ausência de visualização da expressão rítmica pode ser explicada pelo facto de os participantes não terem aderido da forma desejada e exigida, à realização das tarefas cognitivas, ou pelo facto de termos usado um protocolo de rotina normal, em detrimento dos protocolos de rotina constate e dessincronização forçada, não controlando assim algumas variáveis que influenciam o desempenho cognitivo, podendo estas mascarar ou mesmo eliminar o ritmo. Ainda assim e apesar destas contingências observaram-se ritmos circadianos nas variáveis de autoavaliação, mesmo com o paradigma ecológico. Verificou-se ainda um efeito da hora do dia em vários parâmetros de tarefas cognitivas e motoras medidas objetivamente, assim como uma diminuição da performance cognitiva nos vespertinos, comparativamente aos matutinos, na janela temporal das 6h às 12 horas, que coincide com a maior concentração de horas de aulas por dia na Universidade onde o estudo foi realizado. Outros estudos serão necessários para consolidar a influência do Cronotipo nos ritmos cognitivos, utilizando o protocolo de rotina normal para garantir a validade ecológica, salvaguardando uma participação mais ativa na execução das tarefas cognitivas por parte dos sujeitos em estudo.

Medical Students Circadian Sleep Rhythms and Academic Performance

Objective: to evaluate, with a preliminary study, the distribution of circadian rhythms, sleep schedule patterns and their relationship with academic performance on medical students. Methodology: in this descriptive study, a 10 item original questionnaire about sleep rhythms and academic performance was applied to medical students from different semesters. Week (class time) and weekend schedules, preferences, daytime somnolence and academic performance were asked. Three chronotypes (morningness, intermediate and eveningness) were defined among waking-sleeping preference, difficulty to sleep early, exam preparation preference hour and real sleep schedule. The sleep hour deficit per week night was also calculated. Results: Of the 318 medical students that answered the questionnaire, 62.6% corresponded to intermediate chronotypes, 8.8% to evening-type and 28.7% to morning-type. Significant difference was found among the two chronotype tails (p=0.000, Chi-square 31.13). No correlation was found between academic performance and age, sex, chronotype, week sleep deficit and sleep hours in week and weekends. A 71.1% of the students slept 6 or fewer hours during class time and 78% had a sleep deficit (more frequent in the evening chronotype). Conclusions: No relation was found between sleep chronotype and academic performance. Students tend to morningness. Few studies have been made on equatorial zones or without seasons

Do Circadian Preferences Influence the Sleep Patterns of Night Shift Drivers?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Job satisfaction and discrepancies between social and biological timing

The discrepancies between social and biological timing are reflected in shift workers' well-being. The aim of this study was to verify the association between job satisfaction and chronotype among day and night nursing personnel. Several variables, including seniority at the hospital and, in the same shift, sleep duration, quality of sleep, sleepiness and willingness to change sleep timing were also analyzed. Chronotype was calculated by using the morningness-eveningness questionnaire. We studied 514 nursing professionals from a public university hospital. Among the day workers, the higher the morningness, the more the workers were satisfied with their job. In contrast, among night workers, job satisfaction was associated with sleep quality and seniority at the hospital but not with chronotype. Our results suggest that an agreement between work schedule and chronotype may help to increase job satisfaction among diurnal workers.