Morningness–eveningness interferes with perceived health,physical activity,diet and stress levels in working women: A cross-sectional study

Sleep and health are closely interrelated and sleep quality is a well-known contributor to perceived health. However, effects of sleep-timing preference i.e. morningness–eveningness on health has yet to be revealed. In this study, we explored the relationship between morningness–eveningness and perceived health in a sample of female working professionals (N?=?202). Sleep-timing preference was measured using the Composite Scale of Morningness. Perceived health was characterized by Center for Epidemiologic Studies Depression Scale, WHO Well-Being Scale-5 and Patient Health Questionnaire-15 scores. We also investigated possible mechanisms, including stress and health-impairing behaviours. In accordance with previous data, we found more depressive mood, lower well-being and poorer perceived health among evening types. To assess health-impairing behaviours we collected data on smoking habits, alcohol consumption, physical activity and diet. Among the possible mechanism variables, greater stress, less frequent physical activity and less healthy diet were associated with eveningness. Furthermore, stress diminished the strength of the association between morningness–eveningness and depressed mood. Physical activity attenuated the strength of the association between morningness–eveningness and well-being. No effects of alcohol consumption could be identified. Our data show that evening preference behaves as a health risk in terms of associating with poor perceived health. Our findings also suggest that this effect might be mediated by health behaviours and stress.     

Angry night birds: Emotionality,activity and sociability temperament in adolescent chronotypes

ABSTRACT

There is growing interest in personality profiles associated with morningness–eveningness to foster an understanding of the behaviors and mental states of chronotypes. This study aimed to analyze the domains of emotionality, activity and sociability (EAS) temperament in relation to morningness–eveningness in adolescents. A sample of 539 school pupils aged 13–19 years completed the EAS Temperament Survey, the Composite Scale of Morningness and the Munich Chronotype Questionnaire. Amongst the five EAS domains (emotionality-distress, emotionality-fearfulness, emotionality-anger, activity and sociability), greater emotionality-anger was related to eveningness, while greater emotionality-distress was related to lower social jet lag. The results suggest that evening chronotypes can be temperamentally inclined to anger. The possible mechanisms of this association are discussed.     

Correlation between morningness-eveningness and final school leaving exams

Pupils shift their time of day preferences from morningness to eveningness during the age of puberty. Therefore, early school start times may have a negative influence on school functioning, adolescent health and on grade point average. Here, we show that morningness - eveningness influences school performance as measured by the final school leaving/university entrance certificate. One hundred and thirty-two university students aged between 20 and 22 years participated in our study. We found a highly significant positive correlation between the average grading of the final exam and the morningness score, suggesting that pupils with morning preferences performed better in school achievement. Evening types seem at a serious disadvantage because the final exams are used for university entrance decisions.     

PARENTAL ENFORCEMENT OF BEDTIME DURING CHILDHOOD MODULATES PREFERENCE OF JAPANESE JUNIOR HIGH SCHOOL STUDENTS FOR EVENINGNESS CHRONOTYPE

We examined the effect of home bedtime discipline during childhood on morningness and eveningness (M-E) preference by Japanese junior high school students. M-E was assessed by the M-E Questionnaire (MEQ) of Torsvall and Åkerstedt (the higher the score, the greater the preference for morningness), and parental determination of bedtime during childhood was ascertained using an original questionnaire. The average M-E score of adolescents living in urban Kochi City (mean ± SD; 15.10 ± 3.42) was significantly lower (P <. 01) than the score of those in suburban districts (16.14 ± 3.44). Overall, 43.1% of the junior high school students in Kochi City compared to 53.0% of the students living in suburban districts had their bedtime decided during childhood by parents (P <. 01). In Kochi City, the M-E score for boys (14.62 ± 3.51) was lower (P <. 01) than girls (15.53 ± 3.28). During childhood, parents decided the bedtime for 49% of the girls compared to 36.6% of the boys (P <. 01). Boys whose bedtime was not decided by parents during childhood had a somewhat stronger preference for eveningness (14.20 ± 3.53) (P <. 05) compared to those whose bedtime was decided by parents (15.12 ± 3.36). The results suggest bedtime discipline at home during childhood has an effect on adolescent chronotype, modulating the extent of shift to eveningness in Japanese junior high school boys in particular. (Chronobiology International, 18(5), 823–829, 2001)     

Chronotype correlates with developmental index,intelligence and academic achievement: A study based on nationwide indicators

Chronotype or morningness–eveningness (M/E) is an individual trait with a biological basis. In this study, I analysed the relationship between M/E and nationwide available data, such as economic variables, school achievement, intelligence and conscientiousness, which is a personality trait. These variables have been chosen because, first, they are linked on the individual level with circadian preference, and, second these associations have been found based on meta-analyses, which gives these findings a high plausibility. In addition, economic status has also been proposed to be related to M/E. Higher developed countries showed a lower morningness, based on both, the ranking of countries as well as on the HDI value. Similarly, GNI was related to morningness, while higher intelligence and performance in PISA were related to eveningness. Conscientiousness was related to morningness, although the results failed the significance level marginally. When using IQ as a control variable in partial correlations, the relationship between GNI and morningness disappeared, as did the correlation between eveningness and PISA results.     

Parental enforcement of bedtime during childhood modulates preference of Japanese junior high school students for eveningness chronotype.

We examined the effect of home bedtime discipline during childhood on morningness and eveningness (M-E) preference by Japanese junior high school students. M-E was assessed by the M-E Questionnaire (MEQ) of Torsvall and Akerstedt (the higher the score, the greater the preference for morningness), and parental determination of bedtime during childhood was ascertained using an original questionnaire. The average M-E score of adolescents living in urban Kochi City (mean +/- SD; 15.10 +/- 3.42) was significantly lower (P < .01) than the score of those in suburban districts (16.14 +/- 3.44). Overall, 43.1% of the junior high school students in Kochi City compared to 53.0% of the students living in suburban districts had their bedtime decided during childhood by parents (P < .01). In Kochi City, the M-E score for boys (14.62 +/- 3.51) was lower (P < .01) than girls (15.53 +/- 3.28). During childhood, parents decided the bedtime for 49% of the girls compared to 36.6% of the boys (P < .01). Boys whose bedtime was not decided by parents during childhood had a somewhat stronger preference for eveningness (14.20 +/- 3.53) (P < .05) compared to those whose bedtime was decided by parents (15.12 +/- 3.36). The results suggest bedtime discipline at home during childhood has an effect on adolescent chronotype, modulating the extent of shift to evening ness in Japanese junior high school boys in particular.     

Changes in growth and sleep across school nights,weekends and a winter holiday period in two Australian schools

Studies suggest that there may be an association between sleep and growth; however, the relationship is not well understood. Changes in biology and external factors such as school schedule heavily impact the sleep of adolescents, during a critical phase for growth. This study assessed the changes in sleep across school days, weekends and school holidays, while also measuring height and weight changes, and self-reported alterations in food intake and physical activity. The impact of morningness–eveningness (M-E) on height change and weight gain was also investigated. In a sample of 63 adolescents (mean age = 13.13, SD = 0.33, 31 males) from two independent schools in South Australia, height and weight were measured weekly for 4 weeks prior to the school holidays and 4 weeks after the school holidays. Participants also completed a Morningness/Eveningness Scale and 7-day sleep, diet and physical activity diaries prior to, during and after the school holidays. Participants at one school had earlier wake times during the weekends than participants attending the other school, leading to a significantly shorter sleep duration on weekends for those participants. Regardless of school, sleep was significantly later and longer during the holidays (p < 0.001) and those with a stronger morning preference fell asleep (F_18,36 = 3.4, p = 0.001) and woke (F_18,44 = 2.0, p = 0.027) earlier than evening types. Growth rate was lower during the holiday weeks. For those attending the school with limited sleep in opportunities, growth after the holidays was lower for those with greater evening preference, whereas for those at the other school, growth was greater for those with greater evening preference. The increase in average weight from pre- to post-holidays was greater for those attending the school with limited opportunities to sleep longer. Participants reported greater food intake during the holidays compared to school days and greater physical activity levels on weekends compared to school days, and school days compared to holidays. Results suggest that time of day preference may impact growth, with evening types who cannot sleep in growing at a slower rate than evening types who can or morning types. This may be related to sleep restriction. Despite sleep being both later and longer during the school holidays, participants’ growth slowed during the holiday period. It is possible that this may be a reflection of other behavioural changes in the holidays (increased food intake and reduced physical activity), as sleep timing during the school period was related to growth.     

Clinical correlates of chronotypes in young persons with mental disorders

While important changes in circadian rhythms take place during adolescence and young adulthood, it is unclear how circadian profiles during this period relate to emerging mental disorders. This study aimed to: (i) characterise morningness–eveningness preference in young people with primary anxiety, depression, bipolar or psychotic disorders as compared to healthy controls, and (ii) to investigate associations between morningness–eveningness preference and the severity of psychiatric symptoms. Four hundred and ninety-six males and females aged between 12 and 30 years were divided into five groups according to primary diagnosis. The Hamilton Depression Rating Scale and the Brief Psychiatric Rating Scale were administered by a research psychologist and participants completed the Kessler Psychological Distress Scale and the Horne–Östberg Morningness–Eveningness Questionnaire (ME). ME scores were significantly lower (i.e. higher levels of “eveningness”) in all patient diagnosis subgroups compared to the control group. The psychosis group had higher ME scores than the depression and anxiety groups. Compared to the control group, the anxiety, depression and bipolar subgroups had a significantly higher proportion of “moderate evening” types, with a similar trend for the psychosis group. The proportion of “extreme evening” types was significantly higher in the anxiety and depression subgroups than in the control group. Lower ME scores correlated with worse psychological distress in males from the bipolar group. Lower ME scores correlated with higher depression severity in females with depression and in males with bipolar disorder. These results suggest that young persons with various mental disorders, especially those with affective disorders, present with a stronger “eveningness” preference and higher rates of evening chronotypes than healthy controls from the same age group. Later chronotypes were generally associated with worse psychological distress and symptoms severity. These associations were modulated by sex and primary diagnosis.     

Positive and negative affect during the school day and its relationship to morningness–eveningness

We carried out a field study in adolescents in a German school to assess their actual affective state during the first and last lesson of a school day. Also, we wanted to assess if chronotype or sleep duration has an influence on affect. One hundred and nine girls and 110 boys participated in the study (mean age: 14.47). The composite scale of morningness (CSM) was used to assess morningness–eveningness and the positive and negative affect schedule (PANAS) was used for affect measurement. Sleep habits were assessed as both, habitual and actual sleep–wake rhythm. Positive affect (PA) was higher in the sixth lesson compared to the first one, but negative affect (NA) was not. CSM scores were positively correlated with PA during the first and last lesson. The correlation coefficient was higher in the first lesson of the day. NA was unrelated to CSM scores. Pupils with a shorter actual sleep duration had a higher NA. Habitual sleep duration was unrelated to affect measures. The results showed no synchrony effect; thus, evening types have still a lower PA in the last lesson than morning types. We emphasise the importance of mood and its relationship with morningness in school children, and we hypothesise that this may also have an influence on functioning during the school day.     

The role of temperament in the relationship between morningness–eveningness and mood

Apart from differences in circadian phase position, individuals with different morningness–eveningness levels vary in many more characteristics. Particularly consistent relationships have been observed between morningness–eveningness and mood. Eveningness has been associated with disadvantageous mood, e.g. depressiveness in healthy individuals, and mood disorders. A concept of social jetlag suggests that evening subjects function in less advantageous environments due to discrepancies between internal and social time (societies promote morning-oriented functioning), which results in their lowered mood. Individual temperament, as defined by the Regulative Theory of Temperament (RTT), refers to the capacity of the human organism to meet environmental requirements – the greater the capacity, the less negative impact of external conditions. Thus, the aim of this study is to determine which RTT traits are linked to both morningness–eveningness and mood dimensions and to test whether they account for the relationship between morningness–eveningness and mood. A sample of 386 university students (267 female) aged between 19 and 47 (M?=?21.15, SD?=?4.23) years completed the University of Wales Institute of Science and Technology (UWIST) Mood Adjective Check List, Morningness–Eveningness Questionnaire and Formal Characteristics of Behaviour – Temperament Inventory. Analyses revealed lower endurance (EN) and higher emotional reactivity (ER) related to eveningness as well as to lower hedonic tone (HT), energetic arousal (EA) and to higher tense arousal (TA). Moreover, eveningness was associated with lower HT, EA and higher TA. Among RTT traits, EN was most strongly related to eveningness, and mediation analyses revealed that this temperamental trait fully mediated the relationship between eveningness and the three mood dimensions. The remaining RTT traits did not provide more explanation of the association between morningness–eveningness and mood than EN itself. If subjects did not differ in EN, the association between morningness–eveningness and mood was absent. EN is discussed as a protective factor against negative consequences of social jetlag and particularly lowered mood in evening individuals.     

Perceived morningness–eveningness predicts academic adjustment and substance use across university,but social jetlag is not to blame

Past research has consistently found that evening-types typically report poorer academic adjustment and higher levels of substance use compared to morning-types. An important development within the morningness–eveningness and psychosocial adjustment literature has been the hypothesis that social jetlag (i.e. the asynchrony between an individual’s “biological” and “social” clocks) is one factor that may explain why evening-types are at a greater risk for negative psychosocial adjustment. Yet, only a handful of studies have assessed social jetlag. Furthermore, the few studies that have assessed social jetlag have done so only with concurrent data, and thus have not been able to determine the direction of effects among morningness–eveningness, social jetlag and psychosocial adjustment. To address this important gap in the literature, the present 3-year longitudinal study employed the use of a cross-lagged auto-regressive model to specifically examine the predictive role of perceived morningness–eveningness and social jetlag on two important indices of psychosocial adjustment among university students: academic adjustment and substance use. We also assessed whether there would be an indirect effect between perceived morningness–eveningness and psychosocial adjustment through social jetlag. Participants were 942 (71.5% female; M?=?19 years, SD?=?0.90) undergraduates at a mid-sized university in Southern Ontario, Canada, who completed a survey at three assessments, each one year apart, beginning in first-year university. Measures were demographics (age, gender and parental education), sleep problems, perceived morningness–eveningness, social jetlag, academic adjustment and substance use. As hypothesized, results of path analyses indicated that a greater perceived eveningness preference significantly predicted higher social jetlag, poorer academic adjustment and higher substance use over time. In contrast, we found no support for social jetlag as a predictor of academic adjustment and substance use, indicating that social jetlag did not explain the link between perceived morningness–eveningness and negative psychosocial adjustment. An important finding was the significant predictive effect of higher substance use on social jetlag over time. Results of the present study highlight the importance of employing a longitudinal framework within which to specifically determine the direction of effects among the study variables in order to validate proposed theoretical models that aim to guide our understanding of how perceived morningness–eveningness, social jetlag, academic adjustment and substance use relate to each other.     

Morningness–eveningness and treatment response in major depressive disorder

In a large, prospective, 8-week open study of 721 outpatients receiving agomelatine treatment for a current major depressive episode (MDE), morningness–eveningness (Composite Scale of Morningness) was assessed before and after treatment to investigate possible changes in morningness–eveningness after treatment and evaluate whether morningness–eveningness at baseline predicted treatment response. A change towards morningness was observed after treatment. This change was greater in responders than non-responders. Moreover, being a morning type at baseline was an independent predictor of response to treatment. Once thought to be a trait variable, morningness–eveningness is a potential treatment target that should be systematically assessed in MDE patients.     

A pilot replication study of two PER3 single nucleotide polymorphisms as potential genetic markers for morning and evening earliness-lateness

Polymorphisms in genes of circadian system family seem to be of most importance for understanding of mechanisms underlying self-assessed individual variation in morning–evening preference. A review of earlier reported positive findings indicated that, at least, four polymorphisms in period circadian clock 3 (PER3) showed significant association with, at least, one of sub-constructs of a morningness–eveningness scale. However, similar to other candidate gene studies, these studies suffer from increased likelihood of false positive findings. We tried to replicate some of the most recently published positive results on associations of sub-traits of morningness–eveningness with two PER3 non-synonymous single nucleotide polymorphisms. DNA from buccal swabs was collected from healthy residents of three Russian cities, Moscow (N = 149) and Novosibirsk and Stavropol (N = 248). The tested hypotheses were formulated in accord with the earlier reported positive findings: the rare alleles might be linked to a higher score on (i) morning earliness–lateness scale (rs2640909, Moscow data-set) and (ii) both morning and evening earliness–lateness scales (rs228729, Novosibirsk and Stavropol datasets). The results provided support for the former hypothesis. These and earlier reported results highlighted several critical issues that remained to be addressed in future independent replications of positive findings on potential genetic markers for morning and evening earliness–lateness.     

Social jetlag,academic achievement and cognitive performance: Understanding gender/sex differences

Adolescents in high school suffer from circadian misalignment, undersleeping on weekdays and oversleeping on weekends. Since high schools usually impose early schedules, adolescents suffer from permanent social jetlag (SJL) and thus are a suitable population to study the effects of SJL on both academic and cognitive performance. In this study, 796 adolescents aged 12–16 years reported information about their sleep habits, morningness–eveningness (M–E), cognitive abilities and grade point average (GPA). Time in bed on both weekdays and weekends was not related to cognitive abilities, and only time in bed on weekdays was related to academic achievement. SJL was negatively related to academic achievement, cognitive abilities (except for vocabulary and verbal fluency abilities) and general cognitive ability (g), whereas M–E was slightly positively related to academic achievement and marginally negatively related to inductive reasoning. Results separated by sex/gender indicated that SJL may be more detrimental to girls’ performance, as it was negatively related to a greater number of cognitive abilities and GPA.     

CIRCADIAN RHYTHMICITY OF CORTISOL AND BODY TEMPERATURE: MORNINGNESS-EVENINGNESS EFFECTS

The purpose of this study was to describe and compare the circadian rhythm of body temperature and cortisol, as well as self-reported clock times of sleep onset and offset on weekdays and weekends in 19 healthy adult “larks” (morning chronotypes) and “owls” (evening chronotypes), defined by the Horne and Östberg questionnaire. Day-active subjects entered the General Clinical Research Center, where blood was sampled every 2h over 38h for later analysis for cortisol concentration by enzyme immunoassay. Rectal body temperature was measured continuously. Lights were turned off at 22:30 for sleep and turned on at 06:00, when subjects were awakened. The acrophases (peak times) of the cortisol and temperature rhythms occurred 55 minutes (P ≤.05) and 68 minutes (P <.01), respectively, earlier in the morningness group. The amplitude of the cortisol rhythm was lower in the eveningness than in the morningness group (P = n.s.). Subject groups differed on all indices of habitual and preferred timing of sleep and work weekdays and weekends (P =. 05–.001). (Chronobiology International, 18(2), 249–261, 2001)     

Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects

The purpose of this study was to describe and compare the circadian rhythm of body temperature and cortisol, as well as self-reported clock times of sleep onset and offset on weekdays and weekends in 19 healthy adult "larks" (morning chronotypes) and "owls" (evening chronotypes), defined by the Home and Ostberg questionnaire. Day-active subjects entered the General Clinical Research Center, where blood was sampled every 2 h over 38 h for later analysis for cortisol concentration by enzyme immunoassay. Rectal body temperature was measured continuously. Lights were turned off at 22:30 for sleep and turned on at 06:00, when subjects were awakened. The acrophases (peak times) of the cortisol and temperature rhythms occurred 55 minutes (P < or = .05) and 68 minutes (P < .01), respectively, earlier in the morningness group. The amplitude of the cortisol rhythm was lower in the eveningness than in the morningness group (P = n.s.). Subject groups differed on all indices of habitual and preferred timing of sleep and work weekdays and weekends (P = .05-.001).     

The effects of biological rhythms and sleep quality on benign paroxysmal positional vertigo and reflux symptom severity

Recently, there has been increased interest in chronotypes and clinical differences between them. However, there is limited information about the potential influence of the chronotypes on clinical manifestations and symptom intensity of somatic diseases. The aim of this study is to evaluate the impact of biological rhythm differences and sleep quality on benign paroxysmal positional vertigo (BPPV) and larengo pharyngeal reflux (LPR) severity. Forty-four LPR patients, 43 BBPV patients and 42 controls were included in the study. The morningness–eveningness questionnaire was used to determine chronotypes, and the Pittsburgh Sleep Quality Index was used to assess subjective sleep quality. Both patient groups reported a significantly greater tendency to eveningness diurnal preferences compared to healthy controls. As with the circadian preferences, patients with BPPV or LPR characterized by poorer sleep quality and worse insomnia than non-patient individuals. It can be concluded that the circadian rhythm and sleep quality are related to the severity of LPR and BPPV.     

Morningness–eveningness and sleep habits at school: a comparative study between Mexico and Spain

Morningness–eveningness and sleep habits relationship were studied between Mexican and Spanish adolescents. A total sample of 611 Mexican and Spanish adolescents (13–15 years old; 14.12 ± 0.75) participated in this comparative study and filled out the preferred timing of sleep and activity using item 19 of Morningness–Eveningness Questionnaire and reported sleep habits from open questions about typical bed and rise times during the weekdays and weekends. Spanish adolescents reported differences in sleep habits according to sex and chronotype, whereas Mexican adolescents only reported differences regarding chronotype on weekends. When country effect was analyzed, the most relevant result was the short sleep length on weekdays of Mexican adolescents (7:11 vs. 8:05), who reported earlier weekday rise time (6:11 vs. 7:15) but similar weekday bedtime (23:00 vs. 23:09) compared to Spanish adolescents. Sleep habits among Mexicans seem more influenced by a social factor related to school schedule than environmental factor related to latitude.     

Chronotype and its relationship with sleep disorders in children with attention deficit hyperactivity disorder

Chronotype can be classified as morningness types, people who prefer morning hours for their physical and mental activities; eveningness types, people who prefer the afternoon or evening hours; and intermediate types, those who show characteristics of both morningness and eveningness types. Attention deficit hyperactivity disorder (ADHD) has been linked with disturbances in chronotype, particularly increased eveningness. Despite the possibility of an association between chronotypes, sleep disturbances and ADHD symptoms, there is little evidence of this association considering the child population. The purpose of this study was to examine chronotype preferences in children aged between 7 and 12 years who were diagnosed as having ADHD in the context of sleep disturbances. The Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version, Conner’s Rating Scales, Children’s Sleep Habit Questionnaire and Children’s Chronotype Questionnaire were used for the evaluation of children with ADHD and healthy controls. The ADHD group was 73% combined-type, and the eveningness scores of the ADHD group (n = 52) were significantly higher than the control group (n = 52) (p < 0.01). There was a positive correlation between the higher scores of eveningness and total scores on resistance to sleep time (p < 0.09), respiratory problems during sleep and daytime sleepiness in the ADHD group. CSHQ total score was found to be a predictive factor for eveningness among children with ADHD (p < 0.01). These findings highlight possible reciprocal links between ADHD symptoms, sleep disturbances and chronotype in children aged 7–12 years, which might lead to individualized treatment options.     

The role of chronotype,gender, test anxiety,and conscientiousness in academic achievement of high school students

Previous findings have demonstrated that chronotype (morningness/intermediate/eveningness) is correlated with cognitive functions, that is, people show higher mental performance when they do a test at their preferred time of day. Empirical studies found a relationship between morningness and higher learning achievement at school and university. However, only a few of them controlled for other moderating and mediating variables. In this study, we included chronotype, gender, conscientiousness and test anxiety in a structural equation model (SEM) with grade point average (GPA) as academic achievement outcome. Participants were 158 high school students and results revealed that boys and girls differed in GPA and test anxiety significantly, with girls reporting better grades and higher test anxiety. Moreover, there was a positive correlation between conscientiousness and GPA (r = 0.17) and morningness (r = 0.29), respectively, and a negative correlation between conscientiousness and test anxiety (r = –0.22). The SEM demonstrated that gender was the strongest predictor of academic achievement. Lower test anxiety predicted higher GPA in girls but not in boys. Additionally, chronotype as moderator revealed a significant association between gender and GPA for evening types and intermediate types, while intermediate types showed a significant relationship between test anxiety and GPA. Our results suggest that gender is an essential predictor of academic achievement even stronger than low or absent test anxiety. Future studies are needed to explore how gender and chronotype act together in a longitudinal panel design and how chronotype is mediated by conscientiousness in the prediction of academic achievement.