Morningness-eveningness Preference Research Articles

Assortative mating in morningness–eveningness

Individuals differ in their morningness-eveningness preference (circadian preference); that is, some prefer morning hours for intellectual and physical activities and others prefer late afternoon or evening hours. This has been viewed as an interesting facet of personality. Assortative mating has been studied in personality research, but assortative mating in circadian preference has rarely been examined. Eighty-four couples participated in this study. They filled in the Composite Scale of Morningness; they also supplied data about rise times and bedtimes as well as information about relationship satisfaction and duration. The results revealed a moderate positive relationship between couple partners in morningness-eveningness which persisted after correcting for age. Similarly, correlations existed between the sleep-wake variables (rise time and bedtime) on weekdays and on the weekends, the association being higher for weekends. There was no significant correlation between length of the relationship and dissimilarity in morningness-eveningness, suggesting that the above-reported correlations reflect an initial assortment rather than convergence effects. Further, no significant correlation was found between dissimilarity in morningness-eveningness and relationship satisfaction. The results suggest that assortative mating in morningness-eveningness is likely and is probably based on an initial assortment. The likelihood to meet and mate may also be linked to chronotype. When differences in circadian preferences exist between possible partners, this reduces the likelihood that these persons meet either by accident or during work and leisure activities. Therefore, two extreme chronotypes are unlikely to meet each other because they have the smallest overlap in their preferred active time during the day due to the circadian rhythmicity.

Can you feel the rhythm? A short questionnaire to describe two dimensions of chronotype

The article presents the short questionnaire aimed at describing two dimensions of chronotype: subjective phase, i.e. morning–evening preference (M–E scale, 8 items) and subjective amplitude, i.e. distinctness of the diurnal rhythm of activation (DI scale, 6 items). The study comprised 1374 subjects (13–91 years old, 769 women, 605 men). There was no gender difference in morning–evening orientation, but women scored significantly higher on the distinctness scale ( p < .0001). Analyses were conducted in four homogenous sub-groups extracted from the investigated population: schoolchildren, university students, medical doctors, and pensioners. Younger subjects revealed significantly later subjective phase; oldest subjects showed smaller subjective amplitude. The Chronotype Questionnaire is a tool of satisfactory accuracy. It shows good enough internal reliability – significant item-total correlations in both scales and acceptable Cronbach’s alpha for M–E scale (0.66–0.84, depending on age group). DI scale showed to be weaker (Cronbach’s alpha 0.51–0.72). The questionnaire seems to be less reliable in young people at their adolescence than in older subjects. High reproducibility of the results in a two-week test–retest ( p < .001) was proved in the student group. Moreover, there was a significant correlation between self-assessments of the subjective phase investigated in a sub-group of 28 subjects in the 7-year interval.

Morningness–eveningness preferences and university entrance examination scores of high school students

This study explored whether morningness–eveningness preference influences achievement in a standardised university entrance examination. A total of 235 senior high school students aged 17–19 years responded to the Morningness–Eveningness Questionnaire (MEQ). The obtained MEQ responses indicated that out of 235 participants, 19.1% were “moderately morning” type, 68.1% were “neither” type, 11.9% were “moderately evening” type and 0.9% were “definitely evening” type (there was no “definitely morning” type student in the sample). A significant correlation was observed between MEQ scores and university entrance examination scores. In addition, morningness–eveningness preference was found to effect success in a university entrance examination. “Morning” type students performed better compared to “neither” type and “evening” type students, indicating that students with “morning” type circadian preference are at an advantage because of the starting time of the university entrance examination.

Daytime sleepiness during transition into daylight saving time in adolescents: Are owls higher at risk?

Background Individuals differ in their biological rhythms and preferences for time of day. Here, we looked at the transition into daylight saving time (DST) in adolescents. As adolescents tend to be evening types, one may expect that they suffer from a transition into DST. Methods To assess these changes, we measured daytime sleepiness and morningness–eveningness preference (CSM score) in adolescents. Results Daytime sleepiness correlated with age and CSM score. Older pupils and evening types showed a higher sleepiness. Daytime sleepiness was higher after the transition until the third week after. Older pupils and pupils scoring higher on eveningness reported higher daytime sleepiness after the transition, suggesting that these pupils suffer most from the change. Using cut-off scores for larks and owls, we found that owls showed higher sleepiness than larks. Conclusion As one consequence, class and school performance tests should not take place in the first week(s) after the transition into DST.

Executive Functions and the Ability to Sustain Vigilance During Sleep Loss

There is considerable individual variability in the ability to sustain performance during sleep loss. Preliminary evidence suggests that individuals with higher trait-like activation/functioning of the prefrontal cortex may be less vulnerable to fatigue. We tested this hypothesis in a sample of 54 healthy volunteers who were assessed bi-hourly on a variant of the Psychomotor Vigilance Test during 41 h of sleep deprivation. A subset of these subjects, representing the top and bottom 25% of the sample based on their ability to sustain vigilance performance during sleep deprivation, were compared with respect to baseline neurocognitive abilities. The sleep deprivation Resistant group (N = 13) scored significantly higher than the sleep deprivation Vulnerable (N = 13) group on all three baseline tasks assessing prefrontal executive function abilities (letter fluency, Stroop Color-Word test, Color Trails Form 2), whereas no differences were found on non-executive function tasks. Similarly, groups showed no differences on demographic variables including age, education, hand preference, morningness-eveningness preference, global intellectual ability, or pre-study sleep history. Findings are consistent with the hypothesis that greater prefrontal/executive functioning may be protective against the adverse effects of sleep deprivation and suggest that baseline executive function testing may prove useful for prediction of resilience during sleep loss.

Effects of Meal Habits and Alcohol/Cigarette Consumption on Morningness-Eveningness Preference and Sleep Habits by Japanese Female Students Aged 18–29

The relationship of meal habits and alcohol/cigarette consumption to circadian typology and sleep health in Japanese female students was studied from an epidemiological point of view. Questionnaires on Morningness-Eveningness by Torsvall and Akerstedt (1980), sleep habits, regularity of meal intake and meal amount, and style of alcohol and cigarette consumption were administered to 800 students aged 18-29 years, attending university or training schools for nutrition specialists (Aichi Prefecture, 35 degrees N). Points from ten questions were totaled to provide estimates of sleep habits given as the Unhealthy Sleep Index (UHSI). The average and standard deviation of Morningness-Eveningness scores were 16.07+/-3.53. Students who had breakfast at regular times showed significantly higher Morningness-Eveningness scores than those who ate at irregular times. Based on an integrated analysis (ANOVA) on the effect of regularity of breakfast intake on sleep health, regular breakfast intake may link to sleep health positively via the shifting to morning-type (i.e., the phase-advance of the circadian clock). However, a similar analysis promoted the hypothesis that alcohol consumption and cigarette smoking relate to sleep health negatively and directly, rather than via the shifting to evening-type (i.e., the phase-delaying of the circadian clock). In the case of young women, getting a good quality and quantity of sleep in normal life seems to be important for promoting their mental health, which may fluctuate throughout the menstruation cycle accompanied by mental symptoms as a part of premenstrual syndrome.

Gender differences in morning and evening lateness

Studies of morning–evening preference consistently recognize age differences, but gender differences are rarely reported. To examine these differences, we applied the Sleep–Wake Pattern Assessment Questionnaire (Putilov 1990, 2000, 2007). Unlike unidimensional morningness–eveningness scales, it includes separate scales for the measurement of Evening and Morning lateness (E and M, respectively). Data on 7465 adolescents and adults suggest that both E and M scores significantly decline with age. Genders are identical on the sum of E and M scores, but female respondents of any age cohort have a lower E score and a higher M score. Differences between these scores remain constant across ages. Analysis of a subset of data on 2016 adults revealed significant correlation of this difference with self-reported sleep length which, however, is not significantly longer in women. We concluded that, compared to men, women prefer earlier bedtimes and later wake up times and can desire but not obtain more sleep.

Morningness–eveningness preference and eating disorders

The aim of this work was to attempt to clarify the relationship between eveningness preferences and eating behaviour. In a survey a sample of 270 females (146 recruited in a treatment centre for eating disorders and 124 control) was administered the reduced version of the morningness–eveningness questionnaire (MEQr) and the eating disorder inventory 2 (EDI-2). A significant higher percentage of evening-type in patient versus control group was observed. About 46 patients who participated in the survey were enrolled in a further prospective study. A significant regression of symptomatology as scored by EDI-2 corresponded to a significant increase in MEQr scores (i.e. shift towards morningness). We concluded that altered eating behaviours could modulate circadian preference. The results are discussed in relation to possible applications for clinical treatment.

Correlates for poor sleepers in a Los Angeles high school

Background and purpose We explored sleep patterns including morning–evening preference and their associations with other lifestyle determinants among high school students. Particpants and methods We conducted a cross-sectional survey of students grades 9–12 from a private high school in the United States. One hundred and thirty-one students completed an online survey comprising 23 original, investigator-created questions, a mood scale, the Pittsburgh Sleep Quality Index (PSQI), and the Horne–Ostberg Morningness–Eveningness Questionnaire (MEQ). Results We found that 80% of students reported a sleep deficit. As defined by the PSQI, 69% of girls and 58% of boys in this sample were poor sleepers. Eveningness was a strong predictor of poor sleep, particularly among students aged ⩽15 years (odds ratio [OR] 9.92; 95% confidence interval [CI], 1.52–64.8), among whom poor sleep quality was also associated with a higher body mass index (BMI) (OR, 6.97; 95% CI, 1.01–48.2). Conclusions Our pilot study suggests that morningness–eveningness is a strong predictor of sleep quality among high school students.

Constant light housing during nursing causes human DSPS (delayed sleep phase syndrome) behaviour in Clock‐mutant mice

Delayed sleep phase syndrome (DSPS) is very often seen among patients with sleep-wake rhythm disorders. Humans with the 3111C allele of the human Clock gene tend to demonstrate a higher evening preference on the morningness-eveningness (ME) preference test. DSPS is thought to be an extreme form of this evening preference. Clock-mutant mice have been proposed as an animal model of evening preference. In this study, we looked at whether constant light (LL) housing of Clock-mutant mice during lactation would result in evening preference and/or DSPS. Housed under light-dark (LD) or constant dark (DD) conditions during the lactation period, both wild-type and Clock-mutant mice did not show a phase-delay in the locomotor activity measured under light-dark conditions, whereas constant light housing during lactation significantly caused a delayed onset. The magnitude of the delay during the light-dark cycle was positively associated with free-running period measured during constant darkness. Among wild, heterozygote, and homozygote pups born from heterozygous dams, only homozygote pups showed a delayed onset. Constant light-housed Clock-mutant mice exhibited a lower number and delayed peak of phospho-MAPK-immunoreactive cells in core regions of the suprachiasmatic nucleus (SCN) compared to light-dark housed wild-type or Clock-mutant mice. Activity onset returned to normal with daily melatonin injection at the lights-off time for 5 days. The present results demonstrate that Clock-mutant mice exposed to constant light during lactation can function as an animal model of DSPS and can be used to gain an understanding of the ethological aspects of DSPS as well as to find medication for its treatment.

The 3111T/C polymorphism of hClock is associated with evening preference and delayed sleep timing in a Japanese population sample

Sleep timing is influenced by the circadian system. Morningness-eveningness (ME) preference in humans is affected by the free-running period, which is determined by circadian clock-relevant genes. In this study, we investigated association between the 3111T/C polymorphism in the 3'-flanking region of hClock (Homo sapiens Clock homolog) and ME preference in 421 Japanese subjects. The Horne-Ostberg ME questionnaire (MEQ) scores showed normal distribution, with mean score of 51.2 +/- 1.4 (range, 25-73), and scores were positively correlated with sleep onset time (r = 0.541, P < 0.001) and wake time (r = 0.513, P < 0.001). MEQ scores were significantly lower in subjects with 3111C/C (n = 12) than in subjects with 3111T/C (n = 106, P < 0.001) or 3111T/T (n = 303, P < 0.001), suggesting a stronger eveningness preference in 3111C/C homozygotes. This group also showed significantly delayed sleep onset (P < 0.001), shorter sleep time (P < 0.001), and greater daytime sleepiness (P < 0.001) in comparison to parameters in the subjects with the 3111T allele. There was no significant difference in any of these parameters between the 3111C/T and 3111T/T genotypes. The influence of the 3111T/C polymorphism on ME preferences in Caucasian populations remains controversial. The present findings in a Japanese population sample, which should have a relatively low risk of population stratification effects, suggest the significance of the association of the 3111C/C allele of hClock with evening preference.

Phase relationships between sleep-wake cycle and underlying circadian rhythms in Morningness-Eveningness.

A shorter phase angle between habitual wake time and underlying circadian rhythms has been reported in evening types (E types) compared to morning-types (M types). In this study, phase angles were compared between 12 E types and 12 M types to verify if this difference was observed when the sleep schedule was relatively free from external social constraints. Subjects were selected according to their Morningness-Eveningness Questionnaire score (MEQ score). There were 6 men and 6 women in each group (ages 19-34 years), and all had a habitual sleep duration between 7 and 9 h. Sleep schedule was recorded by actigraphy and averaged over 7 days. Circadian phase was estimated by the hour of temperature minimum (T(min)) in a 26-h recording and by the timing of the onset of melatonin secretion (dim-light melatonin onset [DLMO]) measured in saliva samples. Phase angles were defined as the interval between phase markers and averaged wake time. Results showed that, in the present experimental conditions, phase angles were very similar in the 2 groups of subjects. However, results confirmed the previously reported correlation between phase and phase angle, showing that a later circadian phase was associated with a shorter phase angle. Gender comparisons showed that for a same MEQ score, women had an earlier DLMO and a longer phase angle between DLMO and wake time. Despite a significant difference in the averaged circadian phases between E-type and M-type groups, there was an overlap in the circadian phases of the subjects of the 2 groups. Further comparisons were made between the 2 circadian types, separately for the subgroups with overlapping or nonoverlapping circadian phases. In both subgroups, the significant difference between MEQ scores, bedtimes, and wake times were maintained in the expected direction. In the subgroup with nonoverlapping circadian phases, phase angles were shorter in E-type subjects, in accordance with previous studies. However, in the overlapping subgroup, phase angles were significantly longer in E types compared to M types. Results suggest that the morningness-eveningness preference identified by the MEQ score refers to 2 distinct mechanisms, 1 associated with a difference in circadian period and phase of entrainment and the other associated with chronobiological aspects of sleep regulation.

Relationship between watching late night TV and morningness-eveningness of 18-22-year old Japanese students

Late night TV programs are currently common among several Japanese broadcasting corporations, and some stations continuously broadcast 24 h a day. An epidemiological study was conducted on the effects of watching late night TV on morningness-eveningness preference and sleep habits of Japanese students aged 18–22 years attending university, a physical therapist or a nurse training school. Students who watched late night TV were more evening-typed (Mann-Whitney U-test, P = 0.011) and went to bed later (Chi-squared test, P < 0.001) than those who did not. There was a significant negative correlation between the frequency with which students watched late night TV and morningness after a Morningness-Eveningness questionnaire was conducted (Kruskal-Wallis test, P < 0.001).

Morningness-eveningness preference, and mental and physical symptoms during the menstrual cycle of Japanese junior high school students

Morningness-eveningness (M-E) preference and whether it was related to varying mental and physical conditions during the menstrual cycle of female students attending a Japanese junior high school, located in the suburban region in Nangoku city (33.3 N), Kochi prefecture, was studied. Those students who were beyond their first year after menarche were more evening-typed than those who were in their first year of menarche or those who had not yet begun their menstrual function. The M-E preference has no significant correlation with mood, periodical stability of the menstrual cycle or menstrual pain. The bedtime of those students who had an irregular menstrual cycle was significantly later than that of the students who had a stable cycle.

Further Results on the Association between Morningness-Eveningness Preference and the Season of Birth in Human Adults

Morningness-eveningness preference by the self-rated Morningness-Eveningness Questionnaire (MEQ) has earlier been shown to be associated with the subjects’ season of birth. Here, we obtain this result for a new sample of 2,125 university students and for the sample obtained by pooling the data with the earlier study, yielding totally 3,709 Italian and Spanish subjects. An nonlinear regression of MEQ as a cosine curve according to the month of birth, adjusting for age and gender, gave a maximum (morningness) around the transition between the birth months December and January, and a minimum (eveningness) around the transition between the birth months June and July. Multiple logistic regressions showed that for females as well as for males, the group born during the half-year April to September containing summer had a significantly lower proportion of morning types as compared with the group born during the half-year October to March containing winter. This was more pronounced for males. Moreover, a significantly higher proportion of morning types among females compared with males was found only in the group born during April to September, but not in the group born during October to March. There was a weak but statistically significant positive correlation between MEQ and age in the sample’s limited age range of 17–30 years. We discuss the results in terms of the mutually inhibitory systems of melatonin and dopamine, and find further support for a hypothesis that it is the variation in the length of photoperiod during the gestational or perinatal period that contributes significantly to the season of birth variation found in the morningness-eveningness preference among adults.

Gender and Circadian Typology

The aim of the present study was to analyse gender difference in morningnesseveningness preference by using the open questions of the Morningness-Eveningness Questionnaire. A sample of 1319 university students, age range 18 to 30 years, was administered the MEQ. A total of 240 (18.19%) morning-types, 795 (60.27%) intermediate-types, and 284 (21.53%) evening-types were identified. The men and women differed significantly in their mean scores (p < 0.00001) and distribution per circadian typology (p < 0.005), with the men presenting a more pronounced eveningness preference. The MEQ items referring to sleep onset phase were sensitive to gender differences irrespective of circadian typology. In contrast, the MEQ item regarding waking up time showed a significant crossover between gender and circadian typology, i.e., evening-men preferred waking up later than evening-women, but morning-men had a propensity to wake up earlier than morning-women. The results seem to support the hypothesis that the circadian system is more flexible in men than in women.

Morningness-eveningness preference and mood in Japanese junior high school students.

The relationship between morningness-eveningness (M-E) preference and mood in Japanese students aged 12-15 years (690 boys and 649 girls) was investigated. No significant difference in M-E preference was seen between genders. Girls became gloomy more frequently than boys, whereby the girls who experienced melancholy more frequently tended to prefer evening. The correlation between mood and M-E preference, which was demonstrated only by girls, might be linked to a rapid shift to evening preference by girls in the past couple of years.

Effect of daytime light conditions on sleep habits and morningness-eveningness preference of Japanese students aged 12-15 years.

The effect of daytime light conditions on the sleep habits and morning-evening preference of Japanese junior high school students (415 girls and 411 boys; age range, 12-15 years old) was studied. Students who were outdoors during the short break between classes or their lunch-time break were more morning-type people than those who remained indoors. Students who shut out the light from outside showed longer subjective sleep latency and appealed more shallow sleep rather than those who did not. Sunlight can be an important factor for the timing of sleep based on the circadian system of Japanese young students.

Morningness-eveningness dimension: is it really a continuum?

Abstract Several self-evaluation instruments have been developed for identifying the individual circadian typology. The use of these instruments suggests the idea that the morningness-eveningness dimension could be considered as a continuum between two extremes. Aim of the present work is to support such an idea by means of external criteria. A sample of 222 subjects was administered the Morningness-Eveningness Questionnaire (MEQ). Six typologies were considered: definitely morning, moderately morning, intermediate-morning, intermediate-evening, moderately evening, and definitely evening. Body temperature, and subjective alertness readings were collected at 08:00, 14:00, and 23:00 in counterbalanced order. As regards subjective alertness a significant interaction (ANOVA) between circadian typology and time of day was found. At 08:00 the recorded values of subjective alertness gradually increased starting from the definitely evening extreme typology to the definitely morning one, vice-versa at 23:00. These results seem to support the idea that the morningness-eveningness dimension could be considered as a continuum between two extremes: morning-evening preference. Nevertheless, this is especially true for subjective alertness. Suggestions about how to use the MEQ are put forward.

GENDER DIFFERENCES IN MORNINGNESS–EVENINGNESS PREFERENCE

Morningness–eveningness preference (morning-, intermediate-, evening-type) or circadian typology is the individual difference that most clearly explains the variations in the rhythmic expression of biological or behavioral patterns. The aim of this study was to analyze gender difference in morningness–eveningness preference using the Horne and Östberg questionnaire in the largest university student population selected so far (N=2135), with an age range 18–30 yr. Morningness–eveningness questionnaire (MEQ) score distribution closely correlated to the normal curve (range=17–78, mean=48.25; SD=10.11), with 338 (15.84%) morning-types, 1273 (59.62%) intermediate-types, and 524 (24.54%) evening-types. The men and women differed significantly in their mean scores (p<0.0001) and distribution per circadian typology (p<0.00001), with the men presenting a more pronounced eveningness preference. Three factors were identified by factor analysis: time of greatest efficiency (I), sleep time/sleep phase (II), awakening time/sleep inertia (III). The MEQ items sensitive to gender differences were essentially those included in factor I and factor II. The results are discussed in relation to recent models of circadian regulation of the sleep–wake cycle.