Morningness Eveningness Research Articles

What is the relationship between obesity and new circadian rhythm parameters in Turkish children and adolescents? A case-control study.

Although the relationship between circadian rhythm parameters and obesity in children and adolescents is recognized, there are few studies on this topic. The concept of sleep-corrected social jetlag (SJLsc) has been formulated recently, but its relationship with childhood obesity has not yet been established. Therefore, we thought that SJL might play an important role in the etiology of obesity. Accordingly, we aimed to compare circadian rhythm parameters between obese and normal-weight children and adolescents. Seventy-nine obese and eighty-two normal-weight children and adolescents aged between 8 and 17 years participated in this case-control study, which took place in the Mardin province of Turkey. Data were collected with a sociodemographic information form, the Childhood Chronotype Questionnaire, and anthropometric measurements. The average ages of the obese participants and controls were 12.3±2.3 and 12.4±2.2 years, respectively. Obese young people had greater evening preference, longer sleep debt duration, SJL duration and SJLsc duration, and higher Morningness-Eveningness Scale (MeScale) scores; and shorter mean sleep duration (p<0.005). In regression analyses, BMI z scores were significantly correlated with all circadian rhythm parameters, except SJLsc duration, while WC z scores were significantly correlated with all circadian rhythm parameters, except mean sleep duration. After adjustment, the high MeScale scores (OR: 1.142, p<0.05) and the presence of psychiatric disorder in the mother (OR: 15.075, p<0.05) were associated with obesity. Circadian rhythm parameters can play an important role in the etiology of obesity. Future studies with larger samples and fewer confounding factors are needed to clarify the etiological factors.

Prevalence of Circadian Rhythm Sleep-Wake Disorder in Outpatients with Schizophrenia and Its Association with Psychopathological Characteristics and Psychosocial Functioning.

The prevalence of circadian rhythm sleep-wake disorder (CRSWD) among patients with schizophrenia is not clear. The effect of comorbid CRSWD on such patients has also not been fully evaluated yet. Outpatients with schizophrenia in the maintenance phase who visited Tokyo Women’s Medical University Hospital between April 2018 and March 2019 participated in this study. The Brief Psychiatric Rating Scale (BPRS), the Clinical Global Impressions–Severity Illness Scale (CGI-S), Global Assessment of Functioning (GAF), World Health Organization Disability Assessment Schedule II, Insomnia Severity Index (ISI), and Morningness–Eveningness Questionnaire (MEQ) were administered, and the patient responses with and without CRSWD were compared. Of the 105 patients with schizophrenia, 19 (18.1%) had CRSWD. There were trends toward higher BPRS and lower GAF scores in the CRSWD group than in the non-CRSWD group, although these did not reach statistical significance following a false discovery rate correction. Among the BPRS subitems, the anxiety scores were significantly higher in the CRSWD group than in the non-CRSWD group (p < 0.01). CRSWD was highly prevalent among patients with schizophrenia in the maintenance phase. Comorbidities of CRSWD may affect psychopathological characteristics and psychosocial functioning.

Role of Living Conditions and Socioenvironmental Factors on Chronotype in Adolescents

An individual’s chronotype, defined as the preference for rest and activity at different times of the day, is linked to several physiological and psychological outcomes. Research on environmental determinants of chronotype has focussed mostly on geographic location, whereas other socioenvironmental determinants have been neglected. We aimed to investigate the association between other previously unrecognized socioenvironmental factors and chronotypes in adolescents. We analysed data of 1916 Bengali adolescents (aged between 13–14 years, 47% girls). Chronotype was determined by the reduced morningness–eveningness questionnaire (rMEQ), and socioenvironmental factors were identified through a structured questionnaire. Associations were analysed using multinomial logistic regression models. Our findings demonstrated that living in urban areas, the presence of a smoker at home, and higher parental education were associated with a higher evening activity (eveningness), while the use of biomass cooking media (compared to liquefied petroleum gas) and assisting parents in farming were associated with higher morningness in adolescents. This is the first study to identify the association between previously unrecognized socioenvironmental factors and chronotypes delineating the interaction between environment and sleep in adolescents and might help the parents to understand the importance of a proper sleep-activity rhythm of their kids through a comprehensive understanding of their surrounding environment and other factors.

Greatest changes in objective sleep architecture during COVID-19 lockdown in night owls with increased REM sleep.

Study ObjectivesThe COVID-19 pandemic has had dramatic effects on society and people’s daily habits. In this observational study, we recorded objective data on sleep macro- and microarchitecture repeatedly over several nights before and during the COVID-19 government-imposed lockdown. The main objective was to evaluate changes in patterns of sleep duration and architecture during home confinement using the pre-confinement period as a control.MethodsParticipants were regular users of a sleep-monitoring headband that records, stores, and automatically analyzes physiological data in real time, equivalent to polysomnography. We measured sleep onset duration, total sleep time, duration of sleep stages (N2, N3, and rapid eye movement [REM]), and sleep continuity. Via the user’s smartphone application, participants filled in questionnaires on how lockdown changed working hours, eating behavior, and daily life at home. They also filled in the Insomnia Severity Index, reduced Morningness–Eveningness Questionnaire, and Hospital Anxiety and Depression Scale questionnaires, allowing us to create selected subgroups.ResultsThe 599 participants were mainly men (71%) of median age 47 (interquartile range: 36–59). Compared to before lockdown, during lockdown individuals slept more overall (mean +3·83 min; SD: ±1.3), had less deep sleep (N3), more light sleep (N2), and longer REM sleep (mean +3·74 min; SD: ±0.8). They exhibited less weekend-specific changes, suggesting less sleep restriction during the week. Changes were most pronounced in individuals reporting eveningness preferences, suggesting relative sleep deprivation in this population and exacerbated sensitivity to societal changes.ConclusionThis unique dataset should help us understand the effects of lockdown on sleep architecture and on our health.

Biological Rhythm and Chronotype: New Perspectives in Health.

The circadian rhythm plays a fundamental role in regulating biological functions, including sleep–wake preference, body temperature, hormonal secretion, food intake, and cognitive and physical performance. Alterations in circadian rhythm can lead to chronic disease and impaired sleep. The circadian rhythmicity in human beings is represented by a complex phenotype. Indeed, over a 24-h period, a person’s preferred time to be more active or to sleep can be expressed in the concept of morningness–eveningness. Three chronotypes are distinguished: Morning, Neither, and Evening-types. Interindividual differences in chronotypes need to be considered to reduce the negative effects of circadian disruptions on health. In the present review, we examine the bi-directional influences of the rest–activity circadian rhythm and sleep–wake cycle in chronic pathologies and disorders. We analyze the concept and the main characteristics of the three chronotypes.

Evening chronotype is associated with poor work ability and disability pensions at midlife: a Northern Finland Birth Cohort 1966 Study

ObjectivesThis is the first general population study to evaluate whether evening chronotypes (E) have poorer work ability (WA) and higher probability for early disability pensions (DPs) than morning types (M)...

Sleep and chronotype in relation to work-related stress and negative affect: The moderating role of a flexible start of work

Abstract Objectives The present study investigated the relationships between sleep (sleep duration and need for additional sleep time in the morning), chronotype, work-related stress, and negative affect in daytime workers. Furthermore, it was examined whether a flexible start of work moderates these relationships. Methods A cross-sectional online study was conducted. Participants were 438 (247 female) daytime workers between 18 and 73 years (mean = 37.68, standard deviation = 12.39). The questionnaire included the “sleep duration” subscale of the Pittsburgh Sleep Quality Index (PSQI), the Morningness–Eveningness Questionnaire (MEQ), two subscales of the Trier Inventory for the Assessment of Chronic Stress (TICS), the negative affect scale of the Positive and Negative Affect Schedule (PANAS), questions regarding how many minutes participants would like to sleep longer in the morning, and how flexible their start of work is. Results Short sleep duration and a greater need for additional sleep in the morning were significantly associated with late chronotype. Shorter sleep duration, a greater need for additional sleep, and a late chronotype were associated with higher work-related stress and negative affect. A flexible start of work moderated these relationships: People with longer sleep duration, less need for additional sleep time, and an early chronotype showed lower stress and negative affect levels when having a flexible start of work. A flexible start of work showed no or negative effects on workers with shorter sleep duration, a greater need for additional sleep time, or a late chronotype. Conclusions The effect of a flexible start of work for daytime worker’s well-being depends on a person’s individual sleep timing and chronotype.

Prevalence of Sleep Practices, Circadian Types and Their Effect on Sleep Beliefs in General Population: Knowledge and Beliefs About Sleep and Sleep Practices (KNOBS Survey)

We spend one-third of our lifetime in sleep. There is paucity of data on sleep duration, practices, circadian types and their influence on sleep beliefs in general population. This study was done to evaluate the knowledge and beliefs about sleep hygiene, sleep practices and to compare these practices among different gender and age groups of Indian population. The influence of circadian typology on the sleep beliefs was also studied. An online survey to capture data on demographics, sleep hygiene practices, reduced morningness–eveningness scale and the sleep beliefs scale (SBS) was created. Survey was completed by 832 adult respondents, with a mean age of 34.70 ± 13.11 years. Majority were female (53.96%) and most respondents (88.4%) lived in urban areas. Mean sleep duration was 7.36 ± 0.25 h. Sleep duration was longer in weekends than weekdays. More than 80% spent time with electronic devices, on social media prior to bedtime. Exercising, alcohol use and viewing television prior to bedtime was reported in a higher percentage of males. Morning types was the most prevalent circadian type (47.5%) followed by the neither type. Morning types (13.09 ± 3.4) had significantly better sleep beliefs than the neither types (12.5 ± 3.5) and evening types (11.9 ± 3.1) with a p value of 0.007. The mean sleep duration in our respondents is 7.36 ± 0.25 h. Majority admitted to screen-time before sleep. The younger respondents had higher prevalence of evening types and worse sleep beliefs. Gender played an insignificant role in circadian typology.

Reliability and Validity of the Turkish Version of the Morningness – Eveningness Questionnaire

Background: People are divided into different chronotypes in relation to their circadian rhythm features. The Morningness–Eveningness Questionnaire (MEQ), developed by Horne and Östberg, was the first and is the most used questionnaire for determining the chronotype of people. The reliability and validity of MEQ were tested in this study due to some deficiencies and inconsistencies in previous reliability and validity studies for the Turkish versions of MEQ and deficiencies regarding the validity and reliability of other versions of MEQ. Subjects and Methods: MEQ was translated into Turkish based on the opinions of five academics who were experts in their respective fields and the suitability and content validity of the questionnaire were ensured. The Turkish MEQ was administered to 419 undergraduate students aged 18–34 years. Robust minimum rank factor analysis (MRFA) was used to reveal the construct validity of the questionnaire. Results: As a result of the analyses, the questionnaire was examined in three factors. None of the items were excluded from the study and all items were collected under three factors. The explained total variance value was 42.7%, and the factors explained 64% of common (shared) variance in MRFA. According to the reliability analysis, Cronbach's alpha value for the MEQ Turkish version was satisfactory for the overall questionnaire (0.765). Conclusions: The MEQ version developed in this study is more valid and reliable compared with other versions. However, these results support that a more detailed instrument for morningness and eveningness can be developed.

Factor structure and psychometric properties of the Persian versions of the Pediatric Daytime Sleepiness Scale and Morningness-Eveningness Scale for Children.

BACKGROUND:The Pediatric Daytime Sleepiness Scale (PDSS) and the Morningness–Eveningness Scale for Children (MESC) are widely used to measure two important facets of sleep patterns, but neither have been adapted and validated for use in Iran. The purpose of this study was to examine the psychometric properties and factor structure of the Persian versions of the PDSS and the MESC in a sample of Iranian adolescents.MATERIALS AND METHODS:The Persian versions of PDSS and MESC were translated and administered to a representative sample (n = 407) of Iranian early adolescents, aged 9–15 years, who attended school in morning shifts. The factor structure of both scales, found in prior studies, was tested using Confirmatory Factor Analyses to assess their validity and reliability.RESULTS:The results revealed that the model fit indices of the one factor solution of the PDSS and the two factor solution of the MESC were acceptable to good. A high Pearson correlation was found between raw and latent factor scores for the PDSS and the two factors derived from the MESC (i.e., Morningness and Planning). Furthermore, the higher the PDSS score (more daytime sleepiness), the lower the MESC scores (more eveningness), indicating criterion validity of the scales showing the expected increase in daytime sleepiness in evening oriented adolescents who wake up early for attending school.CONCLUSION:The Persian versions of the PDSS and the MESC can be considered reliable and valid tools for evaluating, respectively, daytime sleepiness and morningness-eveningness in the adolescent population of Iran.

Impact of Social Jetlag and Circadian Patterns on Patients with Metabolic and Nocturnal Eating Syndromes

Objective Metabolic syndrome (MS) can result in many health hazards, including coronary heart disease, diabetes, fatty liver, and several types of cancer. Social jetlag is a discrepancy between biological and social timing. Circadian rhythm disruption is suggested to disturb the hypothalamus pituitary adrenal (HPA) axis. Disturbance of the HPA axis was reported to increase the risk of developing visceral obesity and MS. We hypothesized that social and circadian rhythm disruptions negatively impact patients with obesity and MS. This study aimed to detect the associations between obesity, MS, nocturnal eating syndrome, and social jetlag. Methods One hundred obese patients were recruited (61 had MS). The patient group was compared to a healthy nonobese control group (n=50). Each studied patient was subjected to three question-naires [Morningness Eveningness Questionnaire, Night Eating Questionnaire (NEQ), and Sleep Timing Questionnaire]; their anthropometric measures were taken, fasting lipid profile, liver, and kidney function tests, and fasting insulin were also assessed. Results Patients with evening chronotype were mainly from the obese with MS group. NEQ total score was higher in obese patients with MS, and it showed a significant positive correlation with BMI. Total cholesterol, NEQ score, age, sleep latency, and awakening after sleep onset had significant associations with MS. Conclusion Evening chronotype has a significant association with MS. Social jetlag negatively impacts obesity and MS, leading patients to have frequent nocturnal eating behaviors. Screening for sleep profile and social jetlag should be included in routine clinical practice of managing obesity. Key Words: Key WordsMetabolic syndrome; Obesity; Social jetlag; Chronotype, Night eating syndrome

Time of Day Matters: An Exploratory Assessment of Chronotype in a Forensic Psychiatric Hospital.

A growing body of evidence links the late chronotype to mental illness, aggression, and aversive personality traits. However, much of what we know about these associations is based on healthy cohorts, and it is unclear how individuals with high levels of aggression, including forensic psychiatric populations, but not offenders, are affected. The present study aimed to measure chronotype in a forensic psychiatric inpatient population, evaluate the impact of diagnosis, and identify any interactive relationships between chronotype, diagnosis, aggression, and dark triad traits. Subjects completed the reduced Morningness–Eveningness Questionnaire (rMEQ), Munich ChronoType Questionnaire (MCTQ), Pittsburgh Sleep Quality Index (PSQI), Buss Perry Aggression Questionnaire–Short Form (BPAQ-SF), and Short Dark Triad Questionnaire (SD3). We sampled 55 forensic psychiatric patients (52 males) between the ages of 23 and 73 years (mean ± SD: 39.6 ± 14.3 years). Among the patients sampled, 25% were evening types and 36% were morning types. Eveningness was greater in patients with a personality disorder; however, no chronotype differences were found for psychosis patients. Patients without psychosis had a positive association between anger and eveningness, as well as between hostility and eveningness. For subjects with a substance use disorder, morningness was positively associated with narcissism. Conversely, an association between eveningness and greater narcissism was identified in patients who did not have a substance use disorder. These findings suggest that, compared to the general population, evening types are more prevalent in forensic psychiatric populations, with the strongest preference among patients diagnosed with a personality disorder. No differences in chronotype were identified for psychosis patients, which may be related to anti-psychotic medication dosing. Given the sex distribution of the sample, these findings may be more relevant to male populations.

The Frequency of Pregnancy Associated Sleep Disorders Among Pregnant Mothers Who Referred to Rasoul-Akram Hospital for Prenatal Care 2018 - 2019

Background: Sleep, a physiological need, may be disturbed during pregnancy due to the psychological, anatomical, biochemical, hormonal, and emotional adaptations. Objectives: The present study aimed to investigate the frequency of morningness/eveningness, insomnia, and sleep disorders in pregnant mothers. Methods: All healthy pregnant women who referred to Rasoul-Akram Hospital in 2018-2019 for prenatal care without severe medical diseases were included in the study by census method. They were asked to fill their demographics, Morningness Eveningness questionnaire (MEQ), Pittsburgh sleep quality index (PSQI), and insomnia severity index (ISI) after signing their informed consent. The data were analyzed using SPSS V.21. Women who gave birth before the third trimester were excluded from analysis. Results: A total of 347 women completed the study; mean age: 31.46 ± 5.36 years, mean gestational age: 24.68 ± 9.62 weeks. The mean MEQ score was 48.77 ± 5.15; 8.1% were moderate evening type, 85.3% intermediate, and 2.6% moderate morning type. Mean ISI score was 16.92 ± 5.51; 91.9% had insomnia; 31.1% reported (rather or very) poor sleep quality. The frequency of insomnia (based on ISI scores) and sleep disorders (based on PSQI dimensions) were neither different among the three trimesters of pregnancy, nor between complicated and uncomplicated pregnancies (P &gt; 0.05). The MEQ score (P = 0.008, OR = 4.275) was positively, and the academic degree was negatively (P = 0.005, OR = 0.202) associated with sleep disorder. Conclusions: The majority of pregnant mothers reported insomnia, and about one-third reported poor sleep quality, indicating the necessity of paying greater attention to the sleep disorders of pregnant women from the early trimester to prevent further complications.

Influence of circadian rhythm on individual differences in morningness-eveningness scale among normal healthy subjects

The circadian rhythm is a biological rhythm that produces physical, psychological and behavioural changes in a living organism, and it follows a daily cycle. This cycle depends on the response of the organism to light and darkness in the environment. The aim of the study was to analyse and evaluate the influence of circadian rhythm on individual differences in morningness-eveningness attitude among the normal healthy subjects. Morningness eveningness questionnaire is a standard tool to assess sleep, wakefulness alertness, self-awareness and best time activity of the individual either in the morning time or evening time. This questionnaire was self-administered, and it consisted of 10 questions and was circulated via google forms. The results revealed that a majority of 85% of the participants are evening types of persons and the significance level was a p-value &amp;lt; 0.05 of the chi-square test. The present study assessed the influence of the circadian rhythm on the morningness-eveningness scale, and results revealed that most of the participants were alarm dependant, had difficulty in waking up. They were very active in the evening and went to bed very late. So, the study concluded that the majority of participants were evening type of person.

Individual Circadian Preference, Shift Work, and Risk of Medication Errors: A Cross-Sectional Web Survey among Italian Midwives

Background: In order to explore the possible association between chronotype and risk of medication errors and chronotype in Italian midwives, we conducted a web-based survey. The questionnaire comprised three main components: (1) demographic information, previous working experience, actual working schedule; (2) individual chronotype, either calculated by Morningness–Eveningness Questionnaire (MEQ); (3) self-perception of risk of medication error. Results: Midwives (n = 401) responded “yes, at least once” to the question dealing with self-perception of risk of medication error in 48.1% of cases. Cluster analysis showed that perception of risk of medication errors was associated with class of age 31–35 years, shift work schedule, working experience 6–10 years, and Intermediate-type MEQ score. Conclusions: Perception of the risk of medication errors is present in near one out of two midwives in Italy. In particular, younger midwives with lower working experience, engaged in shift work, and belonging to an Intermediate chronotype, seem to be at higher risk of potential medication error. Since early morning hours seem to represent highest risk frame for female healthcare workers, shift work is not always aligned with individual circadian preference. Assessment of chronotype could represent a method to identify healthcare personnel at higher risk of circadian disruption.

Work Shift and Circadian Rhythm as Risk Factors for Poor Sleep Quality in Public Workers from Murcia (Spain).

The purpose of this study was to determine the prevalence of sleep quality and to investigate variables predicting the risk of poor sleep quality in public workers from Murcia (Spain). A cross-sectional and prospective study was conducted from October 2013 to February 2016 in 476 public workers. The Pittsburgh Sleep Quality Index was used to measure the quality of sleep, and the reduced scale of the Horne and Österberg Morningness–Eveningness Questionnaire was applied to analyze the circadian typology. The predictive variables of self-reported poor sleep quality were identified by multivariate logistic regression. No significant differences were found according to sex in the overall sleep quality scores (5 ± 2.9 versus 5.1 ± 3, p = 0.650), but there were in the duration of sleep. Three percent of females slept <5 hours compared to 2% of men (p = 0.034). Fixed morning shifts (OR = 1.9, 95% CI 1.3–3.1; p = 0.007) and evening chronotypes (OR = 1.6, 95% CI 1.0–2.3; p = 0.017) were independent predictors of suffering from poor sleep quality. In conclusion, the frequency of self-reported poor sleep quality among public workers from Murcia was 37.4%. Being a public worker with a fixed morning shift and having an evening chronotype demonstrated to be associated with the quality of sleep.

Validation of the Portuguese Variant of the Munich Chronotype Questionnaire (MCTQPT).

IntroductionDifferences in the manner circadian clocks entrain to the 24-h day are expressions of different chronotypes that can range from extreme early to extreme late, from proverbial larks to owls. The Morningness Eveningness Questionnaire (MEQ) was one of the first to assess daily preference based on subjective self-assessment – a psychological construct. The later developed Munich Chronotype Questionnaire (MCTQ) uses instead the actual sleep timing to assess chronotype. It calculates the mid-sleep point, halfway between onset and offset on work-free days (MSF), which is then corrected for potential oversleep on free days compensating for sleep debt accumulated over the workweek (MSFsc). MSFsc is expressed in local time and is thought to be a proxy for “phase of entrainment” of the circadian clock. The MCTQ-derived chronotype is therefore a biological construct. In the present report, we validate the Portuguese variant (MCTQPT) of the MCTQ. Portugal is of particular interest, since it is thought to consist of especially late chronotypes.MethodsWe have used three methods to assess the timing of daily behavior, namely, the chronotype (MCTQ), the daily preference (rMEQ), and a simple self-assessment (time-of-day type). A total of 80 healthy adults living in Portugal, with age and sex distributed according to the Portuguese population, were recruited. We analyzed 4 weeks of continuous records of actimetry data to validate the MCTQPT and used the rMEQ to compare between a biological chronotype (sleep timing) and a psychological chronotype (daily preference). MCTQ variables were analyzed by descriptive statistics; correspondence between measurements was done by Spearman correlations or cross-tabulation; in a subset of 41 individuals, test–retest reliability was assessed.ResultsMCTQ-derived variables (MSF, MSW, MSFsc) correlated highly with their counterparts calculated from actimetry (MSW: rho = 0.697; MSF: rho = 0.747; MSFsc: rho = 0.646; all p < 0.001). The MCTQ assessment of the chronotype showed good test–retest reliability (rho = 0.905; p < 0.001). The rMEQ score correlates with MSFsc (rho = −0.695; p < 0.001), and the agreement for the self-assessment with the MSFsc was fair (kw = 0.386; p < 0.001).ConclusionThe Portuguese variant of the MCTQ revealed to be a reliable questionnaire to assess the chronotype for the Portuguese adult population, as previously reported for other countries.

Chronotype distribution in the Chinese population

Purpose: Individual chronotypes are reported to be closely associated with mood, health status, and even disease progression. However, no reports of chronotype distribution in the Chinese population have been made available to date. Methods: We performed a chronotype survey using the classic Morningness–Eveningness Questionnaire both online and offline. The webpage-based online survey was distributed via a social network application on mobile phones. The offline survey was distributed to local primary and middle schools. A total of 9476 questionnaires were collected, of which 8395 were valid. The mean age of the participants was 30.38 ± 11.47 years, and 37.38% were male. Results: Overall, the Chinese chronotypes showed a near-normal distribution with a slight shift toward eveningness. When analyzed in different age groups, the overall Chinese population was shown to be “latest” in their early twenties. In the young population, two significant points of change in chronotype were identified at the ages of 10 and 16 years. The chronotype composition remained relatively stable during early adulthood (from 17 to 28 years of age). Conclusion: This study generated the first overview of chronotype distribution in the Chinese population and will serve as essential background data for future studies.

0336 The Relationship Between Chronotype, Sleep and Sport Motivation in Adolescents

Abstract Introduction Studies have shown that sleep affects physical performance and certain aspects of motivation in general. Even though it is well known that adolescents are generally sleep deprived, very few studies have investigated the impact of sleep on the inactivity of teens. The aim of this study was to determine the association between sleep and sport motivation in teenagers. Methods 176 young, physically active participants (10-18y; 86 male) completed an online survey comprised of questions extracted from the Adolescents Sleep Habits Survey, the Pediatric Daytime Sleepiness Scale, the Morningness Eveningness Questionnaire, and the Sports Motivation Scale-28. The self-determination theory of motivation was used to determine the different types of motivation, from the most autonomous motivation (intrinsic motivation) to the least autonomous (extrinsic motivation-externally regulated). Amotivation represent an absence of motivation. Pearson correlations were computed between the sleep variables (sleep habits, daytime sleepiness, chronotype score) and the motivation variables (different types of motivation, and amotivation scores). Results Results show that amotivation is significantly associated with daytime sleepiness (r=.16, p =.03). The external regulated form of extrinsic motivation score is significantly associated with daytime sleepiness (r=.157, p=.037), chronotype score (r=-.164, p=.03), and bedtimes on weekends (r=.156, p=.042). The intrinsic motivation score is significantly associated with wake times on weekdays (r=-189, p=.012). Conclusion These results suggest that eveningness, higher daytime sleepiness, and later bedtimes on weekends are associated with amotivation and external regulation of sport motivation. Research has shown that teens who present those two characteristics are more likely to drop out of sports teams or leagues. This could have important implications when addressing inactivity and sport motivation problems in adolescents. Support N/A

Impact of Meal Timing and Chronotype on Food Reward and Appetite Control in Young Adults.

Early meal timing and chronotype are associated with lower BMI, but their impact on appetite is poorly understood. We examined the impact of meal timing and chronotype on appetite and food reward. Forty-four adults were divided into early (EC; Morningness–Eveningness Questionnaire (MEQ) score = 55 ± 5) or late chronotype (LC; MEQ score = 40 ± 6) and assessed for body mass index, habitual energy intake (EI; three-day online dietary record) and eating behavior traits from the Three-Factor Eating Questionnaire (TFEQ). Participants attended the laboratory after ≥3 h fast on two occasions for early (AM; 8–10 a.m.) and late (PM; 4–6 p.m.) counterbalanced testing sessions in a 2 × 2 design. Appetite ratings and food reward (validated diurnal Leeds Food Preference Questionnaire) were measured in response to a standardized test meal. LC was associated with higher BMI (p = 0.01), but not with EI or TFEQ. The composite appetite score was lower in AM than PM (MΔ= −5 (95% CI −10, −0.2) mm, p = 0.040). Perceived test meal fillingness was higher in AM than PM and EC compared to LC (p ≤ 0.038). Liking and wanting high-fat food were lower in AM than PM (p ≤ 0.004). The late chronotype was associated with greater desire for high-fat food (p = 0.006). To conclude, early meal timing and early chronotype are independently associated with smaller appetite and lower desire for high-fat food.