Psychometric properties of the Turkish reduced morningness and eveningness questionnaire.

The aim of this study was to examine the psychometric properties of the 5-item Turkish Reduced Morningness-Eveningness Questionnaire (rMEQ) for the first time. The study involved 875 university students in an adaptation and validation study. Participants completed the rMEQ, MEQ, Depression Anxiety Stress Scale-21 (DASS-21), Insomnia Severity Index (ISI), Barratt Impulsiveness Scale Short Form (BIS-SF), and Oxford Happiness Questionnaire Short Form (OHQ-SF). The factor structure, convergent validity, internal consistency, sensitivity, and specificity of the rMEQ were examined. The confirmatory factor analysis showed that the rMEQ had a one-dimensional structure with good fit indices (χ2/df = 2.94, CFI = 0.990, TLI = 0.979, RMSEA = 0.047, and SRMR = 0.019). There was a significantly strong correlation between rMEQ and MEQ. In addition, we found a significantly weak correlation between rMEQ and DASS-21, ISI, BIS-SF, and OHQ-SF. The internal consistency coefficients of rMEQ were Cronbach's α = 0.706 and McDonald's ω = 0.740. The sensitivity and specificity of rMEQ were 83.3%-92.7% for morning types and 86.3%-87.3% for evening types. The Turkish rMEQ has adequate psychometric properties and can be used to assess an individual's chronotype.

The Japanese version of the reduced morningness-eveningness questionnaire.

Circadian typology, or "morningness" and "eveningness," is generally assessed using the Morningness-Eveningness Questionnaire (MEQ), a 19-item scale that could be burdensome in large-scale surveys. To overcome this, a 5-item version known as the reduced morningness-eveningness questionnaire (rMEQ), which is sensitive to the assessment of circadian typology, was developed; however, a validated Japanese version of the rMEQ is yet to be established. This study aimed to develop and validate the Japanese version of the rMEQ. Five essential items for the rMEQ were selected from existing Japanese MEQ data (N = 2,213), and the rMEQ was compiled. We conducted a confirmatory factor analysis for the psychometric properties of the rMEQ and confirmed its robust one-factor structure for evaluating morningness-eveningness (GFI = 0.984, AGFI = 0.951, CFI = 0.935, and RMSEA = 0.091). Reliability was evaluated via internal consistency of rMEQ items using Cronbach's α and McDonald's ω, and the values were 0.618 and 0.654, respectively. The rMEQ scores strongly correlated with MEQ (ρ = 0.883, p < 0.001), and classification agreement (Morning, Neither, and Evening types) between rMEQ and MEQ was 77.6% (Cramer's V = 0.643, Weighted Cohen's κ = 0.72), confirming the validity. The Japanese rMEQ may be a valuable tool for the efficient assessment of circadian typologies.

Effects of cognitive behavioural therapy and bright light therapy for insomnia in youths with eveningness: study protocol for a randomised controlled trial.

BACKGROUND: Insomnia and eveningness are common and often comorbid conditions in youths. While cognitive behavioural therapy for insomnia (CBT-I) has been suggested as a promising intervention, it remains unclear whether it is sufficient to also address circadian issues in youths. In addition, despite that light has been shown to be effective in phase-shifting one's circadian rhythm, there has been limited data on the effects of bright light therapy and its combination with CBT-I on sleep and circadian outcomes in youths. The current protocol outlines a randomised controlled trial that examines the efficacy of CBT-I and CBT-I plus bright light therapy (BLT) in reducing insomnia severity, improving mood symptoms and daytime functioning (e.g. sleepiness, fatigue, cognitive function), and improving subjective and objective sleep and circadian measures compared to a waitlist control group. METHODS: We will carry out a randomised controlled trial (RCT) with 150 youths aged 12-24 who meet the criteria of insomnia and eveningness. Participants will be randomised into one of three groups: CBT-I with bright light therapy, CBT-I with placebo light, and waitlist control. Six sessions of CBT-I will be delivered in a group format, while participants will be currently asked to use a portable light device for 30 min daily immediately after awakening throughout the intervention period for bright light therapy. The CBT-I with light therapy group will receive bright constant green light (506 lx) while the CBT-I with placebo light group will receive the modified light device with the LEDs emitting less than 10 lx. All participants will be assessed at baseline and post-treatment, while the two active treatment groups will be additionally followed up at 1 month and 6 months post-intervention. The primary outcome will be insomnia severity, as measured by the Insomnia Severity Index. Secondary outcomes include self-reported mood, circadian, daytime functioning, and quality of life measures, as well as sleep parameters derived from actigraphy and sleep diary and neurocognitive assessments. Objective measures of the circadian phase using dim-light melatonin onset assessment and sleep parameters using polysomnography will also be included as the secondary outcomes. DISCUSSION: This study will be the first RCT to directly compare the effects of CBT-I and BLT in youths with insomnia and eveningness. Findings from the study will provide evidence to inform the clinical management of insomnia problems and eveningness in youths. TRIAL REGISTRATION: ClinicalTrials.gov NCT04256915. Registered on 5 February 2020.

The relationship between the morningness-eveningness questionnaire and incident cancer: A historical clinical cohort study.

OBJECTIVE: We conducted a retrospective cohort study to explore the relationship between chronotype measured by the total Morningness-Eveningness Questionnaire (MEQ) score and incident cancer. METHODS: We used clinical and provincial health administrative data on consecutive adults who underwent a Level 1 Polysomnography (PSG) and completed the MEQ between 2010 and 2015 in an academic hospital (Ontario, Canada) and were cancer-free at baseline. Cancer status was derived from the Ontario Cancer Registry. Individuals were followed until death or March 31, 2020. We used multivariable Cox cause-specific regressions to address the research objective. RESULTS: Of 3,004 individuals, 1,781 were analyzed: a median age of 54 years (IQR: 40-64) and 838 (47.1%) men. The median total MEQ score was 63 (IQR: 55-69); 61 (3.4%) were classified as evening (≤41), 536 (30.1%) as intermediate (42-58), and 1,184 (66.5%) as morning chronotypes (≥59). Over a median of 7 years (IQR: 5-8), 120 (6.7%) developed cancer. A U-shape relationship was found between the total MEQ score and an increased hazard of incident cancer, controlling for PSG measures of sleep apnea severity and sleep architecture, demographics, and comorbidities. Compared to the median of 63.0, a total MEQ score greater or less than the median was associated with an increased hazard of incident cancer, with the largest effect for those with a total score ≥76 (e.g., HR of a MEQ total score of 78 vs. 63: 2.01, 95% CI: 1.09-3.71). CONCLUSION: The U-shaped curve may reflect deviations from a standard circadian tendency, which may stress biological systems and influence malignancy risk.

Adaptation of Morningness-Eveningness Questionnaire (MEQ) in Bengali Language.

BACKGROUND: Morningness-Eveningness Questionnaire (MEQ) has been used to assess working efficiency of an individual. The self-reporting MEQ is available in English language, and its applicability to Indian scenario is limited to educated/ English proficient individuals only. Since, majority in India still depend on the regional languages for communication, it is difficult to make live translation of the questionnaire while administration and results may also vary due to tester's language proficiency. The present study focused on adapting MEQ in Bengali language. METHOD: The English version of Morningness-Eveningness Questionnaire (MEQ) was a self-assessment questionnaire consisting of 19 questions to measure whether a person's peak alertness was in the morning, evening or in between. The translation of the questionnaire was done using forward-backward-translation method by six experts in Bengali language, and was content validated by thirty native Bengali speakers. The speakers were asked to rate the questions on a 5-point rating scale with 1 being very familiar and 5 being not at all familiar. All the questions rated as 1 or 2 were considered for the Bengali version of MEQ, while those rated as 3 or above were reframed and revalidated. RESULT: The Bengali version of the MEQ has good reliability (Cronbach's alpha 0.74). Item analysis revealed it as a good consistent scale for estimating the circadian type of the participants. Participants were classified into 5 Circadian types based on the cut-off scores. Majority of participants are intermediate type, followed by Morningness. CONCLUSION: The application of MEQ will help in management of tinnitus.

Associations between chronotype and physical activity and well-being in adults.

Circadian rhythms influence a preference for people's time of activity and sleep time during the day and the hours of best performance. The aim of the study was to assess the associations between chronotype, physical activity, and well-being in adults aged 20-50. The chronotype, physical activity and well-being scores were determined based on the Composite Scale of Morningness (CSM) questionnaire, the International Physical Activity Questionnaire (IPAQ) and the Well-Being Index (WHO-5) questionnaire, respectively. Study data consisted of the answers of 213 respondents (including 64 men) who took part in an online survey. The Spearman rank correlation coefficient and the matrix scatter plots were used to check the correlations between the CSM score and quality of life parameters' values. General linear models (GLMs) were performed to find differences in quality-of-life parameters between different combinations of sex and chronotype. Morning types showed the highest value of well-being score (mean = 13.48) while evening types the lowest one (mean = 8.35). Evening types spent the most time sitting compared to other chronotypes. Results of this study revealed the significant effect of chronotype on well-being and physical activity among adults. These findings suggest that chronotype is an important factor that psychologists and personal trainers should take into account.

A more accurate assessment of circadian typology is achieved by asking persons to indicate their preferred times rather than comparing themselves with most people.

The aim of the present work was to compare two circadian questionnaires: the Preference Scale (PS) and the reduced version of the Morningness-Eveningness Questionnaire (rMEQ). A sample of 849 (35.10% men) university students, 421 of whom were Spanish (27.55% men; mean age 21.07 + 2.31) and 428 Italian (42.52% men; mean age 23.26 + 3.01), were administered both questionnaires. Gender (higher morningness in women) and nationality (higher eveningness in Spaniards) differences were replicated with rMEQ but not with PS, in which an inverse association between nationality and circadian preference was observed (i.e. higher morningness in Spaniards). Taking into account that the formulation of the rMEQ items, with its specific times, makes the answers less influenced by socio-cultural bias, we conclude that rMEQ is preferable to PS when evaluating circadian preference in young adults.

ADHD, chronotype, and circadian preference in a multi-site sample of college students.

Attention-deficit/hyperactivity disorder and an evening chronotype are both common among college students, and there is growing interest in understanding the possible link between attention-deficit/hyperactivity disorder and circadian function. However, mixed findings have been reported, and many of the existing studies have used small samples that were unable to examine chronotype across attention-deficit/hyperactivity disorder presentations. Participants were 4751 students (73% female; 80% White), aged 18-29 years (M = 19.28, SD = 1.50), from five universities who completed measures assessing attention-deficit/hyperactivity disorder, depressive and anxiety symptoms, as well as the Morningness-Eveningness Questionnaire to assess chronotype (categorical) and circadian preference (dimensional). Participants with either attention-deficit/hyperactivity disorder predominantly inattentive presentation or attention-deficit/hyperactivity disorder combined presentation had higher rates of being an evening type (47.2% and 41.5%, respectively) than participants without elevated attention-deficit/hyperactivity disorder (28.5%), and participants with attention-deficit/hyperactivity disorder predominantly inattentive presentation also had higher rates of being an evening type than participants with attention-deficit/hyperactivity disorder predominantly hyperactive-impulsive presentation (30.7%). Dimensional analyses indicated that attention-deficit/hyperactivity disorder inattentive symptoms were more strongly associated than hyperactive-impulsive symptoms with eveningness preference. Finally, greater eveningness preference strengthened the association between attention-deficit/hyperactivity disorder inattention and depressive symptoms but not anxiety symptoms. This is the largest study to document that college students with elevated attention-deficit/hyperactivity disorder symptoms are more likely to be evening types than other college students, and inattentive symptoms in particular are associated with later circadian preference.

Disruption of circadian rhythms promotes alcohol use: a systematic review.

This systematic review investigates the bidirectional relationship between alcohol consumption and disrupted circadian rhythms. The goal of this study was to identify (i) the types of circadian rhythm disruptors (i.e. social jet lag, extreme chronotypes, and night shift work) associated with altered alcohol use and (ii) whether sex differences in the consequences of circadian disruption exist. We conducted a search of PubMed, Embase, and PsycINFO exclusively on human research. We identified 177 articles that met the inclusion criteria. Our analyses revealed that social jet lag and the extreme chronotype referred to as eveningness were consistently associated with increased alcohol consumption. Relationships between night shift work and alcohol consumption were variable; half of articles reported no effect of night shift work on alcohol consumption. Both sexes were included as participants in the majority of the chronotype and social jet lag papers, with no sex difference apparent in alcohol consumption. The night shift research, however, contained fewer studies that included both sexes. Not all forms of circadian disruption are associated with comparable patterns of alcohol use. The most at-risk individuals for increased alcohol consumption are those with social jet lag or those of an eveningness chronotype. Direct testing of the associations in this review should be conducted to evaluate the relationships among circadian disruption, alcohol intake, and sex differences to provide insight into temporal risk factors associated with development of alcohol use disorder.

Chronotype influences on posttraumatic stress disorder induced by the twin earthquakes in Turkey: A cross-sectional study among medical students.

This study aimed to investigate the correlation between chronotypes and posttraumatic stress disorder (PTSD) symptoms in medical students affected by earthquakes in Kahramanmaras, Turkey, while elucidating if the PTSD manifestation varies among different chronotypes four months post-disaster. The study encompassed 193 medical students, subjected to the sociodemographic data form, the Morningness-Eveningness Questionnaire (MEQ) and the PTSD Checklist for DSM-5 (PCL-5). The results indicated that students identified as "evening types" reported significantly elevated PCL-5 scores (p < 0.001) relative to "morning" and "intermediate" types. According to PCL-5 scores, 43.5% of the participants exhibited PTSD, with a higher occurrence among the evening types. Multivariable linear regression analysis revealed that lower MEQ scores independently correlated with elevated PTSD symptoms (ß = -0.1389 [95% CI = -0.273 - -0.0048], p = 0.042), suggesting the potential of eveningness as a risk factor for PTSD post-disaster. These findings could enhance our understanding of PTSD, aid the development of preventive strategies, and underscore the importance of considering chronotypes. Further expansive, population-based studies with a longitudinal design are necessary to better understand the relationship between PTSD and the circadian system.

Is evening chronotype associated with higher alcohol consumption? A systematic review and meta-analysis.

A broader understanding of whether and to what extent chronotype should be considered a risk factor for alcohol consumption is needed. The aim of this systematic review was to summarize the evidence on the association between evening chronotype and alcohol consumption. A systematic search of observational studies on this association was conducted in the PubMed, Scopus, Web of Science, Cochrane Library and PsycINFO databases up to April 30th, 2023. Random-effect models estimated the pooled odds ratio (OR) of alcohol consumption according to chronotype. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Quality Assessment tool for Observational Cohorts and Cross-sectional Studies from the National Heart, Lung and Blood Institute were followed. A total of 33 studies involving 28 207 individuals (age range: 18-93 years) were included in this review. Overall, most studies indicated a higher volume and frequency of alcohol consumption in evening-type individuals than in individuals with different chronotypes. Additionally, a meta-analysis including 13 studies showed that evening-type individuals were 41% more likely to consume alcohol than those with other chronotypes (OR = 1.41, 95% confidence interval: 1.16-1.66; I2 = 38.0%). Limitations of the present findings are the predominance of cross-sectional studies and varied definitions of alcohol consumption. The available evidence supports an association between the evening chronotype and alcohol consumption. The evening-type population, especially young adults, is a specific target for educational interventions for preventing or reducing alcohol consumption.PROSPERO number: CRD42022343778.

Blame it on the "night owls": Perceived discrimination partly mediates the effects of morningness-eveningness on positive and negative affect.

The well-established effects of evening preference on diminished well-being and poorer mental health are usually explained in terms of common genetic bases of eveningness and negative emotionality and/or the discrepancy between biological and social clocks, experienced far more frequently by the Evening-types. However, recent studies provide evidence for the negative stereotyping of evening chronotypes which may lead to unexpectedly pronounced social stigma and its consequences. The present article provides a seminal empirical analysis of the role of perceived chronotype-related discrimination in the association between morningness-eveningness and both positive affect and negative affect. The study was conducted on a gender-balanced sample of 768 individuals aged between 18 and 56 years who filled measures of morningness-eveningness, positive and negative affect, as well as a modified version of the Perceived Devaluation Discrimination scale, tentatively labeled Perceived Chronotype-Related Discrimination scale (https://osf.io/urs8x/), developed to measure the sense of chronotype-based discrimination. Conducted analyses provided evidence for a positive association between eveningness and perceived discrimination. Moreover, perceived discrimination partly mediated the associations between morningness-eveningness and both positive affect and negative affect, explaining 18% and 29% of these effects, respectively. Hence, our results provide initial evidence for yet another mechanism through which chronotype may impact emotional functioning, namely the experience of chronotype-based stigmatisation.

Nonlinear associations between insomnia symptoms and circadian preferences in the general population: Symptom-specific and lifespan differences in men and women.

OBJECTIVES: This study investigated (non)linear associations between different eveningness characteristics (bedtime, wake time, morning affect, and peak performance time) and insomnia symptoms (difficulties initiating sleep, difficulties maintaining sleep, and nonrestorative sleep) in a large general population sample. METHODS: The data came from digital surveys about insomnia (Minimal Insomnia Scale) and circadian preferences (Children's Chronotype Questionnaire/Composite Scale of Morningness) completed by the Dutch general population (37,389 participants aged 4-91years, 42.4% men) in the Lifelines cohort substudy Comorbid Conditions of ADHD. RESULTS: Using generalized additive modeling, we found that different characteristics of eveningness related to insomnia either exponentially (later wake time/peak performance time, worse morning affect) or quadratically (early and late bedtime/midpoint of sleep). While difficulties initiating sleep and nonrestorative sleep were strongly associated with all eveningness characteristics, difficulties maintaining sleep related only to earlier bedtimes. These relationships were similar for men and women but varied partly in shapes and strengths across the lifespan. Additional analyses showed that bedtime and wake time were associated with insomnia symptoms only when their combination would result in an unusually long or short preferred time in bed. CONCLUSION: The association between eveningness and insomnia symptoms highly depends on whether eveningness is reflected by daytime performance or sleep-wake time. The pattern and strength of these associations also vary depending on age and insomnia symptom, but less so on sex. Future sleep-related research and policies relying on circadian preferences should account for the nonlinearity, dimension/symptom-related specificity and age-related differences in the association between eveningness and insomnia symptoms.

Was there a significant difference in sleep shifts in the high school population due to the COVID-19 pandemic depending on chronotype? A nationwide cross-sectional study.

The aim of this study was to detect whether the COVID-19 pandemic has caused changes in the sleep cycle (subjective sleep shifts) of high school students divided into a sample of young women - W (n = 1999, age = 17.65 ± 2.39 y) and young men - M (n = 1094, age = 17.49 ± 1.74 y) in Slovakia depending on circadian preference in comparison with the term before COVID-19. The present cross-sectional study employed a self-reported standardized questionnaire (Morningness-Eveningness Questionnaire) to study circadian preference, which was complemented by a question focused on subjective sleep shifts before and during the pandemic. The results revealed significant strong dependence between circadian preference and subjective sleep shift in both W (χ2(8) = 153.1, p < .01, Cramer's V = .20, p < .01) and M (χ2(8) = 98.3, p < .01, Cramer's V =.21, p < .01). The delay of the sleep cycle has mainly become apparent in the case of definite evening types (W: 75.7%; M: 71.8%) and moderate evening types (W: 83.1%; M: 70.3%). The delay also prevailed in the intermediate types (W: 61.9%; M: 53.8%). Subjective sleep shifts were not confirmed (W: 93.8%; M: 35.3%) in the definite morning type. The sleep cycle was changed to earlier hours of definite morning types (W: 6.3%; M: 52.9%). It is necessary to focus on definite and moderate evening types and regulate the unsuitable state to time shift of the sleep cycle.

Objective and subjective sleep in patients with non-seasonal major depressive disorder and eveningness - Results from a randomized controlled trial of bright light therapy.

STUDY OBJECTIVES: This study examines the (dis)agreement between objective and subjective sleep and their prospective changes in a randomized controlled trial of bright light therapy (BLT) in patients with major depressive disorder (MDD) and eveningness. METHODS: A total of 93 adults were randomized to receive either 30-min daily of 10,000 lux BLT or 50lux placebo dim red light therapy (DRL group) for a total of 5 weeks. Actigraphic data were collected at the baseline and during the last week of treatment. (Dis)Concordance of diary and actigraphic sleep parameters were assessed by partial correlations and Bland-Altman plots, and the associations between these discrepancies to depression severity was assessed by linear regression models. Changes of sleep parameters were assessed by linear mixed models. RESULTS: Significant correlations were found between subjective sleep timings and chronotype to actigraphic parameters. Discrepancies between diary- and actigraphic-measures were observed, and patients with more severe depressive symptoms were associated with a greater under-estimation of total sleep time (TST). A greater advance in the diary-based time to fall sleep and rise time were achieved in the BLT group as compared to the DRL group, while diary-based wake after sleep onset (WASO), TST and sleep efficiency (SE) comparably improved with time in both groups. There was no significant difference between the two groups in the actigraphic parameters after treatment. CONCLUSIONS: In this study, we found that depression severity influenced subjective report of sleep. BLT led to a greater advance in subjective sleep timings when compared to the placebo group.

Circadian preference and physical and cognitive performance in adolescence: A scoping review.

Adolescence is a crucial period of development which coincides with changes in circadian rhythmicity. This may augment the impact of circadian preference on performance in this group. We aimed to scope the literature available on chronotypes and their effect on physical and mental aspects of performance in adolescents. Studies were identified by systematically searching bibliographical databases and grey literature. The Morningness-Eveningness Questionnaire was the most frequently reported tool for circadian preference assessment. Academic achievement was the most prevailing outcome, with evidence suggesting that morning type adolescents tend to outperform evening types, yet the results vary depending on multiple factors. Performance in tests of intelligence and executive functions was generally better at optimal times of the day (synchrony effect). Physical performance was examined in 8 studies, with very heterogeneous outcomes. Although the associations between circadian preference and performance in adolescents are evident in some areas, there are many factors that may be involved in the relationship and require further investigation. This review highlights the assessment of physical performance in relation to chronotypes, the multidimensional assessment of circadian preference, and the need for longitudinal studies as priorities for further research.Protocol: OSF Registration - Public registration, DOI: 10.17605/OSF.IO/UCA3Z.

The effect of circadian preference and sleep disturbances on depression in children 6 to 12 years of age.

Circadian rhythm and sleep disruption have been associated with depressive symptoms in children. This study was conducted to determine sleep disturbances and circadian preferences and their possible associations with depression in healthy children 6 to 12 years of age. A total of 111 healthy children (mean age 7.5 years; 62.2% male) were included. Sleep disturbances and depression were determined by the Sleep Disturbance Scale for Children (SDSC) and the Children's Depression Inventory (CDI), respectively. Circadian preference was evaluated by the Morningness - Eveningness Stability Scale improved (MESSi). SDSC was correlated with CDI (r = 0.396, p < 0.001). Morning affect was inversely correlated with CDI (r = -0.405, p < 0.001), SDSC (r = -0.348, p < 0.001), and three subdimensions of SDSC, i.e. disorders of initiating and maintaining sleep (DIMS, r = -0.317, p = 0.001), disorders of arousal (DA, r = -0.375, p < 0.001) and disorders of excessive somnolence (DOES, r = -0.303, p = 0.001). Distinctness was inversely correlated with CDI (r = -0.402, p < 0.001) and SDSC (r = -0.274, p < 0.001). Increased use of electronic devices was associated with higher CDI (p = 0.003), while decreased duration of physical activity with higher SDSC (p = 0.017). Our findings support the recommendations addressing sleep and circadian preferences as lifestyle modifications in reducing depression in children.

Correlation Analysis Between Time Awareness and Morningness-Eveningness Preference.

The circadian clock is adjusted by light inputs via the retinohypothalamic tract. Because environmental light is controllable for modern humans at the individual's preference although under social schedules, individual differences in time-related psychology and behavior may be associated with morningness-eveningness preference (M-E preference). To examine this hypothesis, we used the Time Management Scale and Time Anxiety Scale to quantify time-related psychology and behavior. These scales aim to evaluate "awareness of effective time management and utilization" and "anxiety about uncontrollable time schedule and unexpected time-related outcome", respectively. According to our correlation analysis using mid-sleep time as a marker for M-E preference, we obtained results supporting our hypothesis in the correlation between the M-E preference values and the Time Management Scale scores, with larger "time estimation" and "taking each moment as it comes" scores associated with more morningness and eveningness, respectively. Considering that modern humans likely become night owls under artificial light conditions, it appears plausible that lower awareness of time management leads to more eveningness.

Sprint and jump performances of female athletes are enhanced in the evening but not associated with individual chronotype.

Sprint and jump performances represent performance-determining parameters in individual and team sports. Fluctuations in performance depending on the daytime raise the question of the best time to train and compete. Given the scarce research on females, this study aimed to analyze the influence of daytime on sprint and jump performances and to investigate whether the performance difference is related to the chronotype. Thus, 23 female sports students completed a questionnaire to assess their chronotype followed by performing two 30 m sprints, 5 Repeated Jump Tests (5RJT), and countermovement jumps (CMJ) in the morning (7:00-9:00 h) and evening (17:00-19:00 h). Time after 5 m, 10 m, and 30 m during the sprints, reactive strength index (RSI) during the 5RJTs, and jump height during the CMJs were examined. The performance during the 30 m sprint (t(22) = 5.28, p < 0.01 moderate effect size: 0.50) and the two jump tests (5RJT: t(22) = 8.27, p < 0.01 large effect size: 0.95; CMJ: t(22) = 5.46, p < 0.01 moderate effect size: 0.79) were significantly better in the evening than in the morning. There was no significant correlation between chronotype and the time-of-day effect. The results should be considered when planning training and competition.

Chronotype is associated with addiction-like eating behavior, mindful eating and ultra-processed food intake among undergraduate students.

This study aimed to investigate the relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food consumption among undergraduate students. Specific and validated scales were used in order to evaluate chronotype, addiction-like eating behavior and mindful eating (N = 605). Dietary intake was determined by food frequency questionnaire and percentage energy from ultra-processed food was calculated. Self-reported weights and heights were obtained from the participants. Mean scores of scales, social jetlag, energy intake, ultra-processed food intake and BMI were compared by chronotypes. Associations between chronotype, addiction-like eating behavior, mindful eating, ultra-processed food consumption and BMI were determined by Pearson's test. The relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food intake were assessed by linear regression models and adjusted for sex, BMI, energy intake, season, smoking and alcohol consumption. Evening-type participants had higher scores of social jetlag (2.01 ± 0.09), appetitive drive (26.02 ± 0.63), low dietary control (20.50 ± 0.41), addiction-like eating behavior (46.52 ± 0.85), lower scores of recognition (21.91 ± 0.43) and higher percentage energy from ultra-processed food (32.24 ± 1.26%). Chronotype score showed negative associations with addiction like eating behavior (ß=-0.247, p < 0.001) and ultra-processed food consumption (ß=-0.247, p < 0.001), and a positive association with recognition (ß = 0.124, p < 0.001). Results suggest that chronotype is inversely associated with addiction-like eating behavior and ultra-processed food consumption, and positively associated with mindful eating among undergraduate students.