Recent studies show that tactical knowledge acquisition from dynamic visualizations fluctuates across the day, with a morning advantage over afternoon sessions. However, these investigations relied exclusively on concurrent presentation of information. It remains unknown whether these findings hold when learners receive sequential presentation of information. We addressed this gap by examining how concurrent versus sequential presentation of soccer animations affects tactical knowledge acquisition at different times of day. Fifty sport science undergraduates (Mage = 18.4 ± 1.2 y) voluntarily participated. They completed morning (08:00 h-09:00 h) and afternoon (16:00 h-17:00 h) sessions, studying animated counterattacks in either concurrent or sequential format, followed by an immediate recall test. Heart rate and feeling states were measured at the start of each session. Recall accuracy was higher in the morning than in the afternoon for both groups. This morning advantage was accompanied by lower heart rate and more positive feelings. Diurnal changes in recall accuracy correlated negatively with heart rate and positively with feeling states. Sequential presentation of information led to better recall than concurrent presentation at both times of day, with no interaction between format and time of day. These findings suggest that, pending replication in more ecologically valid settings, physical education teachers may consider using sequential presentation of information in soccer animations - particularly during morning sessions - when communicating tactical instructions to novice learners.
This study systematically examined temporal dynamics in subjective states and cognitive performance using time‑of‑day protocols in both laboratory and real work settings. Twenty-four participants completed the field study and twenty‑one participants completed the laboratory study, with their self-reported sleepiness, vitality and mood being assessed at seven time points (08:30 h, 09:30 h, 11:00 h, 13:40 h, 14:30 h, 16:00 h, 17:30 h) and performance on sustained attention, executive inhibition and working memory being measured at six time points (08:30 h, 09:30 h, 11:00 h, 14:30 h, 16:00 h, 17:30 h). Results showed a significant time-of-day effect in subjective sleepiness and vitality, with a notable post-lunch decline (13:40 h-14:30 h) being more pronounced in real work environment. Subjective mood rendered more pronounced diurnal variations in natural settings, with positive mood being significantly lower at 16:00 h compared to 08:30 h and 09:30 h. Regarding cognitive performance, sustained attention showed optimal performance in the morning, whereas better working memory was observed in the afternoon, and executive inhibition showed minimal diurnal variation. Overall, cognitive performance exhibited greater variability in the real work environment than in the laboratory. The differences in finding between the laboratory and real work setting and the practical recommendations for optimizing subjective well-being and work efficiency in workplace have been discussed.
Circadian and sleep-wake dysregulation have been implicated in episode recurrence and clinical heterogeneity in bipolar disorder (BD), supporting peripheral circadian markers as candidates for further investigation. This study examined the peripheral expression of selected circadian rhythm-related gene mRNAs and antisense long non-coding RNAs (lncRNAs), alongside corresponding serum protein levels and self-report-based rhythm phenotyping, in euthymic patients with BD. Sixty euthymic patients with BD (20 BD-1, 20 BD-2, and 20 with antidepressant-associated hypo/manic switch [ASHH], treated as an exploratory group) and 20 healthy controls were enrolled. Euthymia was verified by HAM-D < 7 and YMRS < 6, and chronotype and rhythm phenotypes were assessed using the MEQ, SRM-5, and BRIAN. Morning fasting blood was collected (08:00-10:00) with the morning medication dose withheld; because sampling was confined to a single morning window, the reported values represent morning transcript abundance rather than circadian rhythmicity, amplitude, or phase position. Three core clock gene mRNAs (CIART, ARNTL, CLOCK) and two antisense lncRNAs (CRY1AS, PER2AS) were quantified by qRT-PCR (2^-ΔΔCt, β-actin reference), and serum CIART, CRY1, PER2, and ARNTL proteins were measured by ELISA. Between-group comparisons used nonparametric tests (Mann-Whitney U; Kruskal-Wallis H with Bonferroni post hoc), and correlations used Spearman's coefficient with Benjamini-Hochberg FDR correction. Compared with healthy controls, patients showed statistically significantly higher expression of the lncRNAs PER2AS (r = 0,57) and CRY1AS (r = 0,49) and the mRNAs CIART (r = 0,35) and CLOCK (r = 0,29), all p ≤ 0,007, whereas ARNTL mRNA did not differ (p = 0,654). In exploratory subgroup analyses, differences were concentrated in BD-2 and ASHH: BD-2 showed the highest expression and BD-1 the lowest, with BD-1 not differing from controls for any marker. Serum protein levels did not differ between groups or subgroups, and MEQ, BRIAN, and SRM-5 scores did not differ; however, a sensitivity analysis excluding shift workers revealed a chronotype difference masked in the full sample. Across 174 correlational tests, none survived FDR correction (lowest q = 0,063); nominal uncorrected associations are reported as preliminary only. In euthymic BD, peripheral expression of selected circadian rhythm-related markers-particularly the antisense lncRNAs PER2AS and CRY1AS and the mRNAs of CIART and CLOCK - differed from healthy controls, whereas corresponding serum protein levels and behavioral rhythm phenotypes did not. This divergence across measurement levels can be considered a substantive finding, and the subgroup patterns are exploratory and hypothesis-generating. Longitudinal, episode-inclusive, and subtype-stratified studies incorporating objective circadian phase markers and repeated sampling are needed to establish the significance of peripheral transcript-level differences in BD.HIGHLIGHTS Peripheral circadian gene mRNAs and antisense lncRNAs are profiled in euthymic bipolar subtypes.PER2AS and CRY1AS lncRNAs and CIART and CLOCK mRNAs are higher in patients than controls.Exploratory analyses: transcript differences concentrate in BD-2 and ASHH; not BD-1.Serum CIART, CRY1, PER2, and ARNTL protein levels by ELISA do not differ by group.Behavioral rhythm scores do not differ; correlations do not survive FDR correction.
Insufficient sleep has been linked to an increased risk of gastric diseases among middle-aged and older adults. However, prospective evidence on the relationship between sleep duration and the incidence of gastric diseases remains limited. This study aimed to investigate the longitudinal associations of nighttime sleep and daytime nap duration with the risk of new-onset gastric diseases in an elderly Chinese population. Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS), conducted from 2011 to 2020. A total of 7,539 participants aged ≥ 45 y and free of gastric diseases at baseline were included and followed for up to 9 y. Nighttime sleep duration and daytime nap duration were collected through self-reported questionnaires at baseline. Cox proportional hazards models were used as the primary analysis to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Multiple logistic regression models were employed for predictive metrics (C-statistic, continuous Net Reclassification Improvement [NRI], and Integrated Discrimination Improvement [IDI]). Restricted cubic spline analyses were employed to explore the dose-response relationship between sleep duration and the risk of new-onset gastric diseases. Among the 7,539 individuals included in the cohort, 1,452 (19. 3%) were diagnosed with new-onset gastric diseases. Participants with shorter nighttime sleep duration had a significantly higher risk of developing gastric diseases. Specifically, each interquartile range increase in nighttime sleep duration was associated with a 14% reduction in risk (HR: 0. 86; 95% CI: 0. 79-0. 95). Compared to those in the shortest sleep quartile, participants in the longest quartile experienced an approximately 20% lower risk (HR: 0. 80; 95% CI: 0. 64-1. 01; p = 0. 06). No significant association was found between daytime nap duration and the incidence of gastric diseases. Stratified analyses yielded consistent results across demographic and clinical subgroups, with stronger associations observed among females, married individuals, and rural residents. Shorter nighttime sleep duration was independently associated with an increased risk of new-onset gastric diseases in middle-aged and older adults. In contrast, daytime napping showed no significant relationship with gastric disease risk. These findings underscore nighttime sleep duration as a potentially modifiable factor for gastric disease prevention among older populations.
Modern lifestyle changes have contributed to a marked increase in myopia and visual impairments in recent decades. However, the systemic biological effects and underlying mechanisms of prolonged exposure to different artificial light sources remain poorly understood. To address this gap, two-week-old female guinea pigs were randomly assigned to three groups: an indoor natural light (IN) control group, a light-emitting diode (LED) group, and a screen video (SV) group. Animals were maintained under a 12:12-h light-dark cycle (lights on 08:00 h, lights off 20:00 h) for 12 weeks. Ocular axial length, peripheral hormone profiles, and systemic glucose-lipid metabolism were evaluated across the three lighting environments. Compared with the IN group, both the LED and SV groups exhibited significant ocular axial elongation, dysregulated lipid metabolism, and altered endocrine profiles. Retinal expression of melanopsin - the photopigment in intrinsically photosensitive retinal ganglion cells (ipRGCs) that regulates non-image-forming visual functions and circadian photoentrainment - was significantly upregulated in the artificial light groups. Molecular analyses further revealed downregulation of key reproductive and metabolic genes (Gnrh1, Cyp17a1, and Flt4) alongside upregulation of hypothalamic circadian clock genes and Kiss1. These findings suggest that artificial light spectra elevate retinal melanopsin expression, which, combined with altered hypothalamic clock gene activity, disrupts reproductive, and metabolic homeostasis. This work highlights a potential role for melanopsin-mediated non-image-forming pathways in light-induced endocrine and metabolic disorders, warranting further mechanistic investigation.
This study aimed to characterize and compare the differences in circadian rhythm changes during 2 years between college students with myopia and non-myopia based on a longitudinal cohort study. Wake-up time and bedtime were obtained through a self-administered questionnaire. Chronotype was assessed using the reduced Morningness-Eveningness Questionnaire (rMEQ). Circadian rhythm timing was determined by dim-light melatonin onset (DLMO), measured through hourly saliva collection from 21:00 to 01:00. A total of 450 college students (146 [32.4%] males) with a mean age of 18.65 ± 1.05 years were included, of whom 353 (78.4%) students had myopia. Compared with non-myopic individuals, myopic students slept later, woke up earlier, and exhibited lower rMEQ scores at baseline. Over the 2-year follow-up, both groups showed significantly earlier bedtimes, later wake-up times, and higher rMEQ scores. Only myopic students demonstrated a 45-minute delay in DLMO after the 2-year follow-up. After adjusting for potential confounders, linear mixed-effects models showed that myopic individuals had later bedtimes and earlier wake-up times. These findings indicate significant circadian rhythm changes in individuals with myopia, suggesting the potential of targeted sleep rhythm interventions on preventing myopia.
Opioid Use Disorder (OUD) carries a high risk of psychiatric comorbidities, such as depression, sleep disturbances and suicidal behaviour. Recent findings emphasise the impact of chronotype and biological rhythm disturbances on the severity of addiction and suicidality. This study examined the associations between chronotype, biological rhythm characteristics, sleep quality, depressive symptoms and suicidal behaviour in individuals with OUD. A total of 159 patients diagnosed with OUD and 154 healthy controls were evaluated using validated scales, including the Columbia Suicide Severity Rating Scale, Biological Rhythm Assessment Interview, Morningness-Eveningness Questionnaire, Pittsburgh Sleep Quality Index, Beck Depression Inventory and Addiction Profile Index. The results showed that individuals with OUD had significantly higher rates of suicidal ideation and attempts, poorer sleep quality, more irregular biological rhythms and more severe depressive symptoms than the control group. An evening chronotype was more prevalent in the OUD group and was associated with greater addiction severity, disrupted rhythms, poor sleep quality, and increased suicidality. Higher depression severity was significantly associated with lower morningness preferences, and sleep quality was found to explain a significant portion of the shared variance between depressive symptoms and suicidal outcomes. These findings suggest that assessing chronotype and circadian dysregulation could help to identify high-risk patients and inform the development of targeted interventions to improve outcomes in OUD treatment.
Chronotype and meal timing are associated with sleep, yet their joint relationships remain understudied in physically active university students. This study investigated associations among chronotype, caloric intake timing, and sleep characteristics and hypothesized that later first and last caloric intake would independently predict lower Morningness-Eveningness Questionnaire (MEQ) scores. This single-university cross-sectional study included 200 students aged 18-25 years who had exercised ≥3 days/week and ≥150 min/week for the preceding six months. Chronotype, sleep behavior, sleep characteristics, and dietary intake timing were assessed using the MEQ, Athlete Sleep Behavior Questionnaire, three-day sleep diary, and three-day food record, respectively. Multiple linear regression evaluated continuous MEQ score as the primary outcome; group comparisons and correlations were secondary or exploratory. A dummy-coded model tested the robustness of the meal-timing results. Later first and last caloric intake were independently associated with lower MEQ scores (β = -0.435 and -0.422, respectively; both p < 0.001), and the model explained 51.1% of the variance. The sensitivity analysis showed the same graded pattern. Evening-type participants had poorer sleep behaviors, longer sleep latency, lower sleep efficiency, more nocturnal awakenings, poorer subjective sleep quality, and later caloric intake than morning-type participants (all p < 0.001). Total energy and macronutrient intake were unrelated to the evaluated sleep outcomes. Later caloric intake timing was independently associated with greater eveningness, while evening chronotype co-occurred with less favorable sleep characteristics. Given the cross-sectional design, causality and temporal direction cannot be inferred.
Women and evening (late) chronotypes more often than men and morning (early) chronotypes report problems with health, mood, and sleep. Can we expect that, in turn, women report evening preference more often than men? Instead, the literature on chronotypes suggests that men report a slightly larger evening preference than women. To explain this paradoxical finding, we investigated the role of morning and evening components of earliness-lateness. Previous studies have shown that preferences for earliness-lateness (i.e. morningness-eveningness) can vary depending on whether the morning or evening hours are considered. Therefore, we tested the following hypotheses: 1. Sex is unrelated to the combination of lateness in the morning hours with lateness in the evening hours because women more often than men combine morning lateness with evening earliness rather than with evening lateness. 2. Only morning lateness is associated with sleep, mood, and health problems, while evening lateness is not. Paired assessments of morning and evening earliness-lateness and problems with health, mood, and sleep were reported by 439 male and 1143 female university students. We examined relationships between these problems, sex, morning lateness, evening lateness, and their combination. Results supported the study hypotheses. Evening lateness did not contribute to the link of combination of morning and evening lateness to health, mood, and sleep problems and 2) this combination was unrelated to sex of students. Namely, female students less often than male students reported evening lateness that did not contribute to the association of combination of morning and evening lateness with health, mood, and sleep problems. Instead, they more often reported morning lateness that was also associated with health, mood, and sleep problems. As a result, they more often reported problems with health, mood, and sleep, while sex of students was not related to combination of morning lateness with evening lateness (i.e. with morning-evening preference).
Daylight exposure is an environmental determinant of human health, yet measuring real-world exposure at scale remains a major challenge. Large population studies frequently rely on self-reported time spent outdoors as a proxy for daylight exposure, although the validity of this measure remains uncertain. We evaluated the agreement between daily self-reported outdoor daylight exposure and objective light measurements obtained from wearable sensors and investigated whether depressive symptoms influence this agreement. A total of 172 adults living in two Brazilian metropolitan regions were monitored for up to 44 consecutive days, yielding over 5,800 matched days of subjective and objective exposure data. Objective measures included device output illuminance, photopic illuminance, and melanopic equivalent daylight illuminance (EDI). Agreement was assessed across the light exposure thresholds and durations using Lin's concordance correlation coefficient and ROC analyses. Moderate agreement was observed between self-reported and actigraphy-based daylight exposure. The highest concordance occurred at light levels consistent with outdoor daylight (>1000 l× for photopic illuminance and melanopic EDI; >750 l× for device illuminance). A minimum of 30 min of outdoor daylight exposure was the duration most accurately self-reported. Depressive symptoms did not affect these agreement patterns. These findings support the use of simple self-report questionnaires to estimate outdoor daylight exposure in clinical applications and in studies examining how environmental factors shape health.
The circadian system regulates physiological and metabolic processes, and exercise timing may influence metabolism and adiposity. To investigate the time-of-day effects of high-intensity interval resistance training (HIRT) on metabolism, adiposity, and adipogenic markers, male Swiss mice (n = 111) were allocated to control or HIRT groups during the light (C6 and T6) or dark phase (C18 and T18). HIRT was performed for 8 weeks (3 sessions/week) on a ladder at 90% of maximal load until exhaustion. Metabolic biomarkers, adiposity, adipocyte morphology, and protein expression of PPARγ and adiponectin were assessed. Maximal strength increased in trained groups. Training-time interactions were observed for triglycerides and total cholesterol, with higher values in T6 than in C6 and T18. Glucose and PPARγ were higher during the dark phase. PPARγ was also higher in trained than control groups, irrespective of the time of day. HIRT reduced adiposity across multiple depots regardless of training time. No significant differences were observed for adipocyte area, adiponectin, insulin, or HOMA-IR. HIRT reduced adiposity independently of training time, suggesting that chronic adaptations in adipose tissue were primarily driven by the training. However, time of day modulated metabolic responses, particularly lipid metabolism.
Chronotype and social jetlag are important correlates of sleep and health, yet their joint relationship with somatic symptom burden remains insufficiently studied in medical students. This cross-sectional study examined the associations among chronotype, social jetlag, sleep quality, and somatic symptoms in 500 undergraduate medical students aged 18-26 y. Chronotype was assessed with the Morningness-Eveningness Questionnaire (MEQ), sleep quality with the Pittsburgh Sleep Quality Index (PSQI), social jetlag (SJL) from weekday-weekend mid-sleep differences, and somatic symptoms with the DSM-5 Level 2-Somatic Symptom-Adult scale. Higher morningness was associated with lower social jetlag, better sleep quality, and fewer somatic symptoms. Social jetlag was positively associated with poorer sleep quality and higher somatic symptom scores, whereas sleep quality showed the strongest association with somatic symptoms. In multivariable analyses, higher morningness predicted lower social jetlag and better sleep quality, and greater social jetlag independently predicted poorer sleep quality. However, after accounting for sleep quality, neither chronotype nor social jetlag remained independently associated with somatic symptoms. Serial mediation analysis showed that the chronotype-somatic symptom association was largely accounted for by indirect pathways, predominantly through sleep quality, with an additional smaller serial pathway through social jetlag and sleep quality.
The phase delay on the sleep-wake cycle resulting from biopsychosocial changes related with adolescence is exacerbated by the level of urbanization. However, early school start times conflict with this delay, leading to several negative consequences. This study aims to compare sleep habits and quality, daytime sleepiness, and attention between adolescents from morning and afternoon shifts across different urbanization levels. A total of 159 Brazilian adolescents from technical high school (15.3 ± 0.8 years old; 101 girls/58 boys) completed the following questionnaires: "Health and Sleep," the Pittsburgh Sleep Quality Index, and the Pediatric Daytime Sleepiness Scale, in addition to a 10-d sleep diary that included the Maldonado Sleepiness Scale. Attention was evaluated by a continuous performance task. Sleep and attention were compared between shifts (Morning: n = 78/Afternoon: n = 81) and degrees of urbanization (High: n = 97/Low: n = 62) using MANCOVA. Independent of urbanization level, morning-shift students woke-up earlier, had a shorter time in bed at night and over a 24-h period (nocturnal sleep + nap), showing higher irregularities in wake-up times, along with higher sleep debt at night and over 24-h, social jetlag, daytime sleepiness, sleepiness upon wake-up time, frequency of naps, and non-spontaneous waking during the week than those in the afternoon shift. However, there were no differences in attention performance. Independent of shift, students from higher urbanization regions showed later bed and wake-up times and a shorter time in bed at night and over 24 h on weekends, and higher sleepiness upon wake-up time on weekdays. Despite longer reaction time in phasic alertness and selective attention, they showed a lower percentage of wrong responses in tonic and phasic alertness, selective attention, and a higher time‑on‑task stability. Thus, early school starting time is a strong modulator for adolescents' sleep-wake cycle regardless of the urbanization level. Further studies are necessary to analyze the relationship between attention and school shift.
Dynamic alterations in the bioelectrical activity of the atrial myocardium exhibit annual variation, a phenomenon that remains largely unexplored in women. This study aimed to investigate the influence of climate on the annual and seasonal dynamics of P-wave amplitude and duration, P-Q duration, and heart rate (HR). The study cohort comprised 313 apparently healthy women (age 40.9 ± 2.1 y) residing in the European North (62° N, 51° E). Electrocardiograms were recorded monthly using the standard 12-lead configuration. Annual drift in P-wave amplitude was observed in leads I - and V4-6 (p < 0.05-0.001). The P-wave amplitude was significantly greater in winter (December‒February) than in autumn (September‒November): 0.076 ± 0.037 mV and 0.061 ± 0.023 mV, respectively, representing a 56.5% increase (p < 0.001). Grouped by season the amplitudes of the P wave were the lowest in autumn (0.061 + 0.023 mV), then increased in winter (0.076 + 0.037 Mv) by 24.6% (p < 0.001). P-Q segment duration, P-Q interval duration, P-wave duration, and HR did not differ seasonally (p > 0.05). During the winter, the P-wave amplitude correlated with the ambient temperature (-0.254, p < 0.05), whereas in autumn, it correlated with the relative humidity (-0.213, p < 0.05). These findings suggest that variability in P-wave amplitude in healthy women is associated with adaptive responses to meteorological variations throughout the year.
Although chronovaccination - controlling the time of day of vaccination (TODV) to enhance protective immunity - has been described as a potential paradigm shift in vaccine immunology, unequivocal evidence for clinical benefit outweighing other societal and practical considerations has yet to be established. The current mixed evidence for chronovaccination providing an additional competitive edge to vaccine effectiveness is likely due to complex population-level interactions between various circadian, environmental, and sociodemographic factors influencing antibody responses to vaccines. Nonetheless, TODV shows the greatest potential for sub-cohorts of populations, particularly older age, and immunocompromised groups. In these contexts, this review provides a Person, Place, and Time consideration of the factors influencing the outcomes of chronovaccination studies.
Sleep and circadian rhythm disturbances are common clinical features in people with multiple sclerosis (PwMS) and related demyelinating conditions. Affective symptoms may shape vulnerability to circadian dysregulation. This pilot cross-sectional study examined how affective symptoms and underlying temperamental dispositions relate to circadian rhythm instability in a population of newly diagnosed PwMS and related demyelinating conditions, defined as patients evaluated within 30 days after discharge from the index hospitalization during which the diagnosis was established. Measures included Beck Depression Inventory-II (BDI-II), State-Trait Anxiety Inventory (STAI-Y), Biological Rhythm Interview for Assessment in Neuropsychiatry (BRIAN), Morningness-Eveningness Questionnaire, and brief Temperament Evaluation of Pisa, Memphis, and San Diego. Pearson correlations explored associations among circadian, affective, and temperament dimensions. A multiple linear regression tested independent psychopathological variables associated with BRIAN total scores. In our sample (n = 77; mean age 33 y; 71% women; 81.8% relapsing-remitting MS), clinically relevant depressive symptoms were present in 22%, and state/trait anxiety in 46% and 41% PwMS, respectively. Circadian dysregulation (BRIAN ≥ 40) showed a prevalence of 13.7%. BRIAN scores correlated with BDI-II (r = .68), STAI-Y1/Y2 (r = .55-.60), and depressive/cyclothymic/anxious/irritable temperaments (r = .37-.42). In the regression model (adjusted R2 = .521), depressive symptom severity displayed the strongest association with circadian disruption (β = .562, p < 0.001), with a smaller contribution of depressive temperament (β =-.385, p = 0.017). Both current affective symptoms and underlying temperamental traits may contribute to circadian rhythm instability in MS. Systematic assessment of mood and circadian rhythms may offer a more comprehensive framework for identifying clinically relevant chronobiological disruption in these patients.
This study assessed the impacts of stocking density on growth and locomotor activity (LA) of lambs in the suckling and fattening periods, integrating production variables with behavioural and circadian rhythm analyses. Lambs were reared under either high or low stocking densities (suckling period: high, 2.1; low, 7.3 m2/ewe; fattening period: high 1.4; low 2.6 m2/lamb), and growth performance was assessed separately for suckling and fattening periods. LA was recorded by accelerometers, and circadian rhythms were characterised by a 24-h cosinor analysis. In the suckling period, stocking density had a significant effect on amplitude and acrophase of LA. In the fattening period, lambs exhibited a robust circadian rhythm in LA at both densities, similar mean MESOR and acrophases; however, lambs housed at high density at both studied periods had a significantly higher amplitude than did lambs at low density. Differences between groups in growth performance observed in the suckling period tended to diminish in the fattening period, suggesting that compensatory growth occurred once nutritional constraints were removed. The results have demonstrated that stocking density influences LA in a phase-dependent manner and that circadian indicators provide complementary insights into the biological responses of lambs to housing conditions, beyond those obtained from growth performance alone.
Adolescence involves pronounced changes in sleep timing and duration that have been linked to executive functioning, impulsivity, and risk behaviors, yet evidence for generalizable sleep - self-regulation associations remains limited. We used regularized canonical correlation analysis to examine multivariate relationships between sleep and self-regulation across two independent cohorts. In the Adolescent Brain Cognitive Development study (n = 11,143), later chronotype and shorter sleep duration were associated with higher impulsivity, particularly urgency and deficits in planning and perseverance (r = 0.21, permutation p < 0.001), with minimal contribution from delay discounting. Social jetlag showed weak loadings. In the National Consortium on Alcohol and Neurodevelopment in Adolescence cohort (n = 831), only one canonical function was statistically significant (r = 0.15, p = 0.011), characterized by later chronotype and greater social jetlag, with minimal contribution from sleep duration and primary loadings on impulsivity-related measures. Applying the ABCD-derived sleep - self-regulation pattern to NCANDA produced a small but nonzero association, driven primarily by social jetlag and delayed sleep timing, with minimal influence of sleep duration. These findings provide multivariate evidence linking delayed sleep timing and circadian misalignment to adolescent self-regulation, though effect sizes attenuate across cohorts. Longitudinal work is needed to clarify predictive pathways and inform sleep-focused interventions during this vulnerable developmental period.
