Search Results (257)

Chronotype, an individual’s preferred timing of sleep and activity within a 24 h cycle, significantly influences metabolic health, muscle function, and body composition. This review explores the interplay between circadian rhythms, hormonal fluctuations, and behavioral patterns—such as nutrition timing, physical activity and sleep quality—and their impact on muscle mass, strength, and quality. Evening chronotypes (ETs) are consistently associated with poorer sleep, irregular eating habits, reduced physical activity, and increased risk of obesity, sarcopenia and metabolic disorders compared to morning types (MTs). At the molecular level, disruptions in circadian clock gene expression (e.g., BMAL1, PER2, CRY1) affect protein synthesis, insulin sensitivity, and energy metabolism, contributing to muscle degradation and impaired recovery. The review highlights critical components—targeting chrono-nutrition, sleep quality, and exercise timing—to align lifestyle behaviors with circadian biology, thereby preserving muscle health and improving overall metabolic outcomes. Full article

The circadian cycle regulates metabolism in response to external stimuli, such as light exposure, sleep schedules, and eating patterns. However, misalignment between internal biological rhythms and social demands can compromise food choices, potentially leading to overweight and obesity. This research aimed to assess how a person’s chronotype links to social jet lag (SJL), which in turn would relate to their nutritional status and food consumption patterns as a university student. 617 students from a State University located in the State of Paraná, Brazil, completed a cross-sectional research study that collected sociodemographic information/anthropometrics by means of an online survey. It included self-reported height/weight data and dietary habits. The Munich Chronotype Questionnaire (MCTQ) was utilized to determine each participant’s chronotype classification and SJL calculation. Researchers found that nearly half of the students (49.3%) displayed an Intermediate Chronotype, which is associated with a diet that contained elements of the “Mixed” Diet, meaning there are equal portions of healthy food (Fresh Fruits, Beans, etc.) and unhealthy foods (Sweetened Beverages). The multivariate logistic regression analyses identified age as a significant predictor of obesity risk (OR: 1.15, p < 0.001), while dietary habits such as fruit consumption played a protective role. Additionally, having a breakfast protected them from being classified as obese compared to those who did not eat breakfast (OR = 0.59). Contrary to expectations, late-night supper was not a statistically significant predictor in the adjusted model. Predictors of an Intermediate chronotype included being male and eating morning snacks regularly. The results of this study suggest that students with an intermediate chronotype will predictably have skewed eating patterns, such as skipping breakfast and eating late—both of which affect obesity risks. Nutritional strategies for university students should focus on promoting circadian regularity and optimizing meal timing. Full article

The prevalence of binge-eating behavior among individuals with obesity is reported to be higher than in the overall population. Previous studies have suggested that chronotype (more specifically, eveningness) is associated with binge-eating symptoms; however, this association remains unclear among individuals with obesity. Background/Objectives: To evaluate the association between chronotype and binge-eating symptoms in adults with severe obesity undergoing preoperative evaluation for bariatric surgery. Methods: This cross-sectional study evaluated 100 adults with severe obesity undergoing multidisciplinary preoperative assessment at a bariatric surgery clinic. Binge-eating symptoms were assessed using the Binge-Eating Scale. Chronotype was evaluated using the Morningness–Eveningness Questionnaire. Other sleep parameters were subjectively assessed using the Insomnia Severity Index, the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index, the Functional Outcomes of Sleep Questionnaire, and the Berlin questionnaire. Psychological aspects were assessed using the Depression, Stress, and Anxiety Scale (DASS-21). Results: Clinically relevant binge-eating symptoms were identified in 50% of the patients. Regarding chronotype, 16 patients were evening-types, 45 were intermediate types, and 39 were morning-types. The proportion of the clinical sample with moderate or severe binge-eating symptoms was equivalent among the three chronotypes (p = 0.794), with patients with no binge-eating symptoms accounting for around 50% of each group. There was no association between chronotype and the binge-eating score (p = 0.702). Conclusions: Despite the high prevalence of binge-eating symptoms and an overall negative sleep profile (composed of excessively daytime sleepiness, poor sleep quality, and a high risk of sleep apnea), chronotype does not appear to influence binge-eating symptoms in this clinical sample of adults with severe obesity evaluated for bariatric surgery. These findings suggest a limited utility of chronotype assessment for identifying vulnerability to binge-eating symptoms in the preoperative setting. Full article

Background/Objectives: Chrononutrition—the temporal organization of food intake relative to circadian rhythms—has emerged as an important factor in cardiometabolic health. While meal timing is typically analyzed as an isolated variable, limited research has examined integrated meal timing patterns, and no study has systematically compared clustering approaches for their identification. This cross-sectional study compared four clustering techniques—traditional (K-means, Hierarchical) and non-traditional (Gaussian Mixture Models (GMM), Spectral)—to identify meal timing patterns from habitual breakfast, lunch, and dinner times. Methods: The sample included 388 Mexican university students (72.8% female). Patterns were characterized using sociodemographic, anthropometric, food intake quality, and chronotype data. Clustering method concordance was assessed via Adjusted Rand Index (ARI). Results: We identified five patterns (Early, Early–Intermediate, Late–Intermediate, Late, and Late with early breakfast). No differences were observed in BMI, waist circumference, or age among clusters. Chronotype aligned with patterns (morning types overrepresented in early clusters). Food intake quality differed significantly, with more early eaters showing healthy intake than late eaters. Concordance across clustering methods was moderate (mean ARI = 0.376), with the highest agreement between the traditional and non-traditional techniques (Hierarchical–Spectral = 0.485 and K-means-GMM = 0.408). Conclusions: These findings suggest that, while traditional and non-traditional clustering techniques did not identify identical patterns, they identified similar core structures, supporting complementary pattern detection across algorithmic families. These results highlight the importance of comparing multiple methods and transparently reporting clustering approaches in chrononutrition research. Future studies should generate meal timing patterns in university students from other contexts and investigate whether these patterns are associated with eating patterns and cardiometabolic outcomes. Full article

Poor coping among university students is widespread globally, yet few studies examine whether modifiable lifestyle risk factors are associated with this phenomenon. This study aims to assess the frequency of physical activity, chronotype, and disordered eating attitudes among students, and to determine whether these factors are associated with effective functioning in academic settings and subjective cognitive well-being. A cross-sectional survey was conducted among Omani undergraduate students (n = 408) using a questionnaire covering sociodemographic characteristics and instruments, including the International Physical Activity Questionnaire, the Morningness–Eveningness Chronotype Scale, the Eating Attitudes Test, and a measure of subjective cognitive well-being. Participants’ mean age was 20.21  years (female = 74.3%). In total, 28.4% showed disordered eating attitudes, and half were physically active. 34.1% were classified as evening type. Independent regression analysis showed that chronotype was positively associated with physical activity (β = 0.06, p = 0.004). Disordered eating behavior did not significantly associate with physical activity (β = 0.1, p = 0.16). Moreover, physical activity was positively associated with cognitive function (β = 0.11, p = 0.039). However, the effect sizes were small, suggesting additional factors may contribute to these associations. This study is among the first to explore the influence of lifestyle factors on cognitive well-being in university students and may inform future studies and interventions targeting modifiable lifestyle behaviors to improve coping and academic functioning. Full article

Time-qualified dietary interventions, including time-restricted eating (TRE), intermittent fasting (IF), and periodic fasting-mimicking diets (FMDs), have emerged as strategies to improve metabolic health. While preclinical studies consistently demonstrate robust effects on energy metabolism, cardiometabolic function, and longevity, translation to humans remains heterogeneous. In free-living settings, most metabolic improvements observed with TRE and IF appear primarily driven by spontaneous caloric restriction rather than meal timing per se, and isocaloric randomized controlled trials generally show no additional benefits compared to standard calorie restriction. Evidence supporting circadian-specific advantages, particularly for early TRE, is promising but inconsistent and often context-dependent. Important uncertainties also persist regarding long-term efficacy, lean mass preservation, safety in specific populations, and the physiological impact of extended fasting windows. Despite these controversies, time-qualified diets represent a paradigm shift in nutritional science by integrating chronobiology with dietary patterns. Future directions include tailoring eating windows to individual chronotypes, combining fasting regimens with high-quality dietary patterns and structured physical activity, and clarifying the molecular mechanisms that may mediate calorie-independent benefits. Large, long-term, mechanistically informed human trials are essential to determine whether aligning eating behaviors with circadian biology can produce durable clinical improvements. Such work will ultimately shape the role of personalized chrononutrition in preventive and therapeutic nutrition. Full article

This conceptual narrative review explores the intricate dynamics of the ‘stimulant paradox’ in adult ADHD, highlighting the timing-dependent trade-offs associated with stimulant medication. The paradox underscores the complexity of balancing therapeutic benefits against potential side effects, contingent on the timing of administration. Chronopharmacotherapy emerges as a promising framework, integrating circadian and homeostatic processes with pharmacokinetic and pharmacodynamic considerations. This approach suggests that aligning medication timing with individual biological rhythms may optimize outcomes, although the conceptual nature of this integration remains non-prescriptive. ADHD coaching is examined as a complementary strategy, focusing on the development of skill-oriented routines that are sensitive to timing. This adjunctive support may facilitate the practical implementation of chronopharmacotherapy principles, enhancing adherence and effectiveness. Figures and heuristics within the review serve as illustrative tools intended to guide understanding rather than dictate clinical practice. The review identifies critical areas for future research, emphasizing the need for empirical investigation into optimal clock-time windows, phase measures, and chronotype stratification. Additionally, assumptions regarding medication formulations warrant further scrutiny to refine timing-sensitive interventions in adult ADHD management. Full article

The circadian phase difference between morning and evening types is a fundamental aspect of chronotype. However, results of categorizations into chronotypes based on reported sleep times show low concordance with those based on measurements of the hormonal or physiological or molecular rhythm–markers of the circadian phase. This might be partially explained by the profound individual differences in the phase angle between the sleep–wake cycle and these rhythms that depends on chronotype, age, sex, and other factors. Here, we examined the possibility of using self-reported sleep times in the condition of 5-days-on/2-days-off school/work schedule to estimate circadian phase differences between various chronotypes. In an in silico study, we determined that, for such an estimation, similarities of the compared chronotypes in weekend sleep duration and weekend–weekday gap and in risetime are required. In the following empirical and simulation studies of sleep times reported by 4940 survey participants, we provided examples of the estimation of circadian differences between chronotypes, and the model-based simulations of sleep times in morning and evening types exemplified a way to confirm such estimations. The results of in silico, empirical, and simulation studies underscore the possibility of using bedtimes and risetimes for direct estimation of the circadian phase differences between individuals in real-life situations, such as a 5-days-on/2-days-off school/work schedule. Additionally, the results of these studies on different chronotypes provided further mathematical modeling and empirical evidence for our failure to sleep more on weekends to recover/compensate/pay back/ catch up on lost sleep. Full article

Background/Objectives: Shift work and chronotype influence timing and type of food consumed, yet their combined influence is unclear. This study determined differences between temporal patterns of eating (times of first (FEO), last (LEO), and largest eating occasions (LarEO), duration of eating window (DEW), eating frequency) and nutrient intake of night shift workers on and off shift and the additional influence of chronotype. Methods: Participants (46.6 ± 10.2 years, BMI: 33.9 ± 5.6 kg/m², male/female: 57/72) completed work/sleep/food diaries, and the Composite Scale of Morningness. Dietary profiles were characterized by day type as follows: morning shift (MS), 1st night shift (1stNS), subsequent night shifts (SNS), 1st day off after night shifts (1stDONS), or other days off (DO). Results: Across day types, there were significant differences in FEO (p < 0.001), LEO (p < 0.001), LarEO (p = 0.025), DEW (p < 0.001), eating frequency (p = 0.003), total energy (p = 0.022), and fibre intake (p < 0.001). Compared to MS, all night shifts had later FEO, LEO, and LarEO; 1stNS had longer DEW and higher fibre but no differences in frequency, energy, and macronutrient intake. Greater morningness was associated with earlier FEO, LEO, LarEO, and lower %energy from fat and saturated fat. Effect of chronotype on temporal eating patterns was not different across day types; there was a significant, positive relationship between morningness and %energy from carbohydrate (%Energy_CHO) on MS (p = 0.004) and 1stDONS (p = 0.040). Conclusions: Dietary habits of night shift workers vary by shift schedule and degree of morningness. Further studies will confirm if shift schedule is more influential than chronotype on shift workers’ dietary habits. Full article

Background: Chronotype refers to an individual’s preferred timing of activity and rest within a 24-h period, reflecting behavioral manifestations of the endogenous circadian rhythm. Variations in circadian timing may contribute to the temporal characteristics and pathophysiology of tension-type headache (TTH). TTH is the most common primary headache disorder and can have a significant impact on quality of life. While chronotype has been shown to influence pain perception, mood, and sleep quality in various chronic pain conditions, its relationship to TTH remains insufficiently explored. Aim: We aimed to determine the distribution of chronotypes among patients with TTH and to assess their associations with pain characteristics, depression, sleep quality, and quality of life. Methods: This cross-sectional study involved 77 adult patients diagnosed with TTH according to the International Classification of Headache Disorders (ICHD)-III criteria. Patients were recruited from the neurology outpatient clinic at SANKO University Hospital between June 2021 and June 2022. Data were collected using the Morningness–Eveningness Questionnaire (MEQ), the Visual Analogue Scale (VAS), the Hospital Anxiety and Depression Scale (HADS), the Pittsburgh Sleep Quality Index (PSQI), and the Short Form-36 (SF-36). Chronotypes were categorized as morning, intermediate, or evening. Group differences were analyzed using ANOVA, Kruskal–Wallis and linear regression models. Results: The mean age of the study sample was 29.0 [24.0–35.0] years. Fifty-five participants (71.4%) had an intermediate chronotype, 14 (18.2%) had a morning chronotype, and 8 (10.4%) had an evening chronotype. Those with an evening chronotype had a significantly lower BMI than those with an intermediate chronotype (p = 0.035) and lower scores on the SF-36 Role Limitations due to Physical Problems domain than those with a morning chronotype (p = 0.039). Chronotype (as assessed by the MEQ) was negatively correlated with sleep quality, with evening chronotypes showing poorer PSQI scores. No significant differences were found in VAS (pain intensity) and HADS (depression) scores among chronotypes. Linear regression analyses indicated that chronotype significantly predicted SF-36 Bodily Pain scores, whereas sex significantly predicted VAS pain intensity (p = 0.001). Conclusions: Evening chronotype is associated with poorer sleep quality and greater role limitations due to physical problemsin patients with TTH, which can potentially exacerbate the disabilities associated with headaches. Tailored interventions targeting chronotype and sleep may improve quality of life in this population. Full article

Background/Objectives: Discrepancies in mealtimes between weekdays and weekends—often referred to as “eating jetlag”—have been linked to a higher body mass index (BMI). However, in modern societies characterized by diverse work patterns, misalignment between mealtimes and the internal circadian rhythm may result not only from weekday–weekend differences but also from day-to-day variability. The aim of this study was to quantitatively assess and visualize daily mealtime variability over a 1-month period using food log data and to investigate the association between breakfast time irregularity and BMI. Methods: We conducted a retrospective, cross-sectional analysis using food log data (n = 1072; 742 women and 360 men) extracted from a popular Japanese food-logging mobile application. Mealtime irregularity was quantified using composite phase deviation (CPD). Data were stratified by sex and age tertile. Results: Approximately 18% of participants (women and men) exhibited irregular breakfast timing (CPD > 1 h). Multivariate regression analysis revealed that an evening-type chronotype was primarily associated with BMI among younger women, whereas breakfast time irregularity was associated with BMI among older women. Conclusions: Our findings suggest that daily mealtime variability is an additional chrono-nutritional factor associated with BMI. Furthermore, the chrono-nutritional factors most strongly associated with BMI may differ by age. Full article

Undergraduate students and healthcare professionals often experience irregular sleep patterns, social jet lag (SJL), and rotating shifts that affect their performance. This study examined the association between SJL, sleep duration, and psychosocial factors among 1409 Colombian undergraduate students (mean age 24.4 ± 6.7 years) using data from the Ultra-Short Version of the Munich ChronoType Questionnaire collected between June and September 2023. Multivariable linear regression analysis identified factors associated with SJL. The prevalence of SJL exceeding two hours was high (84.6%), with an average magnitude of 4.4 h. Chronotype (MSFsc) was negatively correlated with SJL, indicating that students with later chronotypes tended to experience greater misalignment between biological and social time. Younger age and a higher number of working days were significantly associated with increased SJL, whereas substance use and mental health history showed no significant effects. These findings highlight that work-related demands, particularly frequent working days, play a key role in exacerbating social jet lag. The results underscore the need for institutional strategies to promote sleep health among Colombian university students and health professionals. Full article

Shift workers face a heightened risk of insomnia. Recent research has yielded promising insights, but further progress is necessary to better treat insomnia in this group. The present pilot study evaluates how different characteristics impact sleep in shift workers to develop an innovative therapeutic approach. An online survey was administered to an ad hoc sample of N = 225 (112 shift workers), and correlations were calculated between sleep variables and specific characteristics (e.g., psychological impairment, personality traits, sleep-related behavior, attitudes towards sleep and shift work). Group differences between good/poor sleepers and day/shift work were determined using Mann–Whitney U-tests and Kruskal–Wallis H-tests. Regression was used to identify appropriate predictors. All factors (except perfectionism, chronotype, and importance of sleep) yielded significant results in both correlations and group differences (good/poor sleepers). The two groups of day/shift workers showed only minor differences. Dysfunctional beliefs about sleep, pre-sleep arousal, and depression were identified as predictors of poorer sleep. We conclude that interventions on psychological constraints (anxiety and depression), personality traits (anxiety, concern, emotional instability, and tension), social integration, sleep-related factors (dysfunctional beliefs, especially cognitive pre-sleep-arousal, sleep hygiene) and the attitude toward shiftwork, can replace those on regularity and will build an innovative therapy for shift workers on this basis. Once the newly developed treatment manual is finalized, its efficacy will be assessed through a randomized controlled trial. Full article

Background/Objectives: The global aging population faces rising rates of cognitive decline and neurodegenerative disorders. This review explores how physical exercise influences brain health in aging, focusing on mechanisms, moderators, and personalized strategies to enhance cognitive resilience. Methods: A narrative review methodology was applied. Literature published between 2015 and 2025 was retrieved from PubMed, Scopus, and Web of Science using keywords and MeSH terms related to exercise, cognition, neuroplasticity, aging, and dementia. Inclusion criteria targeted peer-reviewed original studies in humans aged ≥60 years or aged animal models, examining exercise-induced cognitive or neurobiological outcomes. Results: Evidence shows that regular physical activity improves executive function, memory, and processing speed in older adults, including those with mild impairment or genetic risk (e.g., APOE ε4). Exercise promotes neuroplasticity through increased levels of BDNF, IGF-1, and irisin, and enhances brain structure and functional connectivity. It also improves glymphatic clearance and modulates inflammation and circadian rhythms. Myokines act as messengers between muscle and brain, mediating many of these effects. Cognitive benefits vary with exercise type, intensity, and individual factors such as age, sex, chronotype, and baseline fitness. Combined interventions—physical, cognitive, nutritional—show synergistic outcomes. Digital tools (e.g., tele-exercise, gamification) offer scalable ways to sustain engagement and cognitive function. Conclusions: Physical exercise is a key non-pharmacological strategy to support cognitive health in aging. It acts through diverse systemic, molecular, and neurofunctional pathways. Tailored exercise programs, informed by individual profiles and emerging technologies, hold promise for delaying or preventing cognitive decline. Full article

Neuronal membrane capacitance (Cm) has traditionally been viewed as a static biophysical property determined solely by the geometric and dielectric characteristics of the lipid bilayer. Recent discoveries have fundamentally challenged this perspective, revealing that Cm exhibits robust circadian oscillations that profoundly influence neural computation and behavior. These rhythmic fluctuations in membrane capacitance are orchestrated by intrinsic cellular clocks through coordinated regulation of molecular processes including transcriptional control of membrane proteins, lipid metabolism, ion channel trafficking, and glial-mediated extracellular matrix remodeling. The dynamic modulation of Cm directly impacts the membrane time constant (τm = RmCm), thereby altering synaptic integration windows, action potential dynamics, and network synchronization across the 24 h cycle. At the computational level, circadian Cm oscillations enable neurons to shift between temporal summation and coincidence detection modes, optimizing information processing according to behavioral demands throughout the day–night cycle. These biophysical rhythms influence critical aspects of cognition including memory consolidation, attention, working memory, and sensory processing. Disruptions in normal Cm rhythmicity are increasingly implicated in neuropsychiatric and neurodegenerative disorders, including depression, schizophrenia, Alzheimer’s disease, and epilepsy, where altered membrane dynamics compromise neural circuit stability and information transfer. The integration of circadian biophysics with chronomedicine offers promising therapeutic avenues, including chronotherapeutic strategies that target membrane properties, personalized interventions based on individual chronotypes, and environmental modifications that restore healthy biophysical rhythms. This review synthesizes evidence from molecular chronobiology, cellular electrophysiology, and systems neuroscience to establish circadian Cm regulation as a fundamental mechanism linking molecular timekeeping to neural computation and behavior. Full article