Search Results (542)

Depression and osteoporosis frequently co-occur, presenting a significant and increasing clinical challenge, especially among older adults. Growing research highlights the bone–brain axis, a complex bidirectional communication network connecting the skeletal and central nervous systems, as a central mechanism linking these conditions. This review comprehensively examines the current knowledge of the molecular and cellular pathways within this axis that contribute to depression–osteoporosis interactions. It details how depression promotes bone loss through sustained hypothalamic–pituitary–adrenal axis activation, sympathetic nervous system overactivity, and chronic low-grade inflammation. This review also explores how bone-derived factors, including osteocalcin, lipocalin 2, and extracellular vesicles, cross the blood–brain barrier to influence brain function by regulating hippocampal neurogenesis, serotonin signaling, and neuroinflammation. This bidirectional communication is modulated by circadian rhythms and genetic factors. Understanding these pathways offers critical insights into the shared pathophysiology and reveals promising therapeutic targets. Interventions such as neuromodulation, customized exercise programs, and novel treatments focusing on bone-derived signals show potential for simultaneously addressing both mood disorders and bone health deterioration. This review emphasizes the need for an integrated system-based approach in clinical care that moves beyond traditional specialty-focused treatment to improve overall health outcomes, particularly for vulnerable elderly individuals. Full article

Shift workers are at elevated risk of chronic diseases due to circadian rhythm disruption, suboptimal lifestyle behaviors, and potentially altered gut microbiota (GM). This study investigated variations in GM diversity and composition across three weekly shifts in rotating shift workers and following walnut supplementation. Using a within-person design, GM diversity and composition were compared in 13 shift workers during morning, afternoon, and night shifts. After a three-week observational period, participants added a daily serving of walnuts to their habitual diet for an additional three weeks. GM was analyzed via 16S rRNA sequencing, assessing diversity and bacterial composition across shift types and between the observational and interventional phases. Overall GM composition did not differ between the beginning and end of shifts, by shift type, or following walnut supplementation. Bacterial diversity remained stable except for a significant decrease at the end of the night shift during observation (p = 0.03), which was not observed during walnut supplementation. GM clustered strongly by subject, and a healthier diet correlated with greater mean GM diversity (r = 0.64, p = 0.02). Despite overall GM stability, the decline in diversity during night shifts suggests that targeted nutritional strategies, such as walnut supplementation, may help preserve gut health in shift workers. Full article

Cardiometabolic diseases, including hypertension, type 2 diabetes, dyslipidemia, and obesity, along with their cardiovascular complications, remain leading causes of morbidity and mortality worldwide, imposing significant public health, economic, and societal burdens. Conventional pharmacological therapies often show limited efficacy and increased adverse effects because they do not account for the body’s intrinsic circadian rhythms, which regulate organ function, drug absorption, and metabolism. Chronopharmacology, which aligns treatment timing with these biological rhythms, offers a strategy to enhance therapeutic outcomes. This review presents a comprehensive analysis of chronopharmacology principles applied to cardiometabolic disease management, integrating molecular, physiological, and clinical perspectives. It examines how core clock genes and tissue-specific circadian patterns influence drug action and absorption and summarizes evidence-based time-optimized interventions for hypertension, diabetes, dyslipidemia, obesity, and multimorbid patients. Furthermore, the review highlights emerging innovations, including artificial intelligence-guided dosing, circadian-biomarker-informed therapy selection, and wearable digital devices for real-time monitoring of biological rhythms. By synthesizing mechanistic and clinical insights, circadian-aligned treatment strategies are shown to improve drug efficacy, reduce adverse effects, and support the development of precision, rhythm-based therapeutics, offering a practical framework for personalized cardiometabolic disease care. Full article

Circadian disruption (CD) has emerged as a critical factor compromising human health in contemporary society. Increasing evidence suggests that disturbances in circadian rhythms are involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer’s disease (AD). The hyperphosphorylation of tau and the deposition of amyloid-β (Aβ) are recognized as major pathological hallmarks of AD. In this study, we aimed to explore the impact of long-term CD on AD-like pathological changes and to explore the underlying molecular mechanisms using a mouse model. To mimic the CD experienced by shift workers, mice were subjected to lighting conditions involving repeated reversals of the light–dark cycle. In this study, qPCR was to employed detect the expression profile of clock genes in the hippocampus. Subsequently, Western blotting and immunohistochemical analyses were used to evaluate AD-like pathological changes in the hippocampus following CD. For elucidating the underlying mechanisms, we assessed circadian expression patterns of major neurotransmitters, activation of microglia and astrocytes, and alterations of tight junction proteins within the hippocampus. Our findings demonstrated that light–dark cycle disruption triggered CD in mice, and then CD led to increased expression of Aβ protein and tau hyperphosphorylation. CD significantly disrupted the circadian expression profiles of hippocampal clock genes and major neurotransmitters, induced microglial and astrocytic activation, and decreased the expression of the tight junction proteins zonula occludens-1 and occludin in the hippocampus. These results suggest that changes in the light–dark cycles induced abnormal expression of hippocampal clock genes involved in circadian rhythm regulation, suggesting that the body is in a state of endogenous CD. CD induces AD-like pathological changes in mice, potentially mediated by dysregulated circadian oscillations of clock genes, neuroinflammation, loss of key blood–brain barrier proteins, and disturbed neurotransmitter expression in the hippocampus. Collectively, this study underscores the importance of circadian stability for brain health, and highlights the necessity for deeper exploration into the connection between AD and CD. Full article

Sleep plays a central role in shaping emotional development during childhood and adolescence, yet increasing evidence indicates that these processes unfold differently in boys and girls. This narrative review synthesizes current findings on sex-specific associations between sleep patterns, neurodevelopmental trajectories, and emotional regulation across pediatric populations. It examines how biological factors, including pubertal timing, sex hormones, circadian physiology, and maturation of fronto-limbic circuits, interact with environmental influences to generate distinct vulnerabilities to anxiety, depression, and behavioral dysregulation. Growing data suggest that girls exhibit greater sensitivity to sleep disturbances, particularly during the pubertal transition, with stronger links to internalizing symptoms such as anxiety and mood disorders. In contrast, boys appear more prone to externalizing behaviors and show differential responses to circadian misalignment and short sleep duration. Emerging evidence on sex-specific sleep architecture, REM-related emotional processing, and the bidirectional pathways through which sleep quality affects affective functioning are explored. Finally, clinical implications for early detection, personalized prevention, and targeted interventions tailored by sex and developmental stage are discussed. Understanding sex-based differences in sleep–emotion interactions offers a critical opportunity to refine pediatric mental health strategies and improve outcomes across developmental trajectories. Full article

Background/Objectives: Sensory deprivation, defined as a reduction or absence of external sensory input across one or more modalities, has long been investigated in extreme and experimental settings. More recently, its relevance has expanded to clinical contexts and environmental conditions. The present narrative review aims to synthesize current evidence on the neurobiological mechanisms, psychological effects, and clinical implications of sensory deprivation, with particular attention to its dual role as both a risk factor and, under controlled conditions, a potential therapeutic tool. Methods: A narrative literature search was conducted using PubMed, Scopus, and PsycINFO, covering studies published up to August 2025. Search terms included sensory deprivation, neuroplasticity, neurotransmitters, HPA axis, neuro-inflammation, circadian rhythms, psychopathology, extreme environments, and spaceflight. Preclinical and clinical studies examining biological, cognitive, and psychological consequences of reduced sensory stimulation were included. Data were synthesized thematically without quantitative meta-analysis. Results: Evidence indicates that sensory deprivation induces widespread neurobiological adaptations involving neurotransmitter systems (particularly dopaminergic pathways), dysregulation of the hypothalamic–pituitary–adrenal axis, neuroimmune activation, circadian rhythm disruption, and structural and functional brain changes, notably affecting the hippocampus. These alterations are associated with increased vulnerability to depression, anxiety, hallucinations, dissociative symptoms, and cognitive impairment. Duration, voluntariness, and individual differences (e.g., baseline vulnerability/resilience, trait anxiety, and prior psychiatric history) critically modulate outcomes. However, short-term and voluntary sensory restriction, such as Floatation-REST, may promote relaxation and emotional regulation under specific conditions. Conclusions: Sensory deprivation exerts complex, context-dependent effects on brain function and mental health. Duration, individual vulnerability, and voluntariness critically modulate outcomes. Understanding these mechanisms is increasingly relevant for clinical practice and for developing preventive strategies in extreme environments, including future long-duration space missions. Full article

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

Background: Rotating and night-including shifts disrupt circadian alignment, impair sleep, and may reduce nurses’ physiological recovery. Objectives: This study aimed (1) to compare sleep quality and physical well-being across four shift schedules among hospital nurses and (2) to examine whether the association between rotating shifts and physical well-being was statistically consistent with an indirect association via sleep quality. Methods: In this cross-sectional study, 173 nurses from a tertiary hospital in Zagreb, Croatia, completed validated measures of sleep quality and physical well-being. Four shift patterns were analyzed—fixed morning, morning–afternoon, extended 12-h, and rotating three-shift—using Welch ANOVA and regression models. A bootstrapped mediation analysis (10,000 resamples; BCa method), interpreted as a statistical decomposition, estimated an indirect association consistent with sleep quality. Results: Rotating-shift nurses reported the poorest sleep (PSQI = 10.2 ± 2.6; p = 0.003). Physical well-being did not differ significantly across shift types (p = 0.08), although rotating-shift nurses had the lowest mean physical scores (24.3 ± 4.4). The rotating-shift subgroup was small (n = 16), limiting precision. The mediation analysis was statistically consistent with an indirect association between rotating shifts and physical well-being via sleep quality (ACME = −1.85, 95% CI −3.05 to −0.88; p < 0.001), while the proportion of the total association was imprecisely estimated. Conclusions: In this single-site cross-sectional sample, rotating night shifts were associated with poorer sleep and, on average, lower physical well-being; patterns were statistically consistent with an indirect association via sleep quality. Because exposure, mediator, and outcome were measured concurrently, these findings are hypothesis-generating and do not establish causality. 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

Background. Exposure to artificial light at night can lead to circadian disruption and health risks. It can cause mood swings, confusion, and depression. The aim of this cross-sectional study was to assess the relationship between the illuminance of urban lighting and the health of residents. Methods: This study was carried out among residents of two similar towns, one with typical street lighting and a Dark Sky Park characterized by reduced lighting. A total of 272 respondents participated in this study. A self-administered questionnaire and the WHOQOL-BREF were used among the respondents. Results. People living in the Dark Sky Park were more likely to be satisfied with their sleep (p < 0.001). In fact, 58.7% of Dark Sky Park residents reported no sleep problems. In the control town, only 49.25% did (p = 0.04). The sleep duration was similar in the two towns, but Dark Sky Park residents were statistically less likely to use sleeping pills and window blinds. People exposed to typical street lighting at night reported suffering from eye diseases, cardiovascular diseases, and mood changes more often than those living in the Dark Sky Park. The environmental and physical quality of life, as measured by the WHOQOL-BREF, were significantly higher in the Dark Sky Park residents than in the control town (p < 0.05). Conclusions. People living in places with limited illuminance declare better health and a higher quality of life in the physical and environmental domains. Full article

Background: Obesity and its accompanying complications have an influence on diurnal rhythm, potentially causing cardiometabolic disease. This study explores how weight loss due to bariatric surgery affects circadian rhythm disruptions measurable through wearable heart rate monitors. Methods: A single-center observational study was performed, in which patients who had undergone primary bariatric surgery 3 years ago with telemonitoring of vital parameters using a wireless accelerometer were eligible to participate. A Wilcoxon signed-rank test was conducted to evaluate the delta of, or amount of change in, circadian patterns between the baseline (before) and post-weight-loss peak, nadir, and peak–nadir heart rates. Results: In this cohort of 69 patients, 70% were female, with a median total weight loss of 31.4% towards a median BMI of 28.4 kg/m². Analysis revealed significant changes in peak–nadir excursions post-weight loss. Peak, nadir, and peak–nadir differences showed a significant reduction in values in the post-weight-loss group. No significant correlations between other clinical endpoints and change in peak–nadir excursion were found in the multivariable regression models. Conclusions: In conclusion, this study reveals significant changes in circadian heart rate patterns before and after weight loss due to metabolic surgery. The results could add to the health benefits of bariatric surgery, as it could lower the incidence of diseases associated with changes in diurnal rhythm due to obesity. However, a clear clinical explanation is lacking, as no correlation with total weight loss nor other variables was substantiated. Full article

Research indicates that TRF improves mammalian metabolism and health via the microbiota–gut–brain axis. Previous studies showed that TRF promotes pig growth, but the intestinal mechanisms remain unclear. This study explored the impact of TRF on pig intestinal functions. Twelve male pigs were split into ad libitum feeding (FA) and TRF groups. FA pigs had free access to feed, whereas TRF pigs were fed during 07:00–08:00, 12:00–13:00, and 17:00–18:00. TRF enhanced crude protein digestibility by 18.9% (p = 0.045) and increased pancreatic chymotrypsin and lipase activities, while reducing ileal amylase, sucrase, and lipase activities. Transcriptomic analysis identified 1339 differentially expressed genes (DEGs) in the jejunum and 268 in the colon, indicating segment-specific responses. Jejunal DEGs were associated with protein digestion and absorption (e.g., SLC1A1, SLC38A2, XPNPEP2), extracellular matrix–receptor interaction, and PI3K-Akt signaling, while colonic DEGs were linked to starch and sucrose metabolism and circadian entrainment. Importantly, TRF decreased colonic starch by 24% (p = 0.02) and cellulose by 18% (p = 0.04), with low impact on nitrogenous substrates. These results suggest that TRF improves protein absorption in the upper intestine and carbohydrate metabolism in the lower intestine, providing insights for refining TRF strategies in precision nutrition. Full article

Late-night feeding, defined in the present review as feeding after 8:00 pm when evening insulin secretion and sensitivity are low, is increasingly prevalent in Western society and is recognized as a disruptor of metabolic homeostasis. Yet health problems related to late-night feeding are largely ignored in time-restricted feeding studies that generally do not extend past an 8:00 pm feeding window. This paper proposes a novel cascade linking late-night hyperglycemia with sleep disturbances and nasal congestion mediated by renal sodium retention, increased plasma osmolarity, and stress hormone release by hypothalamic–pituitary–adrenal axis activation. The narrative describes the circadian decline in insulin sensitivity, which amplifies postprandial glucose surges following late-night feeding. Elevated glucose levels drive renal glucose reabsorption via sodium–glucose cotransporters, promoting sodium retention independent of insulin. Increased sodium retention raises extracellular osmolarity, activating hypothalamic osmoreceptors and stimulating the hypothalamic–pituitary–adrenal axis. Cortisol release promotes alertness, while fluid retention and mucosal edema contribute to nasal congestion and early waking. Supine fluid redistribution during sleep further exacerbates airway narrowing, increasing the risk of sleep fragmentation and obstructive sleep apnea. The present paper fills a gap in current time-restricted feeding literature by integrating renal, osmotic, and neuroendocrine pathways that may be overlooked as underlying mechanisms of dysregulated glucose control and hormone dysfunction. Reviewed evidence suggests that symptoms such as nocturnal congestion and sleep disruption are not merely incidental to late-night feeding but frame late night feeding as a risk factor with underlying physiological stressors that could contribute to cardiometabolic risk. Full article

Emergency Departments (EDs) are high-pressure environments that place significant psychological and physiological stress on both patients and healthcare staff. Despite increasing awareness of stress-related impacts, proactive stress management interventions have limited uptake in healthcare. This proof-of-concept study will evaluate WeCare: a 6-week, wearable-integrated, self-guided program grounded in a “Learn–Track–Act” framework to support stress regulation, resilience, and wellbeing. The study will examine four key aspects of implementing the program: (1) feasibility, (2) acceptability and usability, (3) preliminary clinical effectiveness (self-report and physiological outcomes), and (4) preliminary economic impacts. Using a mixed-methods, multiple-baseline N-of-1 design, the program will be trialled with up to 32 participants across four ED-exposed groups: patients with non-severe or severe injuries, patients with acute medical presentations, and ED staff. The intervention includes digital psychoeducation, continuous biofeedback via a smart ring, personalised guidance, and evidence-based self-regulation strategies. Assessments will include standardised questionnaires combined with continuous physiological monitoring via a smartwatch, and interviews. Quantitative outcomes include heart rate variability, sleep patterns, perceived stress, wellbeing, healthcare use, and time off work. Qualitative interviews will explore user experience, usability, and perceived barriers. The findings will inform the refinement of the intervention and co-design of a larger-scale trial, contributing valuable evidence to support low-cost, wearable-enabled proactive mental healthcare in high-stress healthcare environments. Full article