Chronobiology International最新文献

{"title":"Reliability and validity of a smartwatch with a photoplethysmograph: Comparison with a Holter electrocardiograph.","authors":"Chieko Tan, Tomoya Tamei, Atsue Ishii, Nobue Arimoto, Hideyuki Shiotani","doi":"10.1080/07420528.2026.2669593","DOIUrl":"https://doi.org/10.1080/07420528.2026.2669593","url":null,"abstract":"<p><p>Although consumer-grade smartwatches with a photoplethysmograph (PPG) can measure heart rate, their reliability and validity in healthy participants under free-living conditions remain unclear. Therefore, this study compared the heart rates measured by a smartwatch with PPG and a clinically accepted Holter electrocardiograph in healthy adult participants under completely free-living conditions. Ten participants wore a Holter recorder on their left chest and a Garmin vivosmart 5 on their non-dominant wrist simultaneously for 72-96 h. Averages were calculated every 2 min from the data obtained, and timestamps were used for alignment. Agreement between the measurements taken by the two devices was verified using intraclass correlation and Bland-Altman analyses. Error trends for Garmin vivosmart 5 were examined using linear regression analysis. The overall intraclass correlation coefficient range was 0.819-0.937 (mean: 0.902), indicating strong agreement. The mean bias was 1.16 bpm, and the mean limit of agreement was ±12.4 (7.87-20.6) bpm. Furthermore, the linear regression line intercept was negative for all participants, indicating that Garmin vivosmart 5 tended to underestimate the heart rate; however, the slope was positive and close to 0. Overall, the smartwatch maintained a certain accuracy level under fluctuating heart rates and demonstrated reasonable reliability during sleep or daily activities.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-9"},"PeriodicalIF":1.7,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147834069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mediating effect of sleep hygiene between morningness-eveningness preferences and psychological distress among a sample of Lebanese adults.","authors":"Nada Akiki, Souheil Hallit, Diana Malaeb, Fouad Sakr, Mariam Dabbous, Sahar Obeid, Feten Fekih-Romdhane, Rabih Hallit","doi":"10.1080/07420528.2026.2670688","DOIUrl":"https://doi.org/10.1080/07420528.2026.2670688","url":null,"abstract":"<p><p>Our study explored the mediating effect of sleep hygiene between morningness-eveningness preferences and psychological distress among a sample of Lebanese adults. A total of 948 Lebanese participants were enrolled in this cross-sectional study (mean age 26.93 ± 10.23 years). A self-administered survey was dispersed using the snowball sampling technique. The survey consisted of socio-demographic characteristics along with the following Arabic validated instruments: The Morningness-Eveningness Questionnaire (MEQ), the Patient-Health Questionnaire (PHQ-4), and the Sleep Hygiene Index (SHI). Statistical analysis was performed using SPSS v.27 with mediation analysis via PROCESS MACRO v.42 Model 4. Sleep hygiene fully mediated the relationship between morningness-eveningness preferences and psychological distress. Greater morningness preferences were significantly associated with better sleep hygiene (i.e. lower sleep hygiene scores). In turn, poor sleep hygiene (i.e. higher sleep hygiene scores) was significantly associated with higher psychological distress. The direct association between morningness and psychological distress was not statistically significant. Our study offered insight on important connections between sleep hygiene, morningness-eveningness preferences, and psychological distress within the Lebanese context. These results highlight the necessity of promoting healthy sleep behaviors and chronobiological awareness to improve mental health in this population.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-10"},"PeriodicalIF":1.7,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147834051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronotype and health outcomes in shift-working healthcare professionals: Associations with eating attitudes, depressive symptoms, and quality of life.","authors":"Gökçe Kavak Sinanoğlu, Mustafa Sinanoğlu","doi":"10.1080/07420528.2026.2670681","DOIUrl":"https://doi.org/10.1080/07420528.2026.2670681","url":null,"abstract":"<p><p>Shift work is an essential component of healthcare systems but induces chronic circadian misalignment through disruption of the sleep - wake cycle, nocturnal light exposure, and desynchronization between endogenous biological rhythms and environmental time cues. Such misalignment has been associated with adverse physical and psychological health outcomes. Chronotype, reflecting intrinsic circadian phase preference, has been proposed as a potential modifier of individual responses to shift work; however, its role among shift-working healthcare professionals remains incompletely understood. This cross-sectional study investigated the associations between chronotype and health-related quality of life, depressive symptoms, and eating attitudes among 278 healthcare professionals engaged in rotating shift schedules. Chronotype was assessed using the Morningness - Eveningness Questionnaire and categorized as morning, intermediate, or evening type. Physical and mental health - related quality of life were evaluated using the SF-36, yielding Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. Depressive symptoms and eating attitudes were assessed using validated questionnaires. Group differences were examined using non-parametric tests, and multivariable analyses were performed to adjust for sociodemographic variables and explore non-linear effects. Significant differences in physical health - related quality of life were observed across chronotype groups. Evening-type participants demonstrated lower PCS scores compared with morning and intermediate types (<i>p</i> < 0.05), particularly in the Role Physical (RP) domain. However, in multivariable regression analyses, chronotype was not a significant independent predictor of PCS, whereas age and marital status remained significant. No significant differences were observed between chronotype groups in depressive symptoms, eating attitudes, or MCS scores (all <i>p</i> > 0.05). In conclusion, chronotype may be associated with differences in physical health - related quality of life among shift-working healthcare professionals; however, these associations appear to be influenced by sociodemographic and contextual factors rather than representing a direct relationship. These findings underscore the complexity of circadian adaptation in shift work and highlight the need for further longitudinal research.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-8"},"PeriodicalIF":1.7,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlates of weekday sleep duration before and during the COVID-19 lockdown: Evidence from two Austrian national surveys from 2017 and 2020.","authors":"Jürgen Degenfellner, Stefan Seidel, Kyriaki Papantoniou, Eva Schernhammer, Susanne Strohmaier","doi":"10.1080/07420528.2026.2659919","DOIUrl":"https://doi.org/10.1080/07420528.2026.2659919","url":null,"abstract":"<p><p>The COVID-19 pandemic profoundly disrupted daily life, including sleep behaviour. While several international studies report longer sleep durations during lockdown, most relied on convenience samples and only few influencing factors were considered. The aim of this study was to identify correlates of weekday sleep duration before and during Austria's first lockdown using two population-based cross-sectional surveys. Data were drawn from online surveys in September 2017 (<i>n</i> = 784) and May 2020 (<i>n</i> = 847), weighted to match the Austrian adult population by age and sex. Weekday sleep duration was derived from self-reported bed and wake times. Weighted linear regression models were fitted using backward elimination to select among known and suspected correlates of sleep duration. In 2020, additional COVID-specific covariables were considered. Covariable selection stability was assessed via bootstrapping. Compared to 2017, sleep duration increased in 2020 by 40 min (95% CI 27-55). Several covariables (minimum required sleep, work schedule, dinner time, chronotype, and diagnosed sleep disorder, education level and smoking status) were consistently retained in the selection models in both survey years. In 2020, COVID-specific factors such as changes in sleep quality, emotional burden during lockdown, and attitude toward the future further explained variation in sleep duration. Inclusion of these variables increased the adjusted model fit (R²) from 0.26 to 0.31. Beyond established determinants, COVID-related factors contributed substantially to explain variation in sleep duration during the lockdown. Our findings underscore the importance of incorporating context-specific covariables in future surveys to capture behavioural adaptations, e.g. during societal crises.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-12"},"PeriodicalIF":1.7,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dietary inflammatory and phytochemical indices as predictors of sleep quality, chronotype, and psychological health in adults.","authors":"Elif Ulug, Nesli Ersoy, Aylin Acikgoz Pinar","doi":"10.1080/07420528.2026.2669597","DOIUrl":"https://doi.org/10.1080/07420528.2026.2669597","url":null,"abstract":"<p><p>The dietary pattern might impact physiological and psychological health. Therefore, the present study aims to examine the associations of dietary phytochemical index (DPI) and dietary inflammatory index (DII) with chronotype, sleep, and psychological health in adults. This cross-sectional study included 628 healthy adults aged 19-64 y (mean age: 25.9 ± 9.7 y). Data on anthropometrics, physical activity, chronotype (Morningness-Eveningness Questionnaire (MEQ)), sleep quality (Pittsburgh Sleep Quality Index (PSQI)), and psychological status (Depression, Anxiety, and Stress Scale-21 (DASS-21)) were collected. Dietary intake was assessed using a validated semi-quantitative Food Frequency Questionnaire. The DPI was calculated using two different methods, one developed by McCarty and the other by Bahadoran et al. while the DII was computed based on the method developed by Shivappa et al. In the adjusted models, the DPI (according to McCarty) was positively associated with MEQ scores and negatively associated with PSQI and DASS-21 subscale scores, and increasing DPI was associated with significantly decreased odds of exhibiting mid- or evening chronotypes and poor sleep quality (<i>p</i> < 0.05). Although DPI (according to Bahadoran et al.) was positively associated with MEQ total score (<i>p</i> < 0.05), no significant associations were observed in the risk estimates for chronotype, sleep quality, and DASS-21 scores after adjustment (<i>p</i> > 0.05). Moreover, in the adjusted models, DII was not significantly associated with chronotype, sleep quality, or any DASS-21 sub-group (<i>p</i> > 0.05). A higher dietary phytochemical index was associated with a higher morningness tendency, better sleep quality, and lower levels of depression, anxiety, and stress. These findings underscore the potential link between an anti-inflammatory, phytochemical-rich dietary pattern, and psychological and physiological well-being.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-12"},"PeriodicalIF":1.7,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147833835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning approaches in predicting circadian rhythm sleep-wake disorders: A review.","authors":"Trina Sengupta, Archana Gaur, Sakthivadivel Varatharajan","doi":"10.1080/07420528.2026.2667404","DOIUrl":"https://doi.org/10.1080/07420528.2026.2667404","url":null,"abstract":"<p><p>Circadian rhythm sleep-wake disorders (CRSWDs) arise from misalignment between an individual's sleep-wake timing and endogenous circadian physiology, with substantial consequences for sleep health and overall well-being. In the era of sleep-omics and digital phenotyping, machine learning (ML) offers powerful tools for modelling complex, high-dimensional circadian data; however, its application to CRSWD prediction remains under developed. This systematic review aims to synthesize current evidence on the use of ML approaches for circadian phase estimation and CRSWD classification in humans. We have conducted a systematic search of PubMed, ScienceDirect, PsycINFO, Cochrane Library, and Google Scholar for studies published between January 2011 and May 2025. Eligible studies focused on sighted adults where ML algorithms predicted circadian phase or classified CRSWDs. Data sources included sleep diaries, actigraphy, genomics, and biological markers. To maintain model homogeneity and account for physiological differences, studies involving pediatric populations, neurodegenerative comorbidities, or blind individuals were excluded. A total of 22 studies met the inclusion criteria. Across studies, ML models demonstrated promise for circadian phase estimation and CRSWD classification using diverse data modalities, including wearable-derived time-series data and multimodal features. However, the evidence base remains limited by small sample sizes, methodological heterogeneity, limited external validation, and inconsistent reporting standards. Overall, current findings suggest that while ML-based approaches hold significant potential for advancing CRSWD detection and personalized circadian medicine, more robust, standardized, and generalizable models are required. Future research should prioritize larger multimodal datasets, transparent validation strategies, and clinically translatable tools to support scalable CRSWD screening and diagnosis.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-16"},"PeriodicalIF":1.7,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147834138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Associations between chrononutrition variables and hypertension in adults.","authors":"Jinrong Yang, Pucheng Mei, Hongfang Yang, Changsi Wang, Qi Nie, Lin Zhu, Wei Yang, Ping Wu, Hongfei Ma, Li Zhou","doi":"10.1080/07420528.2026.2667408","DOIUrl":"https://doi.org/10.1080/07420528.2026.2667408","url":null,"abstract":"<p><p>Associations between chrononutrition variables (time of first meal, time of last meal and eating window) and hypertension remain unclear. This study aimed to examine associations between chrononutrition variables and hypertension. In this cross-sectional study, chrononutrition variables, including time of first meal, time of last meal, and eating window, were collected via face-to-face interviews. Blood pressure was measured using a standardized protocol, and hypertension was defined as measured blood pressure ≥140/90 mmHg, self-reported physician diagnosis, or antihypertensive medication use. Logistic regression models were used to assess the associations between chrononutrition variables and hypertension. Stratified analyses were performed to examine the association between time of first meal and hypertension across subgroups. Among 1,588 adults, a later time of first meal was initially associated with a lower prevalence of hypertension, but this association was attenuated and became non-significant after adjustment for wake time and sleep time. No significant associations were observed for time of last meal or eating window. No significant association was observed between chrononutrition variables and hypertension after adjustment for wake time and sleep time.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147811945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Night owls at risk: Evening chronotype predicts job burnout under high emotional demands among firefighters.","authors":"Łukasz Baka, Łukasz Kapica, Halina Sienkiewicz-Jarosz, Joanna Bugajska, Maja Bańkowska, Karolina Neugebauer, Kamila Pietras, Piotr Świtaj","doi":"10.1080/07420528.2026.2663950","DOIUrl":"https://doi.org/10.1080/07420528.2026.2663950","url":null,"abstract":"<p><p>The present longitudinal study examined the associations between chronotype and two core components of job burnout - exhaustion and disengagement from work - among firefighters, and explored whether emotional demands moderate these relationships. The sample comprised 557 male firefighters who were assessed twice, with a six-month interval between measurements. Hypotheses were tested using a cross-lagged panel model. Results indicated that an evening chronotype predicted higher subsequent levels of both exhaustion and disengagement. In contrast, the reverse direction of effects - job burnout predicting later changes in chronotype - was not supported, suggesting that circadian preference may serve as an antecedent rather than a consequence of burnout. Furthermore, emotional demands moderated the association between chronotype and burnout. Specifically, firefighters with an evening chronotype who experienced high emotional demands were at the greatest risk of disengagement. However, this interaction effect was observed only for disengagement, not for exhaustion. These findings provide longitudinal evidence linking eveningness to an increased vulnerability to job burnout, particularly under emotionally demanding work conditions. The results underscore the importance of considering individual circadian preferences in occupational health research and suggest that interventions aimed at mitigating burnout should take into account both chronotype and the emotional context of work.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"1-13"},"PeriodicalIF":1.7,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147811972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Travel-induced circadian shift between teams influences penalties in the National Hockey League.","authors":"Vincent Bourgon, Joshua Fournier, Félix-Gabriel Duval, Geneviève Forest","doi":"10.1080/07420528.2026.2623040","DOIUrl":"10.1080/07420528.2026.2623040","url":null,"abstract":"<p><p>There is a growing recognition of the impact of circadian rhythms on athletic performance, when teams crossing multiple time zones play at a different circadian alignment than their opponents. This study aimed to examine the association between circadian differences between NHL teams and increased penalty behavior. Data from NHL games played between 2009 and 2021 (<i>n</i> = 27,642) were analysed. A travel-adjusted time zone was computed for both teams, from which a Difference in alignment between teams was calculated: Ahead, same as, and behind opponent. A one-way ANOVA was done with the Difference in alignment on the number and minutes of penalties and results were significant for both variables. Post-hoc analyses revealed that teams behind received significantly fewer penalties (<i>p</i> < 0.001) than teams ahead or in the same time zone as their opponents (<i>p</i> < 0.001) and had fewer penalty minutes than teams who were in the same time zone as their opponent (<i>p</i> = 0.002). These results suggest that teams playing at a later point in their circadian cycle than their opponents were given more penalties, which highlights the importance of professional organisations understanding the potential influence of circadian rhythms and travel on behavior and performance outcomes during games.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"676-680"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146084472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volatile anesthesia suggests functional separation of clocks underlying circadian rhythms and photoperiodic responses in a wasp.","authors":"Ayumu Mukai, Shin G Goto","doi":"10.1080/07420528.2026.2624013","DOIUrl":"10.1080/07420528.2026.2624013","url":null,"abstract":"<p><p>Photoperiodism, the ability to respond to changes in day length, enables many temperate organisms to adapt their life cycles to seasonal variations. Although much research has focused on the molecular mechanisms of the circadian clock in photoperiodism, the relationship between the clocks that govern daily behavioral rhythms and the photoperiodic response remains unclear. Here, we used the volatile anesthetic agent isoflurane to investigate this relationship in the parasitic jewel wasp, <i>Nasonia vitripennis</i>. Six hours of isoflurane administration (IA) during the first (Zeitgeber time [ZT] 0) and second halves (ZTs 6 and 8) of the photophase followed by constant conditions, induced a phase delay and a phase advance in the activity onset, respectively, while IA at these ZTs followed by dark and light cycles cancelled the IA-induced phase shifts. Interestingly, daily IA during the second half of the photophase (ZT 8) in the light-dark cycles increased the incidence of diapause. These results indicate that IA affects both locomotor activity rhythms and photoperiodic responses, but in an inconsistent manner. The present results are consistent with the possibility that the clock regulating behavioral rhythms is at least partially independent of the system controlling photoperiodic response in this species.</p>","PeriodicalId":10294,"journal":{"name":"Chronobiology International","volume":" ","pages":"694-703"},"PeriodicalIF":1.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146141183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}