npj Biological Timing and Sleep最新文献

{"title":"Impact of wear position on dosimeter performance: a hybrid measurement-simulation approach to quantify in-situ factors.","authors":"S W de Vries, J Mardaljevic, J van Duijnhoven","doi":"10.1038/s44323-026-00079-z","DOIUrl":"10.1038/s44323-026-00079-z","url":null,"abstract":"<p><p>Quantifications of personal light exposure (PLE) are important for research on human health and well-being. To capture real-world PLE, dosimeters (light sensors) are often worn on the body, rather than at the eye. Currently, it is largely unknown how such placement influences the dosimeter's performance for measuring actual eye-level light exposure. To overcome limitations of real-world studies, we introduce a novel hybrid measurement-simulation approach to quantify three factors affecting dosimeter performance: the translational and rotational dosimeter displacement and body self occlusion. Using 3D body scans of twelve subjects, we illustrate how an individual's body morphology influences the magnitude and distribution of these factors and identify the dosimeter positions where these factors are minimized. Additionally, we defined illustrative limits to identify regions of the chest suitable for dosimeter placement. Depending on the subject's posture, between 0 and 46.4% of the chest area exhibits sufficiently small magnitudes of these factors to be considered suitable. To ensure valid PLE data in light-dosimetry field studies, it is essential to select a dosimeter position that minimizes each of these three factors for typical subject postures.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144307/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147848454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of wear position on dosimeter performance: measurement validity under simulated indoor illumination.","authors":"S W de Vries, J Mardaljevic, J van Duijnhoven","doi":"10.1038/s44323-026-00073-5","DOIUrl":"10.1038/s44323-026-00073-5","url":null,"abstract":"<p><p>The light an individual is exposed to, or personal light exposure (PLE), plays an important role in human health and well-being research. PLE is typically quantified using body-worn light dosimeters (sensors), but their effectiveness as a proxy for measuring at the eye remains insufficiently understood. By combining 3D body scans and lighting simulations, we quantified the discrepancies between chest-worn and eye-level dosimeter measurements under three generalized indoor lighting scenarios. Chest-worn dosimeter performance was found to be highly context-dependent, with the smallest deviations (between -26.2% and 63.8%) observed for devices on the lower chest. Quantifying corneal light exposure, i.e., considering the field of view of the human eye, based on chest-worn dosimeter measurements proved problematic as deviations under overhead lighting exceeded a minimum 25%. To deepen our understanding of the underlying mechanisms, we disaggregated the causes of these discrepancies into three factors: the translational dosimeter displacement, the rotational dosimeter displacement, and body self-occlusion. The results indicate that minimizing the rotational displacement is key to reducing measurement discrepancies and inter-individual variability. To improve the validity of chest-worn dosimetry, an individualized approach is recommended: selecting a chest position where the dosimeter best aligns with the subject's typical view direction during expected activities.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144681/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147848534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Translational applications of circadian research: connecting chronobiology to medicine.","authors":"Elizabeth B Klerman","doi":"10.1038/s44323-026-00084-2","DOIUrl":"10.1038/s44323-026-00084-2","url":null,"abstract":"<p><p>Chronobiology has advanced scientifically since 2000. Translating this knowledge and approach to medicine can alter diagnosis, treatment, and prevention, and improve health. Adding time-of-day (or time-of-year) information is both a concrete and conceptual change to clinical practice and public health relevant to humans and other animals, with low implementation costs. Successful translation of chronobiology to medicine requires new methods, training, and organizational and regulatory action.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13135512/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147825551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fecal melatonin as a biomarker of emerging circadian maturity and gut microbiota in infancy.","authors":"Mohammed Al-Andoli, Petra Zimmermann, Sarah Schoch, Andjela Markovic, Christophe Mühlematter, Matthieu Beaugrand, Oskar G Jenni, Rabia Liamlahi, Jean-Claude Walser, Dennis Nielsen, Salome Kurth","doi":"10.1038/s44323-026-00080-6","DOIUrl":"10.1038/s44323-026-00080-6","url":null,"abstract":"<p><p>Melatonin plays a key role in circadian regulation, and its interaction with the gut microbiota may be critical for early-life development. Beyond its circadian function, melatonin dysregulation is implicated in inflammatory, metabolic, psychiatric, and neurological disorders. While the gastrointestinal tract produces melatonin at levels far exceeding the pineal gland, its role in gut microbiota dynamics and circadian maturation remains unclear. This observational study investigates the association between fecal melatonin levels and microbial diversity, specific bacterial taxa (ZOTUs), actimetry-based sleep metrics, and various time-dependent factors (including stool timing and intervals since the last stool, sleep, and meal) in infants at 3, 6, and 12 months of age. Key findings include: (1) fecal melatonin levels increase with age but show high inter-individual variability; (2) fecal melatonin is associated with time factors, such as stool timing and time since last stool; (3) higher fecal melatonin levels are linked with reduced gut microbial richness and diversity; (4) the number of bacterial taxa associated with fecal melatonin decline over time; (5) melatonin is associated with age-dependent shifts in both bacterial phyla and genera, notably increasing phyla Actinobacteriota and Bacteroidota, and genera Bifidobacterium, and Veillonella, while reducing the phylum Firmicutes and the genus Streptococcus; (6) fecal melatonin is linked to circadian maturation; and (7) finally, stool timing variability and fasting time affect fecal melatonin stability. These findings identify intestinal melatonin as a promising biomarker for gut microbiota development and circadian rhythm establishment. In addition, these insights highlight melatonin in infant stool as a biomarker and potential modulator bridging systems of intestinal microbiota and behavioral sleep-wake organization.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13125696/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147793793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revitalizing the \"biology\" in \"chronobiology\".","authors":"Carl Hirschie Johnson, Charlotte Helfrich-Förster, Roelof A Hut, Sarah E Reece, William J Schwartz","doi":"10.1038/s44323-026-00078-0","DOIUrl":"10.1038/s44323-026-00078-0","url":null,"abstract":"<p><p>Studies of biological timekeeping have now matured from investigations of a fascinating and ubiquitous phenomenon into a discipline with practical applications; the excitement surrounding such translation has been overwhelming, perhaps at the expense of eclipsing further pursuit of basic research. Here we advocate that the ultimate success of applying chronobiological principles to address human and environmental needs will depend on the continued support of a robust agenda of fundamental research.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13125519/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147793948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time after time: a quarter century of progress in plant circadian biology.","authors":"Stacey L Harmer","doi":"10.1038/s44323-026-00076-2","DOIUrl":"10.1038/s44323-026-00076-2","url":null,"abstract":"<p><p>The past 25 years have seen remarkable progress in plant circadian biology. This perspective highlights major advances in our understanding of the oscillator network, the processes it regulates, and circadian variation across tissues and cell types. Genomic and systems approaches uncovered pervasive circadian control of physiology, development, and fitness, including photoperiodic and domestication traits. Emerging tools now position the field to engineer clocks for agricultural resilience in a changing climate.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13125627/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147793862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the biological impacts of nightlights: implications for sleep and circadian health in children.","authors":"Gena L Glickman, Rebecca Rothstein-Epp, Kyle Binkowski, Sebastian M M Preilipper, Ava Santiago, Sara C Bessman, Alexandra Easterling, Elizabeth M Harrison","doi":"10.1038/s44323-026-00072-6","DOIUrl":"10.1038/s44323-026-00072-6","url":null,"abstract":"<p><p>Given the widespread use of nightlights, we characterized an assortment of popular products to evaluate their potential to disrupt sleep and circadian rhythms in children. Spectral irradiance was measured for 25 top-rated nightlights (79 settings) under laboratory (source-level) and simulated bedroom (typical use) conditions. Nightlights varied in form (handheld, projector, tabletop, wall plug-in) as well as intensity and color settings. Melanopic equivalent daylight illuminance (EDI) estimated circadian input and was compared against biologically relevant thresholds for pediatric sleep. Across conditions, melanopic EDI values spanned several orders of magnitude, from 0 lx to >100,000 lx, with some devices varying substantially by setting. With source-level characterizations, only 3/25 products consistently remained below 5 lx melanopic EDI (levels known to phase shift circadian rhythms and suppress melatonin in children), and 2 also met the <1 lx consensus nighttime recommendation for adults. Under typical-use conditions, 14/25 products remained below 5 lx melanopic EDI (11 were <1 lx) on at least one setting, with most being red-toned, low-intensity, and positioned farther from the bed, though many of those would not support vision. Clear clinical guidance, public health recommendations, and improved product labeling standards are needed to reduce circadian disruption and promote healthier sleep in children.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13046988/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147611133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field assessment of melatonin timing reveals circadian misalignment beyond chronotype in elite female football players.","authors":"Cátia Reis, Rita Tomás, Vasco Cardoso, Júlio A Costa, João Brito","doi":"10.1038/s44323-026-00074-4","DOIUrl":"10.1038/s44323-026-00074-4","url":null,"abstract":"<p><p>Melatonin production is the gold-standard marker of the physiological \"biological night\". Assessing it in athletes outside the laboratory enables individualized circadian interventions. This study quantified morning misalignment in elite athletes and examined its association with subjective well-being. Twenty-two elite female athletes (mean age = 26.8 ± 4.3 years) from the same national squad were monitored during a one-week training camp with standardized meal, training and sleep opportunities. Athletes wore actimetry devices to measure sleep and light exposure and completed daily sleep diaries with well-being ratings. On one day, salivary melatonin was self-sampled hourly from four hours before habitual sleep onset to one hour after, and again at wake time and one hour after waking. A longer phase angle between melatonin onset and sleep onset was associated with longer total sleep duration, whereas being an evening chronotype and sharing a room with a dissimilar chronotype were both independently associated with shorter total sleep duration. Elevated melatonin one hour after waking, indicative of morning circadian misalignment, was associated with lower subjective well-being. These findings demonstrate that real-life circadian timing influences both sleep and well-being in elite athletes and support the value of individualized circadian-informed strategies to optimize health and recovery.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13043867/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147597482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Timed exercise modulates inter-coupling strength between evening and morning oscillators in mice.","authors":"Nagomi Miyagi, Noriko Matsuura, Yujiro Yamanaka","doi":"10.1038/s44323-026-00075-3","DOIUrl":"10.1038/s44323-026-00075-3","url":null,"abstract":"<p><p>The present study examined the effect of daily exposure to a novel cage equipped with a running wheel (NCRW) at two different times of day on the coupling strength between the evening (E) and morning (M) oscillators in nocturnal rodents. Adult male C57BL/6 mice (2-4 months old) were individually housed in cages without running wheels and maintained under a 12:12 h light-dark (LD) cycle with ad libitum access to food and water. Daily 3‑h exposure to the NCRW was conducted on five consecutive days per week for three weeks (19 days total) at either ZT12 (zeitgeber time: ZT, ZT12 = dark onset of the LD cycle) or ZT21. To assess effects on circadian behavioral rhythms, we performed three experiments: (1) measurement of the free-running period under constant darkness (DD), (2) assessment of the reentrainment rate to an 8-h phase advance of the LD cycle, and (3) analysis of phase shifts induced by a single 8-h advanced LD cycle. Exposure to NCRW at ZT12 significantly shortened the free-running period and facilitated reentrainment of activity onset to the advance of the LD cycle. In contrast, exposure to the NCRW at ZT21 lengthened the free-running period and significantly decelerated reentrainment of activity onset compared with the control condition. These results suggest that exposure to NCRW at ZT12 enhances the coupling strength of the E oscillator to the M oscillator, whereas exposure to NCRW at ZT21 enhances the coupling strength of the M oscillator to the E oscillator. These findings indicate that timed exercise under the LD cycle phase dependently modulates inter-oscillator coupling strengths and light-induced phase resetting, thereby influencing the regulation of activity onset and offset in nocturnal rodents.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13031686/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Auxiliary data, quality assurance and quality control for wearable light loggers and optical radiation dosimeters.","authors":"Johannes Zauner, Oliver Stefani, Gianfranco Bocanegra, Carolina Guidolin, Björn Schrader, Ljiljana Udovicic, Manuel Spitschan","doi":"10.1038/s44323-025-00067-9","DOIUrl":"10.1038/s44323-025-00067-9","url":null,"abstract":"<p><p>Wearable light loggers and optical radiation dosimeters are increasingly used in chronobiology and circadian health research, yet their data often lack contextual information (e.g., sleep, activity, environmental conditions) and may be compromised by non-wear periods, compliance issues, or technical faults. To address these limitations, we conducted interviews (n = 21) and a survey (n = 16) with domain experts to distil and iteratively develop auxiliary data and quality-control strategies aimed at improving the accuracy and interpretability of wearable light measurements. From this process, we established a six-domain auxiliary data framework encompassing wear/non-wear logging, sleep monitoring, light-source context, participant behaviour, user experience, and environmental light levels. Survey responses showed strong consensus on the value of auxiliary information (importance 4.0/5), with sleep and wear-time tracking rated as the most essential additions. To support practical adoption, we provide implementation tools, including extensions to the open-source R package LightLogR, enabling streamlined integration of wearable and auxiliary data as well as systematic quality assurance and control. Experts agreed that combining contextual records with rigorous QA/QC procedures substantially improves the reliability of field-collected light-exposure data. These recommendations and tools aim to help researchers in chronobiology, wearable sensing, and health sciences maximise data quality and enhance interpretation in real-world light-exposure studies.</p>","PeriodicalId":501704,"journal":{"name":"npj Biological Timing and Sleep","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12972172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147392188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}