Clocks & Sleep最新文献

{"title":"Salivary Aldosterone as a Biomarker for Obstructive Sleep Apnea: Diagnostic Performance and the Moderating Role of Mean Arterial Pressure-A Cross-Sectional Study.","authors":"Ziyuan Chen, May Nak Lau, Tengku Nurfarhana Nadirah Tengku Hamzah, Aida Nur Ashikin Abd Rahman, Liang Chye Goh, Mang Chek Wey","doi":"10.3390/clockssleep8030047","DOIUrl":"10.3390/clockssleep8030047","url":null,"abstract":"<p><p>Obstructive sleep apnea (OSA) is associated with renin-angiotensin-aldosterone system (RAAS) dysregulation. This study examined the relationship between salivary aldosterone and OSA severity, identified predictors of salivary aldosterone, evaluated the moderating role of mean arterial pressure (MAP), and compared the diagnostic performance of salivary aldosterone with the STOP-BANG questionnaire. This cross-sectional study included 67 adults grouped as healthy or mild OSA (apnea-hypopnea index [AHI] < 15; <i>n</i> = 34) versus moderate-to-severe OSA (AHI ≥ 15; <i>n</i> = 33). Morning salivary aldosterone was measured using enzyme-linked immunosorbent assay. Generalized linear models assessed independent predictors, MAP moderation was tested using PROCESS Model 1, and diagnostic performance was evaluated using receiver operating characteristic analysis. Salivary aldosterone did not differ between OSA severity groups and showed poor diagnostic performance. Age was negatively associated with aldosterone levels, while MAP moderated the relationship between AHI and salivary aldosterone. In contrast, the STOP-BANG questionnaire demonstrated acceptable discriminative ability and significantly higher specificity. Salivary aldosterone is not a reliable standalone OSA screening biomarker. However, MAP moderated the OSA-aldosterone relationship, suggesting potential utility in OSA patients with elevated MAP. Age independently predicted lower aldosterone, likely reflecting age-related RAAS decline. These findings support selective utility of salivary aldosterone in OSA patients with elevated blood pressure.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13510994/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148832694","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":"Longitudinal Changes in Pictorial Declarative Memory After Six Months of Clinical Management in Adults with Suspected Obstructive Sleep Apnea: A Prospective Cohort Study.","authors":"Ainhoa Álvarez-Ruiz-Larrinaga, Jorge Ullate, Alejandro Horrillo-Maysonnial, Carla Pía, Carlos Egea-Santaolalla, David Gozal, Joaquin Durán-Cantolla, Maria Comas","doi":"10.3390/clockssleep8030046","DOIUrl":"10.3390/clockssleep8030046","url":null,"abstract":"<p><strong>Background: </strong>Obstructive sleep apnea (OSA) has been implicated in declarative memory impairment. Here, we evaluated immediate recall and overnight declarative memory in patients with suspected OSA before and after standard clinical management in a longitudinal cohort of 265 patients.</p><p><strong>Methods: </strong>A nocturnal polysomnographic study (PSG) was performed at baseline and repeated six months later. The Pictorial-Based Declarative Memory Questionnaire (PDMQ) was administered and consisted of four learning trials followed by free-recall 10 min before PSG and the following morning upon awakening. The primary cognitive endpoint was the change in pictorial declarative memory performance from baseline to 6-month follow-up, expressed as the number of correctly recalled items on the PDMQ.</p><p><strong>Results: </strong>Both immediate and delayed recall performances significantly improved in the no OSA/mild OSA and severe OSA groups, whereas only immediate recall improved in the moderate OSA group. In the severe group, comparisons between patients whose apnea-hypopnea index decreased to <30 events/hour and those whose AHI remained >30 revealed significant cognitive improvements in both subgroups, particularly in initial and late trials (Trials 1, 2, 5, 6). In multivariable models, baseline PDMQ performance and indices of SpO₂ desaturation and sleep fragmentation emerged as independent predictors of change in declarative memory.</p><p><strong>Conclusions: </strong>These findings suggest that routine clinical management of patients with OSA was accompanied by modest, albeit statistically significant improvements in declarative memory, and that both intermittent hypoxia and sleep fragmentation play important roles in memory change.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13510326/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148832654","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":"Sleep Duration and Body Mass Index Among Adolescents: Variation by Age and Race/Ethnicity.","authors":"Astrid N Zamora, Zachary P Gersten, Erica C Jansen","doi":"10.3390/clockssleep8030045","DOIUrl":"10.3390/clockssleep8030045","url":null,"abstract":"<p><p>Sleep characteristics have been associated with body mass index (BMI) among adolescents, but population-representative evidence on sleep timing and variation across demographic subgroups remains limited. We conducted a cross-sectional analysis of 2017-2018 California Health Interview Survey data from 880 adolescents aged 12-17 years. Weeknight sleep duration was obtained from the CHIS-derived sleep-duration variable, based on reported school-night bedtimes and school-day wake times. Sleep-timing measures included bedtime, wake time, and the derived sleep midpoint. Pooled survey-weighted linear and logistic regression models used 160 jackknife replicate weights and adjusted for age, sex, race/ethnicity, household poverty category, and survey year; sensitivity models additionally adjusted for dietary and behavioral factors. Sleep duration was not associated with BMI overall (<i>p</i> = 0.161) or with the odds of having overweight or obesity (<i>p</i> = 0.36). The association between sleep duration and BMI varied by age group (<i>p</i> for interaction = 0.042). Each additional hour of sleep was associated with a lower BMI among adolescents aged 14-17 years (β = -0.895 kg/m²; 95% CI: -1.464 to -0.326; <i>p</i> = 0.002), but not among those aged 12-13 years. However, there was no evidence of an interaction when age was modeled continuously (<i>p</i> for interaction = 0.36). Bedtime, wake time, and sleep midpoint were not independently associated with BMI. Exploratory evidence that the association between sleep duration and overweight or obesity varied by race/ethnicity was attenuated after adjustment for dietary and behavioral factors (<i>p</i> for interaction changed from 0.04 to 0.05). In this cross-sectional study, neither sleep duration nor sleep timing was associated with BMI in the overall sample, and sleep duration was not associated with BMI-defined weight status. Subgroup findings were not consistent across model specifications and should be examined in longitudinal studies using objective and repeated measures of sleep.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13511623/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148832689","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":"How Well Do Young Male Semi-Professional Soccer Players Sleep During an Afternoon Nap?","authors":"Charli Sargent, Georgia Romyn, Michele Lastella, Dean J Miller, Gregory D Roach","doi":"10.3390/clockssleep8030044","DOIUrl":"10.3390/clockssleep8030044","url":null,"abstract":"<p><p>Athletes often experience situations in which they do not obtain adequate sleep at night. One strategy to overcome this issue is to supplement nighttime sleep with a daytime nap. However, little is known about how well athletes sleep during daytime naps. The aims of this study were to (i) determine the ability of athletes to fall asleep during an afternoon nap and (ii) examine the composition of the sleep obtained. In a counterbalanced, repeated-measures cross-over design, 12 young male semi-professional soccer players were given a 1 h (15:00-16:00) or 2 h (14:00-16:00) nap opportunity following a normal night's sleep (7-8 h time in bed) in a laboratory. Sleep was monitored using polysomnography and variables were compared between naps using generalized estimating equation models. In the 1 h nap, participants took 6.5 min to fall asleep and spent 52/60 min asleep (87% efficiency); in the 2 h nap, participants took 7.5 min to fall asleep and spent 105/120 min asleep (87% efficiency). There was no difference in wake after sleep onset (<i>p</i> = 0.168) or time spent in stage N3 sleep (<i>p</i> = 0.110) between the 1 h and 2 h nap, but participants fell asleep faster (<i>p</i> < 0.001), obtained more sleep (<i>p</i> < 0.001), and spent more time in stage N1 sleep (<i>p</i> = 0.003), stage N2 sleep (<i>p</i> < 0.001), and Stage REM sleep (<i>p</i> = 0.004) in the 2 h nap. Athletes sleep well during 1 h and 2 h afternoon naps and could use this as a strategy to help meet sleep duration recommendations (i.e., 7-9 h).</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398262/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580339","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":"Sleep-Wake Dysregulation in Human African Trypanosomiasis: From Neuroinvasion to Neuronal Dysfunction.","authors":"Seithikurippu R Pandi-Perumal, Ahmed S BaHammam, Konda Mani Saravanan","doi":"10.3390/clockssleep8030042","DOIUrl":"10.3390/clockssleep8030042","url":null,"abstract":"<p><p>Human African trypanosomiasis (HAT) or sleeping sickness is a neglected tropical disease with a progressive central nervous system (CNS) involvement and marked sleep and circadian rhythm abnormalities. Even though this is a prominent feature of HAT, the connection between parasite neuroinvasion, neuroinflammation, circadian dysfunction, and neurological impairment is not fully understood. This narrative review aims to summarize the most up-to-date knowledge about sleep and circadian disturbance in HAT and proposes an integrated approach for the Trypanosome-Associated Sleep Disorder (TASD). The relevant literature was identified by searching major biomedical databases for HAT, sleep disorders, circadian rhythms, neuroinflammation, and CNS invasion. The review covers the steps by which the CNS becomes invaded, how the barriers are disrupted, how the CNS becomes activated by inflammatory responses, and how the hypothalamic and circadian regulatory networks are disrupted. The evidence suggests that excessive daytime sleepiness, fragmented nocturnal sleep, circadian misalignment, and neuropsychiatric manifestations are related to the activation of inflammatory cytokines, altered neurotransmitter signaling, activation of the kynurenine pathway, dysregulation of clock genes, and disruption of the suprachiasmatic nucleus. We also discuss TASD as a syndrome-like phenotype of CNS involvement and propose a three-stage model of sleep-wake dysfunction in HAT. The review unites these integral mechanisms in a single mechanistic framework to offer a unified understanding of the sleep pathology associated with HAT. There are still important gaps in our knowledge of biomarkers, disease staging, and irreversible neuronal damage, which indicate priorities for future research and better clinical management.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13397988/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580416","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":"Mechanisms of Heat-Induced Sleep Disruption in Aging: A Narrative Review.","authors":"Neriman Ezgin, Jelena Krčum, Nikola Šutulović, Maja Pavlović, Emilija Djurić, Dušan Mladenović, Milena Vesković, Arif E Cetin, Aleksandra Rašić-Marković, Olivera Stanojlović, Dragan Hrnčić","doi":"10.3390/clockssleep8030043","DOIUrl":"10.3390/clockssleep8030043","url":null,"abstract":"<p><p>Rising global temperatures and more frequent heat waves pose a growing threat to public health, particularly among older adults. Age-related declines in thermoregulatory capacity such as reduced sweating, impaired vasodilation, and diminished hypothalamic responsiveness make it more difficult to cope with elevated nighttime temperatures. These thermal challenges disrupt sleep by prolonging sleep onset, fragmenting slow-wave and REM sleep, and suppressing melatonin secretion. Importantly, sex-related differences in thermoregulatory aging-particularly menopause-associated vasomotor instability in women and testosterone-related autonomic changes in men-further modulate individual vulnerability to heat-induced sleep disruption. Beyond sleep, heat-induced stress affects metabolic, cardiovascular, and immune systems, promoting insulin resistance, endothelial dysfunction, sympathetic overactivation, and chronic inflammation. Socioeconomic disparities, urban heat island exposure, and differential access to cooling infrastructure function as critical environmental modifiers that amplify biological vulnerability, particularly in disadvantaged older populations. This narrative review aims to synthesize current knowledge on the specific thermoregulatory mechanisms of sleep disruption induced by heat stress in older adults. Understanding these interactions is crucial for developing effective interventions, including environmental cooling, circadian-aligned behaviors, and targeted public health strategies, to mitigate the compounded risks of heat exposure and preserve healthy sleep in aging populations. However, many proposed mechanistic pathways are primarily derived from animal models, and controlled human studies specifically targeting heat-exposed older adults remain scarce.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13397976/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580303","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-of-Day Variations and Effects of Total Sleep Deprivation on Attention Assessed with the Attentional Demands Task.","authors":"Ilaria Di Pompeo, Martina Marcaccio, Giorgia Capitani, Assunta Pompili, Simone Migliore, Giuseppe Curcio","doi":"10.3390/clockssleep8030041","DOIUrl":"10.3390/clockssleep8030041","url":null,"abstract":"<p><p>Circadian rhythms, sleep homeostasis, and chronotype interact to modulate cognitive processes such as attention and executive functions, leading to fluctuations in performance throughout the day and significant impairments under conditions of misalignment or sleep deprivation. The study was conducted in two phases and included the assessment of subjective measures of sleepiness, vigor, affect, sleep quality, and individual chronotype. In the first phase, 32 healthy participants (19 females; mean age = 24.9 ± 3.14) were tested at four different times of the day to examine diurnal variations in attentional performance. In the second phase, a subsample of 8 participants (4 females; mean age = 24.4 ± 2.20) underwent a total sleep-deprivation protocol and completed the AD-Task over two consecutive days to evaluate the impact of prolonged wakefulness on attentional and executive functioning. In the first phase, results revealed a progressive decline in selective attention across the day (F_(3.93) = 3.188; <i>p</i> = 0.027; η²p = 0.093) and significantly slower reaction times in divided attention during the morning (F_(3.93) = 7.3134; <i>p</i> < 0.001; η²p = 0.191), indicating a time-of-day modulation of attentional resources. In the second phase, total sleep deprivation led to a marked impairment in performance, reflected by slower reaction times (F_(11.77) = 1.948; <i>p</i> = 0.046; η²p = 0.218) and reduced discriminative ability (d'; F_(11.77) = 13.438; <i>p</i> < 0.001; η²p = 0.657), particularly in task-switching conditions. These findings suggest increased vulnerability of executive functions under sleep deprivation, likely associated with reduced efficiency of prefrontal cortical processes. The results confirm that time of the day and pressure of sleep significantly affect attention and cognitive flexibility and further affirm the validity of the AD-Task as a reliable instrument for detecting these variations under ecologically relevant conditions.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398160/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580386","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":"Association of Sleep Patterns and Sleep Quality with Academic Performance Among Female University Students: Insights Supporting SDG 3 (Good Health and Well-Being).","authors":"Noorah Saleh Al-Sowayan, Lama Essam Aboselmiya","doi":"10.3390/clockssleep8030039","DOIUrl":"10.3390/clockssleep8030039","url":null,"abstract":"<p><strong>Background: </strong>Sleep quality plays an essential role in cognitive performance, memory consolidation, learning efficiency, and overall wellbeing. University students are particularly vulnerable to sleep disturbances because of academic stress, irregular sleep schedules, and lifestyle-related factors. Poor sleep quality has been associated with impaired academic performance and reduced cognitive functioning.</p><p><strong>Objective: </strong>This study aimed to evaluate the relationship between sleep patterns, sleep quality, and academic performance among female university students.</p><p><strong>Methods: </strong>A cross-sectional study was conducted among 201 female university students at Qassim University, Saudi Arabia. Data were collected using an electronic self-administered questionnaire that included demographic characteristics, sleep-related behaviors, and the Pittsburgh Sleep Quality Index (PSQI). Academic performance was assessed using self-reported Grade Point Average (GPA). Statistical analysis included descriptive statistics, Spearman correlation analysis, one-way ANOVA with Tukey post hoc analysis, Chi-square tests, and multiple linear regression analysis.</p><p><strong>Results: </strong>The mean GPA of the participants was 4.13 ± 0.60 (on a 5-point scale), while the mean PSQI score was 8.81 ± 3.26, indicating generally poor sleep quality. A significant negative correlation was observed between PSQI score and GPA (rho = -0.200, <i>p</i> = 0.0047). Students with good sleep quality demonstrated significantly higher GPA scores compared with students with poor sleep quality (F(2,194) = 6.31, <i>p</i> = 0.0022). Significant associations were also identified between sleep quality and both bedtime (<i>p</i> = 0.0009) and sleep duration category (<i>p</i> = 0.0002). However, after adjustment for other variables, the independent effect of PSQI on GPA was attenuated and did not reach statistical significance (<i>p</i> = 0.138). This discrepancy between the significant bivariate correlation (rho = -0.200, <i>p</i> = 0.005) and the non-significant multivariate result represents the most important finding of this study, suggesting that sleep quality alone does not independently predict GPA when other academic and behavioral factors are considered.</p><p><strong>Conclusion: </strong>Poor sleep quality was highly prevalent among female university students and showed a significant bivariate association with lower academic performance, though this relationship was attenuated in the multivariate model. Promoting healthy sleep behaviors may support student wellbeing and academic functioning, cognitive wellbeing, quality of life, and the advancement of Sustainable Development Goal 3 (Good Health and Well-Being).</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13397848/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580288","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":"Sleep Quality, Not Sleep Duration, Is Independently Associated with Internalized Weight Bias: The Greek Lifestyle and Obesity-Related Bias Survey.","authors":"Athina Tzifopoulou, Despoina Dragataki, Maria G Grammatikopoulou, Eleni C Pardali, Maria Dimitriou, Dimitrios Poulimeneas","doi":"10.3390/clockssleep8030040","DOIUrl":"10.3390/clockssleep8030040","url":null,"abstract":"<p><p>Internalized weight bias-the self-directed endorsement of weight-related stereotypes-has emerged as a psychologically potent correlate of health outcomes in individuals with overweight and obesity, yet its relationship with sleep remains largely unexplored. In a cross-sectional manner, 495 Greek adults with a history of overweight/obesity were assessed regarding sleep quality and duration, internalized weight bias (Modified Weight Bias Internalization Scale; WBIS-M), and expressed anti-fat attitudes (Anti-Fat Attitudes Questionnaire, AFA: Dislike, Fear of Fat, Willpower). Insomnia prevalence, assessed with the Athens Insomnia Scale (AIS), was high at 57.6%-nearly doubling across ascending WBIS-M tertiles (39.9% to 73.1%). In hierarchical linear regression models, AIS score remained independently associated with WBIS-M after adjustment for depression, anxiety, BMI, and a comprehensive range of sociodemographic and clinical covariates (B = 0.058; 95% CI: 0.036-0.079; <i>p</i> < 0.001), with the fully adjusted model explaining 58.5% of total variance in WBIS-M. AFA subscales did not remain significant in the model post-full adjustment, and sleep duration failed to show independent association with either bias dimensions. The sleep-weight bias association was therefore specific to the internalized dimension and to sleep quality, rather than quantity. These findings highlight a clinically relevant and dimension-specific link between insomnia symptoms and internalized weight stigma, and suggest that routine sleep assessment may be warranted in individuals with a history of overweight or obesity presenting with elevated internalized weight bias-and vice versa.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13397851/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580405","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":"Melatonin in Clinical Practice: Grey Zones Between Chronobiology, Insomnia and Consumer Supplementation.","authors":"Alexandros Kalkanis, Aliki Karkala, Athanasia Pataka","doi":"10.3390/clockssleep8030038","DOIUrl":"10.3390/clockssleep8030038","url":null,"abstract":"<p><p>Melatonin occupies a paradoxical position in contemporary sleep medicine: despite its physiological role as a regulator of circadian timing, it is frequently used and perceived as a nonspecific \"natural\" hypnotic. Although melatonin demonstrates modest benefits for sleep initiation and clearer efficacy in circadian rhythm sleep-wake disorders, its clinical use is often undermined by diagnostic imprecision, inappropriate dosing, mistimed administration, inconsistent formulations, and inadequate patient counseling. Circadian disorders can be misclassified as primary insomnia, leading to symptomatic treatment approaches that fail to address the underlying phase misalignment. At the same time, supraphysiological doses and reflexive bedtime administration have become normalized despite evidence that melatonin acts primarily as a chronobiotic whose effects depend more on timing than dose. Regulatory inconsistencies and substantial variability in over-the-counter preparations further complicate safe and reproducible use. These factors contribute to avoidable treatment failure, inaccurate labeling of nonresponse, and persistent misconceptions regarding melatonin's mechanism of action. Therefore, melatonin should be approached as a pharmacological intervention requiring the same diagnostic rigor, individualized dosing, and longitudinal assessment expected of other sleep therapeutics, particularly when integrated with behavioral and circadian interventions.</p>","PeriodicalId":33568,"journal":{"name":"Clocks & Sleep","volume":"8 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148580436","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}