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    2705 results match your criteria Chronobiology International [Journal]

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    Diurnal and seasonal changes in semen quality of men in subfertile partnerships.
    Chronobiol Int 2018 Jun 18:1-10. Epub 2018 Jun 18.
    a Department of Reproductive Endocrinology , University Hospital Zurich , Zurich , Switzerland.
    Circadian and circannual rhythms influence not only the environment, but also human physiology. In times of increasing numbers of couples struggling with infertility, and thus increasing demand for successful assisted reproduction, the aim of our study was to evaluate circadian and circannual rhythms and their association with semen quality. A total of 12 245 semen samples from 7068 men, collected at the andrology laboratory of the Department of Reproductive Endocrinology, University Hospital Zurich, between 1994 and 2015, were uniformly analysed in terms of sperm concentration, total sperm count, progressive motility and normal morphology. Read More

    Chronotype and environmental light exposure in a student population.
    Chronobiol Int 2018 Jun 18:1-10. Epub 2018 Jun 18.
    a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK.
    In humans and most other species, changes in the intensity and duration of light provide a critical set of signals for the synchronisation of the circadian system to the astronomical day. The timing of activity within the 24 h day defines an individual's chronotype, i.e. Read More

    Driving when distracted and sleepy: The effect of phone and passenger conversations on driving performance.
    Chronobiol Int 2018 Jun 12:1-4. Epub 2018 Jun 12.
    a Appleton Institute for Behavioural Science, Central Queensland University , Adelaide , Australia.
    This study investigates the effect of passenger and phone conversations on sleep-restricted driving. Six volunteers (50% male, mean age 24.8 ± 4. Read More

    Flat-out napping: The quantity and quality of sleep obtained in a seat during the daytime increase as the angle of recline of the seat increases.
    Chronobiol Int 2018 Jun 11:1-12. Epub 2018 Jun 11.
    a Appleton Institute for Behavioural Science , Central Queensland University , Adelaide , Australia.
    Some shiftwokers in the long-haul transportation industries (i.e. road, rail, sea, air) have the opportunity to sleep in on-board rest facilities during duty periods. Read More

    Convergent and construct validity and test-retest reliability of the Caen Chronotype Questionnaire in six languages.
    Chronobiol Int 2018 Jun 6:1-11. Epub 2018 Jun 6.
    o School of Psychology , University of Wollongong , Wollongong , Australia.
    Chronotype questionnaires provide a simple and time-effective approach to assessing individual differences in circadian variations. Chronotype questionnaires traditionally focused on one dimension of chronotype, namely its orientation along a continuum of morningness and eveningness. The Caen Chronotype Questionnaire (CCQ) was developed to assess an additional dimension of chronotype that captures the extent to which individual functioning varies during the day (amplitude). Read More

    Lunacy revisited - the myth of the full moon: are football injuries related to the lunar cycle?
    Chronobiol Int 2018 Jun 6:1-6. Epub 2018 Jun 6.
    b ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital , Doha , Qatar.
    Previous literature suggests that human behaviour and physiology are somehow altered by the moon-cycle, with particular emphasis on poorer sleep quality and increased aggressive behaviour during full moon. The latter variables can negatively impact athletes' recovery and increase the likelihood of injury resulting from collision with another athlete. Therefore, the current study aimed to investigate the association between the lunar cycle and injury risk in professional football players (soccer). Read More

    Daily, weekly and annual patterns in children's accidental sport injuries.
    Chronobiol Int 2018 May;35(5):597-616
    c Department of Biomedical Engineering , The University of Texas at Austin, Cockrell College of Engineering , Austin , Texas , USA.
    Details of serious injuries to children ≤16 yrs. of age that necessitated urgent surgical intervention by the Department of Pediatric Surgery of the University Hospital of Lausanne, Switzerland were recorded into a database registry. Some 15 110 entries listed the precise time of injury, and 3114 (20. Read More

    Daily rhythms after vaccination on specific and non-specific responses in Nile tilapia (Oreochromis niloticus).
    Chronobiol Int 2018 May 31:1-14. Epub 2018 May 31.
    c Laboratory of Feeding Behavior and Fish Nutrition (AquaUFRB), Faculty of Fish Engineering (NEPA), Center of Agricultural Sciences, Environmental and Biological (CCAAB), Campus Cruz das Almas , Federal University of Bahia (UFRB) , Bahia , Brazil.
    We evaluated the daily changes in immunological and hematological factors in tilapia (Oreochromis niloticus) after an immunization period with a subsequent challenge. Experiments were divided into two phases: Phase 1 (immunization): 144 fish were distributed into two groups with 72 fish in six tanks. One group (T1) was immunized, comprising six vaccination time points (ZT schedule = ZT2 h, ZT6 h, ZT10 h, ZT14 h, ZT18 h, ZT22 h). Read More

    Anxiety symptomatology, sex and chronotype: The mediational effect of diurnal sleepiness.
    Chronobiol Int 2018 May 31:1-11. Epub 2018 May 31.
    e School of Nursing , Universidad de Ciencias Aplicadas y Ambientales. U.D.C.A , Bogotá , Colombia.
    Diurnal subjective sleepiness has been associated with a large number of negative outcomes, such as increased risk of accidents and development of mental disorders as depression and anxiety. However, the role of the diurnal subjective sleepiness as a mediator is poorly understood. The goal of the present study was to examine the role of diurnal subjective sleepiness as a mediator of the relationship between sex, chronotype and anxiety symptoms in healthy young adults. Read More

    Melatonin ingestion after exhaustive late-evening exercise improves sleep quality and quantity, and short-term performances in teenage athletes.
    Chronobiol Int 2018 May 30:1-13. Epub 2018 May 30.
    g National Observatory of Sport , Tunis , Tunisia.
    The present study aimed to explore the effects of a single 10-mg dose of melatonin (MEL) administration after exhaustive late-evening exercise on sleep quality and quantity, and short-term physical and cognitive performances in healthy teenagers. Ten male adolescent athletes (mean ± SD, age = 15.4 ± 0. Read More

    Athletes underestimate sleep quantity during daytime nap opportunities.
    Chronobiol Int 2018 May 29:1-3. Epub 2018 May 29.
    a Appleton Institute for Behavioural Science , Central Queensland University , Adelaide , Australia.
    This study examined the difference between athletes' self-reported and objective sleep durations during two nap opportunities. Twelve well-trained male soccer players' sleep durations were assessed using polysomnography and a self-report question during a 60- and 120-min nap opportunity. Participants underestimated sleep compared to objective sleep assessments for both the 60-min nap opportunity (p = 0. Read More

    Changes in phase-angle under light-dark cycles influenced by nonphotic stimulation.
    Chronobiol Int 2018 May 29:1-12. Epub 2018 May 29.
    a Biology Department , University of Wisconsin-Eau Claire , Eau Claire , WI , USA.
    Most work looking at nonphotic effects on circadian rhythms is conducted when animals are held under freerunning conditions, usually constant darkness. However, for nonphotic effects to be functionally significant, they should be demonstrable under conditions in which most animals live, i.e. Read More

    No association of moon phase with stroke occurrence.
    Chronobiol Int 2018 May 23:1-7. Epub 2018 May 23.
    f Research Centre of Applied and Preventive Cardiovascular Medicine , University of Turku , Turku , Finland.
    Stroke occurrence shows strong correlations with sleep disorders and even subtle sleep disturbances have been shown to affect ischemic stroke (IS) occurrence. Chronobiology also exerts effects, like the morning surge in IS occurrence. Lunar cycles have also been shown to affect sleep and other physiological processes, but studies on moon phases and its possible association with occurrence of stroke are rare and nonconclusive. Read More

    Functional changes of the SCN in spontaneous hypertension but not after the induction of hypertension.
    Chronobiol Int 2018 May 22:1-15. Epub 2018 May 22.
    a Hypothalamic Integration Mechanisms , Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam , The Netherlands.
    The present study investigates the circadian behavior of spontaneously hypertensive rats (SHRs) during the pre-hypertensive and hypertensive stage, with the aim to gain insight into whether observed changes in the functionality of suprachiasmatic nucleus (SCN) in the hypertensive state are cause or consequence of hypertension. Four types of animals were used in this study: (1) SHRs which develop hypertension genetically; (2) their normotensive controls, Wistar Kyoto rats (WKYs); (3) Wistar rats whereby hypertension was surgically induced (2 Kidney 1 Clamp (2K1C) method); and (4) sham-operated control Wistar rats. Period length and activity levels and amplitude changes of locomotor and wheel running activity were determined, in constant conditions, as a measure of the functionality of the SCN. Read More

    Alertness and psychomotor performance levels of marine pilots on an irregular work roster.
    Chronobiol Int 2018 May 22:1-12. Epub 2018 May 22.
    a Centre for Study and Treatment of Circadian Rhythms, Douglas Hospital Research Centre, Department of Psychiatry , McGill University , Montreal , Canada.
    Fatigue is recognized as an important safety concern in the transportation industry. In this study, our goal was to investigate how circadian and sleep-wake dependent factors influence St-Lawrence River pilots' sleep-wake cycle, alertness and psychomotor performance levels at work. A total of 18 male St-Lawrence River ship pilots were recruited to a 16-21-day field study. Read More

    Chronotherapy of maxacalcitol on skin inflammation induced by topical 12-O-tetradecanoylphorbol-13-acetate in mice.
    Chronobiol Int 2018 May 18:1-12. Epub 2018 May 18.
    a Division of Clinical Pharmacology, Department of Pharmacology , Jichi Medical University , Tochigi , Japan.
    In general, chronotherapy is desirable for a more effective and/or safe dosage regimen. In this study, a daily rhythm of skin vitamin D receptor (VDR) and chronotherapeutic profiles of maxacalcitol, a vitamin D analogue, were evaluated using mice with skin inflammation induced by topical 12-O-tetradecanoylphorbol-13-acetate (TPA). This study showed that skin nuclear VDR expression in TPA-treated mice has a daily rhythm with the peak at the middle of active period. Read More

    Population-level study links short-wavelength nighttime illumination with breast cancer incidence in a major metropolitan area.
    Chronobiol Int 2018 May 16:1-11. Epub 2018 May 16.
    a Department of Natural Resources and Environmental Management , University of Haifa , Haifa , Israel.
    Several population-level studies revealed a positive association between breast cancer (BC) incidence and artificial light at night (ALAN) exposure. However, the effect of short-wavelength illumination, implicated by laboratory research and small-scale cohort studies as the main driving force behind BC-ALAN association, has not been supported by any population-level study carried out to date. We investigated a possible link between BC and ALAN of different subspectra using a multi-spectral year-2011 satellite image, taken from the International Space Station, and superimposing it with year-2013 BC incidence data available for the Great Haifa Metropolitan Area in Israel. Read More

    Examining courses of sleep quality and sleepiness in full 2 weeks on/2 weeks off offshore day shift rotations.
    Chronobiol Int 2018 May 16:1-14. Epub 2018 May 16.
    a Department of Health Sciences, Community and Occupational Medicine , University Medical Center Groningen, University of Groningen , Groningen , The Netherlands.
    To better understand sleep quality and sleepiness problems offshore, we examined courses of sleep quality and sleepiness in full 2-weeks on/2-weeks off offshore day shift rotations by comparing pre-offshore (1 week), offshore (2 weeks) and post-offshore (1 week) work periods. A longitudinal observational study was conducted among N=42 offshore workers. Sleep quality was measured subjectively with two daily questions and objectively with actigraphy, measuring: time in bed (TIB), total sleep time (TST), sleep latency (SL) and sleep efficiency percentage (SE%). Read More

    Permanent night workers´ sleep and psychosocial factors in hospital work. A comparison to day and shift work.
    Chronobiol Int 2018 May 15:1-10. Epub 2018 May 15.
    a Work ability and working careers , Finnish Institute of Occupational Health , Helsinki , Finland.
    We aimed to study whether permanent night workers sleep and psychosocial factors differ from day workers and shift workers. The participants (n = 9 312, 92% females, average age 45 years, most commonly nurses and departmental secretaries) were day workers (DW, n = 2 672), shift workers (SW, n = 6 486) and permanent night workers (PNW, n = 154). The Finnish Public Sector survey responses from six hospital districts from 2012 were combined to payroll data from 91 days preceding the survey. Read More

    Morningness-eveningness preferences, learning approach and academic achievement of undergraduate medical students.
    Chronobiol Int 2018 May 15:1-7. Epub 2018 May 15.
    a Department of Medicine, Dow Medical College , Dow University of Health Sciences , Karachi , Pakistan.
    Several studies have focused on determining the effect of chronotype and learning approach on academic achievement separately indicating that morning types have an academic advantage over the evening types and so have the deep learners over the surface learners. But, surprisingly none have assessed the possible relationship between chronotype and learning approach. So, the current study aimed to evaluate this association and their individual influence on academic performance as indicated by the Cumulative Grade Point Average (CGPA) as well as the effect of their interaction on academic performance. Read More

    Coping with shift work-related circadian disruption: A mixed-methods case study on napping and caffeine use in Australian nurses and midwives.
    Chronobiol Int 2018 May 15:1-12. Epub 2018 May 15.
    a Sleep & Chronobiology Laboratory , University of South Australia , Adelaide , Australia.
    Introduction: Two of the most ubiquitous fatigue countermeasures used by shift-working nurses are napping and caffeine. This mixed-methods case study investigated the ways nurses and midwives utilised napping and caffeine countermeasures to cope with shift work, and associated sleep, physical health and psychological health outcomes.

    Materials And Methods: N = 130 Australian shift-working nurses and midwives (mean age = 44 years, range = 21-67, 115F, 15M) completed the Standard Shiftwork Index. Read More

    Chronotype and depressive symptoms in students: An investigation of possible mechanisms.
    Chronobiol Int 2018 May 15:1-14. Epub 2018 May 15.
    a Department of Clinical Psychology, Institute of Psychology , Leiden University , Leiden , The Netherlands.
    Individuals with an evening chronotype are at increased risk of experiencing emotional problems, including depressive symptoms. However, the mechanisms underlying these associations remain unclear. The present study aimed to determine whether poor sleep quality, substance use and cognitive emotion regulation difficulties - which have been implicated in the etiology of depression - mediate the relationship between chronotype and depressive symptoms in a student sample, which was assessed cross-sectionally and after 1 year. Read More

    Payroll data based description of working hours in the Danish regions.
    Chronobiol Int 2018 May 15:1-6. Epub 2018 May 15.
    a National Research Centre for the Working Environment , Copenhagen , Denmark.
    The aim was to describe the organization of working hours in the Danish regions according to sex, age and calendar year. Based on the Danish Working Hour Database (DWHD), individuals were classified according to schedules: Permanent day (57.8%), evening (1. Read More

    Myotonic dystrophytype 1 - report of non-24-h sleep-wake disorder with excessive daytime sleepiness.
    Chronobiol Int 2018 May 15:1-3. Epub 2018 May 15.
    a Departamento de Neurologia e Neurocirurgia , Universidade Federal de São Paulo , São Paulo , Brasil.
    Myotonic dystrophy (MD) is a neuromuscular disease with myotonia, progressive weakness, and involvement of CNS, heart, and gastrointestinal system. Excessive daytime sleepiness (EDS) in myotonic dystrophy type 1 (MD1) is related to sleep breathing diseases, restless leg syndrome, periodic limb movements during sleep and narcoleptic-like phenotype. However, authors highlight a central dysfunction of sleep regulation. Read More

    Chronotype influences response to antidepressant chronotherapeutics in bipolar patients.
    Chronobiol Int 2018 May 15:1-7. Epub 2018 May 15.
    a Department of Clinical Neurosciences , Scientific Institute and University Vita-Salute San Raffaele , Milan , Italy.
    Patient diurnal mood fluctuation, sleep characteristics and factors affecting sleep homeostasis predict antidepressant response to the combination of total sleep deprivation and light therapy (TSD + LT). In order to study if chronotype could influence response to TSD+LT, we considered 194 bipolar depressed patients. Severity of depression was rated with Hamilton Depression Rating Scale; perceived mood levels were assessed by a self-administered 10-cm visual analogue scale and chronotype was assessed using the Mornigness-Eveningness Questionnaire. Read More

    No rest for the women: Understanding the impact of on-call work for women in the emergency services.
    Chronobiol Int 2018 May 11:1-11. Epub 2018 May 11.
    a Appleton Institute , CQUniversity , Adelaide , Australia.
    Background: The unpredictable, "on-call" component of the emergency services (ES) may be difficult to navigate in the context of domestic and work responsibilities, and especially difficult for women, given they tend to take on a greater household burden than do men. Our aim was to understand women's experiences in the ES, particularly the impact of being on-call and related coping strategies.

    Methods: Twenty-four women were recruited from two ES agencies in Australia. Read More

    Association of urinary levels of 6-sulfatoxymelatonin (aMT6s) with prevalent and incident hypertension.
    Chronobiol Int 2018 May 11:1-7. Epub 2018 May 11.
    a Department of Biostatistics and Epidemiology , University of Massachusetts , Amherst , MA , USA.
    Laboratory studies indicate that melatonin has beneficial vascular effects. However, epidemiologic studies on the relationship between endogenous levels of melatonin and hypertension in humans are limited. We examined the association of quartile levels of 6-sulfatoxymelatonin (aMT6s) in first morning urines with prevalent and incident hypertension in 777 postmenopausal women who were originally part of a case-control study of breast cancer nested in the Women's Health Initiative Observational Study. Read More

    How well does a commercially available wearable device measure sleep in young athletes?
    Chronobiol Int 2018 May 11:1-5. Epub 2018 May 11.
    a Appleton Institute for Behavioural Science , Central Queensland University , Goodwood , Australia.
    The validity of a commercially available wearable device for measuring total sleep time was examined in a sample of well-trained young athletes during night-time sleep periods and daytime naps. Participants wore a FitBit HR Charge on their non-dominant wrist and had electrodes attached to their face and scalp to enable polysomnographic recordings of sleep in the laboratory. The FitBit automatically detected 24/30 night-time sleep periods but only 6/20 daytime naps. Read More

    Does breaking up prolonged sitting when sleep restricted affect postprandial glucose responses and subsequent sleep architecture? - a pilot study.
    Chronobiol Int 2018 May 11:1-6. Epub 2018 May 11.
    a Health, Medical and Applied Sciences , Central Queensland University , Wayville , Australia.
    This pilot study investigated the impact of breaking up prolonged sitting with light-intensity walking on postprandial glucose responses and sleep architecture. In a randomized, counterbalanced, crossover design, six healthy males completed a sitting condition and an active condition (sitting interrupted with light-intensity walking) for three consecutive days, following 5-h sleep opportunities at night. Postprandial glucose response and sleep (time spent in all stages) was assessed. Read More

    Predictors of response to combined wake and light therapy in treatment-resistant inpatients with depression.
    Chronobiol Int 2018 May 11:1-12. Epub 2018 May 11.
    g Glostrup, Mental Health Centre Glostrup , Copenhagen University Hospital , Glostrup , Denmark.
    There is growing evidence for combined chronotherapeutic interventions as adjunctive treatments for major depression. However, as the treatments can be demanding, we need to identify predictors of response. This study aimed to describe predictors of response, remission and deterioration in the short-term phase, as well as predictors of long-term response. Read More

    Uncertain call likelihood negatively affects sleep and next-day cognitive performance while on-call in a laboratory environment.
    Chronobiol Int 2018 May 11:1-11. Epub 2018 May 11.
    a Appleton Institute, School of Human, Health and Social Sciences , Central Queensland University , Wayville , SA , Australia.
    On-call working arrangements are employed in a number of industries to manage unpredictable events, and often involve tasks that are safety- or time-critical. This study investigated the effects of call likelihood during an overnight on-call shift on self-reported pre-bed anxiety, sleep and next-day cognitive performance. A four-night laboratory-based protocol was employed, with an adaptation, a control and two counterbalanced on-call nights. Read More

    The impact of shift work on eating patterns and self-care strategies utilised by experienced and inexperienced nurses.
    Chronobiol Int 2018 May 8:1-10. Epub 2018 May 8.
    c Department of Employment Relations and Human Resource Management , Griffith University.
    For nurses, shift work is a necessity, required to provide 24-h continuous care for patients. Research posits that fatigue amongst shift-working nurses is associated with inadequate and poorly timed sleep and also strongly influenced by the timing, quality and quantity of food consumed. The aim of this investigation was to examine differences and similarities in the food choices and eating patterns of nurses exposed to different lengths of time in shift work, as a means of understanding how nurses can adapt their eating patterns to better manage fatigue and sleep loss. Read More

    Sleep quality, sleepiness and the influence of workplace breaks: A cross-sectional survey of health-care workers in two US hospitals.
    Chronobiol Int 2018 May 8:1-4. Epub 2018 May 8.
    b Sleep and Performance Research Center , Washington State University , Spokane , WA , USA.
    This study assessed sleep quality, sleepiness and use of workplace break opportunities in 1285 health-care workers via an online questionnaire. Two hospitals were surveyed - one with and one without a fatigue mitigation policy. Across all respondents, 68. Read More

    Associations between chronotype, sleep disturbances and seasonality with fatigue and inflammatory bowel disease symptoms.
    Chronobiol Int 2018 May 8:1-11. Epub 2018 May 8.
    e Department of Affective Disorders, Medical College , Chair of Psychiatry, Jagiellonian University , Cracow , Poland.
    Growing number of studies suggests link between circadian rhythms and inflammatory bowel diseases (IBD) manifestation. We hypothesize that: 1) IBD are associated with increased eveningness and sleep disturbances; 2) eveningness and sleep disturbances are related to more severe IBD symptoms. In total, 129 participants were enrolled to this study, divided into three groups: 34 Crohn's disease (CD) patients, 38 ulcerative colitis (UC) patients and 57 healthy controls (HC) group. Read More

    Involvement of cortisol and sirtuin1 during the response to stress of hypothalamic circadian system and food intake-related peptides in rainbow trout, Oncorhynchus mykiss.
    Chronobiol Int 2018 May 8:1-20. Epub 2018 May 8.
    a Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro Singular de Investigación Mariña-ECIMAT , Universidade de Vigo , Spain.
    Stress is conditioning animal welfare by negatively affecting a wide range of physiological and behavioral functions. This may be applied to circadian physiology and food intake. Cortisol, the stress-related hormone, may mediate such effect of stress, but other indirect mediators might be considered, such as sirtuin1. Read More

    Constant light during lactation programs circadian and metabolic systems.
    Chronobiol Int 2018 Apr 24:1-15. Epub 2018 Apr 24.
    a Facultad de Medicina , Universidad Nacional Autónoma de México, UNAM , Mexico City , México.
    Exposure to light at night is a disruptive condition for the adult circadian system, leading to arrhythmicity in nocturnal rodents. Circadian disruption is a risk factor for developing physiological and behavioral alterations, including weight gain and metabolic disease. During early stages of development, the circadian system undergoes a critical period of adjustment, and it is especially vulnerable to altered lighting conditions that may program its function, leading to long-term effects. Read More

    Evidence of a diurnal rhythm in implicit reward learning.
    Chronobiol Int 2018 Apr 24:1-11. Epub 2018 Apr 24.
    a McLean Hospital & Harvard Medical School , Belmont , MA , USA.
    Many aspects of hedonic behavior, including self-administration of natural and drug rewards, as well as human positive affect, follow a diurnal cycle that peaks during the species-specific active period. This variation has been linked to circadian modulation of the mesolimbic dopamine system, and is hypothesized to serve an adaptive function by driving an organism to engage with the environment during times where the opportunity for obtaining rewards is high. However, relatively little is known about whether more complex facets of hedonic behavior - in particular, reward learning - follow the same diurnal cycle. Read More

    Impairment of sleep quality and quality of life in bimodal chronotype individuals.
    Chronobiol Int 2018 Apr 24:1-6. Epub 2018 Apr 24.
    a Physiology , Universidade Federal do Parana Setor de Ciencias Biologicas , Curitiba , Brazil.
    There is still insufficient data about the characteristics and clinical significance of the bimodal chronotype. We evaluated more than 1000 students with Morningness-Eveningness Questionnaire, Munich Chronotype Questionnaire (MCTQ), Pittsburgh Sleep Quality Index and 36-item Short Form Health Survey. Twelve percent of the sample was bimodal and they showed similar results to intermediate chronotype in MCTQ-chronotype and social jetlag, both different from morning and evening chronotypes. Read More

    Factor structure of the Brazilian version of Pediatric Daytime Sleepiness Scale.
    Chronobiol Int 2018 Apr 24:1-7. Epub 2018 Apr 24.
    a Center of Physical Activity and Health Research, Santa Catarina State University (UDESC) , Florianópolis , SC , Brazil.
    The present study aimed to analyze the construct validity of the Pediatric Daytime Sleepiness Scale (PDSS) for the evaluation of the daytime sleepiness construct in adolescents through confirmatory factorial analysis. The cross-sectional study was carried out with a sample of 773 adolescents aged 14 to 19 years, enrolled in the state schools of Paranaguá, Paraná, Brazil. We investigated the sex, age, school year, study shift, occupational status, socioeconomic level and daytime sleepiness. Read More

    Diet-induced obesity reduces core body temperature across the estrous cycle and pregnancy in the rat.
    Chronobiol Int 2018 Apr 16:1-11. Epub 2018 Apr 16.
    a School of Human Sciences , The University of Western Australia , Perth , Australia.
    Obesity during pregnancy causes adverse maternal and fetal health outcomes and programs offspring for adult-onset diseases, including cardiovascular disease. Obesity also disrupts core body temperature (T) regulation in nonpregnant rodents; however, it is unknown whether obesity alters normal maternal T adaptations to pregnancy. Since T is influenced by the circadian system, and both obesity and pregnancy alter circadian biology, it was hypothesized that obesity disrupts the normal rhythmic patterns of T before and during gestation. Read More

    Late chronotype and high social jetlag are associated with burnout in evening-shift workers: Assessment using the Chinese-version MCTQ.
    Chronobiol Int 2018 Apr 16:1-10. Epub 2018 Apr 16.
    c Department of Respiratory Therapy , College of Health Care, China Medical University , Taichung , Taiwan.
    Chronotypes are associated with shift work tolerance and sleep in shift workers, and sleep mediates the impact of shift work on mental health. However, the role of chronotype in the association between shift work and mental health has not been clarified. In this study, we aimed to examine the association between chronotype and burnout in shift workers, using the validated Munich ChronoType Questionnaire for shift workers (MCTQ). Read More

    Effect of bright light therapy on delayed sleep/wake cycle and reaction time of athletes participating in the Rio 2016 Olympic Games.
    Chronobiol Int 2018 Apr 16:1-9. Epub 2018 Apr 16.
    a Departamento de Esportes, Escola de Educação Física, Fisioterapia e Terapia Ocupacional , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
    This study investigated the effect of using an artificial bright light on the entrainment of the sleep/wake cycle as well as the reaction times of athletes before the Rio 2016 Olympic Games. A total of 22 athletes from the Brazilian Olympic Swimming Team were evaluated, with the aim of preparing them to compete at a time when they would normally be about to go to bed for the night. During the 8-day acclimatization period, their sleep/wake cycles were assessed by actigraphy, with all the athletes being treated with artificial light therapy for between 30 and 45 min (starting at day 3). Read More

    Evening types demonstrate reduced SSRI treatment efficacy.
    Chronobiol Int 2018 Apr 16:1-4. Epub 2018 Apr 16.
    a Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University , Melbourne , VIC , Australia.
    Selective serotonin reuptake inhibitors (SSRIs) have a profound effect on the circadian system's response to environmental light, which may impact treatment outcomes for patients depending on their habitual light exposure patterns. Here, we investigated the relationship between time-of-day preference, depressive symptoms and self-reported antidepressant treatment response. Evening types reported having taken a higher number of antidepressant medications in the previous 5 years and lower SSRI efficacy than morning types. Read More

    Associations between chronotype, morbidity and mortality in the UK Biobank cohort.
    Chronobiol Int 2018 Apr 11:1-9. Epub 2018 Apr 11.
    b Faculty of Health and Medical Sciences , University of Surrey , Surrey , UK.
    Later chronotype (i.e. evening preference) and later timing of sleep have been associated with greater morbidity, including higher rates of metabolic dysfunction and cardiovascular disease (CVD). Read More

    Vitamin D supply in shift working nurses.
    Chronobiol Int 2018 May 11;35(5):724-729. Epub 2018 Apr 11.
    a Center for Epidemiology, Institute for Prevention and Occupational Medicine of the German Social Accident Insurance , Institute of the Ruhr-Universität Bochum (IPA) , Bochum , Germany.
    We studied determinants of Vitamin D in serum of 67 female health care workers (aged 25-60 years), including age, body mass index, physical activity, and shift work. Overall, vitamin D levels were low, ranging from 6 to 51 ng/mL (median: 20 ng/mL). Lower serum levels were found in samples drawn in winter and spring and in obese subjects. Read More

    Association of the melatonin circadian rhythms with clock 3111T/C gene polymorphism in Caucasian and Asian menopausal women with insomnia.
    Chronobiol Int 2018 Apr 5:1-11. Epub 2018 Apr 5.
    a Scientific Centre for Family Health and Human Reproduction Problems , Federal State Public Scientific Institution , Irkutsk , Russian Federation.
    A comparative analysis of melatonin circadian rhythms in Caucasian (incoming population) and Asian (indigenous population) menopausal women with/without sleep disorders depending on the genotype of Clock 3111T/C gene polymorphism was realized.The melatonin level in the saliva was determined four times a day (6:00-7:00, 12:00-13:00, 18:00-19:00, 23:00-00:00 h). The Caucasian women-carriers of the TT-genotype with insomnia as compared to control group-had a higher morning melatonin level and a lower night melatonin level. Read More

    Exploring the effect of chronotype on hippocampal volume and shape: A combined approach.
    Chronobiol Int 2018 Apr 5:1-7. Epub 2018 Apr 5.
    a Department of Psychology , University of Roehampton , London , UK.
    Current evidence suggests that acute depression is associated with reduced total hippocampal volume and regional atrophy. Here, using structural magnetic resonance imaging, we assayed linear effects of chronotype on total hippocampal volume and morphology. Later chronotype was associated with localised atrophy in the subiculum region of the right hippocampus in the absence of changes in total volume. Read More

    Dstac is required for normal circadian activity rhythms in Drosophila.
    Chronobiol Int 2018 Apr 5:1-11. Epub 2018 Apr 5.
    a Department of Molecular, Cellular and Developmental Biology , University of Michigan , Ann Arbor , MI , USA.
    The genetic, molecular and neuronal mechanism underlying circadian activity rhythms is well characterized in the brain of Drosophila. The small ventrolateral neurons (s-LNs) and pigment dispersing factor (PDF) expressed by them are especially important for regulating circadian locomotion. Here we describe a novel gene, Dstac, which is similar to the stac genes found in vertebrates that encode adaptor proteins, which bind and regulate L-type voltage-gated Ca channels (CaChs). Read More

    A longitudinal large-scale objective sleep data analysis revealed a seasonal sleep variation in the Japanese population.
    Chronobiol Int 2018 Mar 28:1-13. Epub 2018 Mar 28.
    a Graduate School of Pharmaceutical Sciences , Nagoya City University , Nagoya , Japan.
    In the contemporary era, when life habits are largely determined by social needs and individual preferences, sleep is nevertheless affected by seasonal environmental changes. Japan has large seasonal and geographical alterations of photoperiod and climate. Japan does not adopt the daylight saving time (DST) system, making it a suitable country for the study of seasonal variations in natural human sleep. Read More

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