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Author (up) Foster, R.G.; Roenneberg, T. url  doi
openurl 
  Title Human responses to the geophysical daily, annual and lunar cycles Type Journal Article
  Year 2008 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 18 Issue 17 Pages R784-R794  
  Keywords Human Health; Biological Clocks; Birth Rate; Circadian Rhythm; Death; Female; Human Activities; Humans; Male; Moon; *Periodicity; Photoperiod; Seasons; Sexual Behavior; Sleep  
  Abstract Collectively the daily, seasonal, lunar and tidal geophysical cycles regulate much of the temporal biology of life on Earth. The increasing isolation of human societies from these geophysical cycles, as a result of improved living conditions, high-quality nutrition and 24/7 working practices, have led many to believe that human biology functions independently of them. Yet recent studies have highlighted the dominant role that our circadian clock plays in the organisation of 24 hour patterns of behaviour and physiology. Preferred wake and sleep times are to a large extent driven by an endogenous temporal program that uses sunlight as an entraining cue. The alarm clock can drive human activity rhythms but has little direct effect on our endogenous 24 hour physiology. In many situations, our biology and our society appear to be in serious opposition, and the damaging consequences to our health under these circumstances are increasingly recognised. The seasons dominate the lives of non-equatorial species, and until recently, they also had a marked influence on much of human biology. Despite human isolation from seasonal changes in temperature, food and photoperiod in the industrialised nations, the seasons still appear to have a small, but significant, impact upon when individuals are born and many aspects of health. The seasonal changes that modulate our biology, and how these factors might interact with the social and metabolic status of the individual to drive seasonal effects, are still poorly understood. Lunar cycles had, and continue to have, an influence upon human culture, though despite a persistent belief that our mental health and other behaviours are modulated by the phase of the moon, there is no solid evidence that human biology is in any way regulated by the lunar cycle.  
  Address Circadian and Visual Neuroscience, Nuffield Laboratory of Ophthalmology, University of Oxford, Levels 5 & 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 7BN, UK. russell.foster@eye.ox.ac.uk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18786384 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 752  
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Author (up) Kantermann, T.; Roenneberg, T. url  doi
openurl 
  Title Is light-at-night a health risk factor or a health risk predictor? Type Journal Article
  Year 2009 Publication Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 26 Issue 6 Pages 1069-1074  
  Keywords *Chronobiology Disorders; Circadian Rhythm; Environmental Exposure; Humans; *Light; Neoplasms; Risk Factors  
  Abstract In 2007, the IARC (WHO) has classified “shift-work that involves circadian disruption” as potentially carcinogenic. Ample evidence leaves no doubt that shift-work is detrimental for health, but the mechanisms behind this effect are not well understood. The hormone melatonin is often considered to be a causal link between night shift and tumor development. The underlying “light-at-night” (LAN) hypothesis is based on the following chain of arguments: melatonin is a hormone produced under the control of the circadian clock at night, and its synthesis can be suppressed by light; as an indolamine, it potentially acts as a scavenger of oxygen radicals, which in turn can damage DNA, which in turn can cause cancer. Although there is no experimental evidence that LAN is at the basis of increased cancer rates in shiftworkers, the scenario “light at night can cause cancer” influences research, medicine, the lighting industry and (via the media) also the general public, well beyond shiftwork. It is even suggested that baby-lights, TVs, computers, streetlights, moonlight, emergency lights, or any so-called “light pollution” by urban developments cause cancer via the mechanisms proposed by the LAN hypothesis. Our commentary addresses the growing concern surrounding light pollution. We revisit the arguments of the LAN theory and put them into perspective regarding circadian physiology, physical likelihood (e.g., what intensities reach the retina), and potential risks, specifically in non-shiftworkers.  
  Address Institute for Medical Psychology, University of Munich LMU, Munich, Germany  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19731106 Approved no  
  Call Number IDA @ john @ Serial 134  
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Author (up) Pilz, L.K.; Levandovski, R.; Oliveira, M.A.B.; Hidalgo, M.P.; Roenneberg, T. url  doi
openurl 
  Title Sleep and light exposure across different levels of urbanisation in Brazilian communities Type Journal Article
  Year 2018 Publication Scientific Reports Abbreviated Journal Sci Rep  
  Volume 8 Issue 1 Pages 11389  
  Keywords Human Health; Sleep  
  Abstract Quilombos are settlements originally founded by Africans and African descendants (Quilombolas) in remote parts of Brazil to escape slavery. Due to individual histories, Quilombos nowadays exhibit different states of industrialisation, making them ideal for studying the influence of electrification on daily behaviour. In a comparative approach, we aimed to understand whether and how human sleep changes with the introduction of artificial light. We investigated daily rest-activity-rhythms and sleep-patterns in the Quilombolas' by both wrist actimetry and the Munich ChronoType Questionnaire (MCTQ; the results of these two instruments correlated highly). Seven communities (MCTQ: N = 213/actimetry: N = 125) were compared in this study. Light exposure, phase of activity, sleep timing and duration differ across communities with various levels of urbanisation and histories of access to electricity. People living without electricity and those, who acquired it only very recently on average sleep earlier than those in more urbanised communities (mid-sleep about 1 hour earlier); sleep duration tends to be longer. Our results and those of others show that use of electricity and modern lifestyles have changed sleep behaviour. To understand the consequences of these changes for health, further studies are warranted.  
  Address Visiting Professor at UFRGS/CAPES, Porto Alegre, RS, Brazil. roenneberg@lmu.de  
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  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Medium  
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  Notes PMID:30061685 Approved no  
  Call Number GFZ @ kyba @ Serial 1968  
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Author (up) Porcheret, K.; Wald, L.; Fritschi, L.; Gerkema, M.; Gordijn, M.; Merrrow, M.; Rajaratnam, S.M.W.; Rock, D.; Sletten, T.L.; Warman, G.; Wulff, K.; Roenneberg, T.; Foster, R.G. url  doi
openurl 
  Title Chronotype and environmental light exposure in a student population Type Journal Article
  Year 2018 Publication Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 35 Issue 10 Pages 1365-1374  
  Keywords Human Health  
  Abstract 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. morning, intermediate or evening type. The aim of this study was to investigate the associations between environmental light exposure, due to geographical location, on the chronotype of university students. Over 6 000 university students from cities in the Northern Hemisphere (Oxford, Munich and Groningen) and Southern Hemisphere (Perth, Melbourne and Auckland) completed the Munich ChronoType Questionnaire. In parallel, light measures (daily irradiance, timing of sunrise and sunset) were compiled from satellite or ground stations at each of these locations. Our data shows that later mid-sleep point on free days (corrected for oversleep on weekends MFSsc) is associated with (i) residing further from the equator, (ii) a later sunset, (iii) spending more time outside and (iv) waking from sleep significantly after sunrise. However, surprisingly, MSFsc did not correlate with daily light intensity at the different geographical locations. Although these findings appear to contradict earlier studies suggesting that in the wider population increased light exposure is associated with an earlier chronotype, our findings are derived exclusively from a student population aged between 17 and 26 years. We therefore suggest that the age and occupation of our population increase the likelihood that these individuals will experience relatively little light exposure in the morning whilst encountering more light exposure later in the day, when light has a delaying effect upon the circadian system.  
  Address a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK  
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  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29913073 Approved no  
  Call Number GFZ @ kyba @ Serial 1962  
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Author (up) Roenneberg, T. url  openurl
  Title Wie wir ticken. Die Bedeutung der inneren Uhr für unser Leben Type Journal Article
  Year 2010 Publication Abbreviated Journal  
  Volume Issue Pages 240  
  Keywords Human Health  
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  Notes Approved no  
  Call Number LoNNe @ kagoburian @ Serial 844  
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Author (up) Roenneberg, T.; Foster, R.G. url  doi
openurl 
  Title Twilight Times: Light and the Circadian System Type Journal Article
  Year 1997 Publication Photochemistry and Photobiology Abbreviated Journal Photochem Photobiol  
  Volume 66 Issue 5 Pages 549-561  
  Keywords Human Health  
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  Series Volume Series Issue Edition  
  ISSN 0031-8655 ISBN Medium  
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  Notes Approved no  
  Call Number LoNNe @ kagoburian @ Serial 800  
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Author (up) Roenneberg, T.; Merrow, M. url  openurl
  Title Circadian clocks – from genes to complex behaviour Type Journal Article
  Year 1999 Publication Reproduction Nutrition Development Abbreviated Journal  
  Volume 39 Issue 39 Pages 3  
  Keywords Human Health  
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  Notes Approved no  
  Call Number LoNNe @ kagoburian @ Serial 799  
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Author (up) Van Dycke, K.C.G.; Rodenburg, W.; van Oostrom, C.T.M.; van Kerkhof, L.W.M.; Pennings, J.L.A.; Roenneberg, T.; van Steeg, H.; van der Horst, G.T.J. url  doi
openurl 
  Title Chronically Alternating Light Cycles Increase Breast Cancer Risk in Mice Type Journal Article
  Year 2015 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 25 Issue 14 Pages 1932-1937  
  Keywords Animals  
  Abstract Although epidemiological studies in shift workers and flight attendants have associated chronic circadian rhythm disturbance (CRD) with increased breast cancer risk, causal evidence for this association is lacking [1, 2]. Several scenarios have been proposed to contribute to the shift work-cancer connection: (1) internal desynchronization, (2) light at night (resulting in melatonin suppression), (3) sleep disruption, (4) lifestyle disturbances, and (5) decreased vitamin D levels due to lack of sunlight [3]. The confounders inherent in human field studies are less problematic in animal studies, which are therefore a good approach to assess the causal relation between circadian disturbance and cancer. However, the experimental conditions of many of these animal studies were far from the reality of human shift workers. For example, some involved xenografts (addressing tumor growth rather than cancer initiation and/or progression) [4, 5], chemically induced tumor models [6, 7], or continuous bright light exposure, which can lead to suppression of circadian rhythmicity [8, 9]. Here, we have exposed breast cancer-prone p53(R270H(c)/+)WAPCre conditional mutant mice (in a FVB genetic background) to chronic CRD by subjecting them to a weekly alternating light-dark (LD) cycle throughout their life. Animals exposed to the weekly LD inversions showed a decrease in tumor suppression. In addition, these animals showed an increase in body weight. Importantly, this study provides the first experimental proof that CRD increases breast cancer development. Finally, our data suggest internal desynchronization and sleep disturbance as mechanisms linking shift work with cancer development and obesity.  
  Address Department of Genetics, Center for Biomedical Genetics, Erasmus University Medical Center, Rotterdam 3000 CA, the Netherlands. Electronic address: g.vanderhorst@erasmusmc.nl  
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  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
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  Notes PMID:26196479 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 1221  
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Author (up) Vetter, C.; Juda, M.; Lang, D.; Wojtysiak, A.; Roenneberg, T. url  openurl
  Title Blue-enriched office light competes with natural light as a zeitgeber Type Journal Article
  Year 2011 Publication Scandinavian Journal of Work, Environment & Health Abbreviated Journal Scand J Work Environ Health  
  Volume 37 Issue 5 Pages 437-445  
  Keywords *Circadian Rhythm; *Color; Humans; *Lighting; *Occupational Health; Sleep; Wakefulness; blue light; circadian disruption; Circadian rhythm; sleep  
  Abstract OBJECTIVES: Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the “zeitgeber” light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. METHODS: An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. RESULTS: Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. CONCLUSION: The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.  
  Address Institute for Medical Psychology, Centre of Chronobiology, Ludwig-Maximilians-Universitat, Munich, Germany  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0355-3140 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21246176 Approved no  
  Call Number IDA @ john @ Serial 350  
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