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Author Arendt, J. url  doi
openurl 
  Title Biological rhythms during residence in polar regions Type Journal Article
  Year 2012 Publication Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 29 Issue 4 Pages 379-394  
  Keywords *Acclimatization; Activities of Daily Living; Affect; Antarctic Regions; Arctic Regions; *Biological Clocks; *Circadian Rhythm; *Cold Climate; *Cold Temperature; Energy Metabolism; Feeding Behavior; Humans; Melatonin/metabolism; Personnel Staffing and Scheduling; *Photoperiod; Seasonal Affective Disorder/physiopathology/prevention & control/psychology; *Seasons; Sleep; Sleep Disorders, Circadian Rhythm/etiology/physiopathology/*prevention & control/psychology; Time Factors; Workload; Workplace  
  Abstract At Arctic and Antarctic latitudes, personnel are deprived of natural sunlight in winter and have continuous daylight in summer: light of sufficient intensity and suitable spectral composition is the main factor that maintains the 24-h period of human circadian rhythms. Thus, the status of the circadian system is of interest. Moreover, the relatively controlled artificial light conditions in winter are conducive to experimentation with different types of light treatment. The hormone melatonin and/or its metabolite 6-sulfatoxymelatonin (aMT6s) provide probably the best index of circadian (and seasonal) timing. A frequent observation has been a delay of the circadian system in winter. A skeleton photoperiod (2 x 1-h, bright white light, morning and evening) can restore summer timing. A single 1-h pulse of light in the morning may be sufficient. A few people desynchronize from the 24-h day (free-run) and show their intrinsic circadian period, usually >24 h. With regard to general health in polar regions, intermittent reports describe abnormalities in various physiological processes from the point of view of daily and seasonal rhythms, but positive health outcomes are also published. True winter depression (SAD) appears to be rare, although subsyndromal SAD is reported. Probably of most concern are the numerous reports of sleep problems. These have prompted investigations of the underlying mechanisms and treatment interventions. A delay of the circadian system with “normal” working hours implies sleep is attempted at a suboptimal phase. Decrements in sleep efficiency, latency, duration, and quality are also seen in winter. Increasing the intensity of ambient light exposure throughout the day advanced circadian phase and was associated with benefits for sleep: blue-enriched light was slightly more effective than standard white light. Effects on performance remain to be fully investigated. At 75 degrees S, base personnel adapt the circadian system to night work within a week, in contrast to temperate zones where complete adaptation rarely occurs. A similar situation occurs on high-latitude North Sea oil installations, especially when working 18:00-06:00 h. Lack of conflicting light exposure (and “social obligations”) is the probable explanation. Many have problems returning to day work, showing circadian desynchrony. Timed light treatment again has helped to restore normal phase/sleep in a small number of people. Postprandial response to meals is compromised during periods of desynchrony with evidence of insulin resistance and elevated triglycerides, risk factors for heart disease. Only small numbers of subjects have been studied intensively in polar regions; however, these observations suggest that suboptimal light conditions are deleterious to health. They apply equally to people living in temperate zones with insufficient light exposure.  
  Address Centre for Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK. arendtjo@gmail.com  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22497433; PMCID:PMC3793275 Approved no  
  Call Number IDA @ john @ Serial 143  
Permanent link to this record
 

 
Author Arendt, J.; Middleton, B. url  doi
openurl 
  Title Human seasonal and circadian studies in Antarctica (Halley, 75 degrees S) Type Journal Article
  Year 2018 Publication General and Comparative Endocrinology Abbreviated Journal Gen Comp Endocrinol  
  Volume 258 Issue Pages 250-258  
  Keywords Human Activities; Acclimatization/*physiology; Actigraphy; Adult; Antarctic Regions; Behavior/*physiology; Circadian Rhythm/*physiology; Darkness; Female; Heart Rate/physiology; Humans; Libido; Light; Male; Melatonin/blood; Photoperiod; *Seasons; Sleep/physiology; Young Adult; *Antarctica; *Circadian; *Light; *Melatonin; *Seasonal  
  Abstract Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75 degrees S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species. The neuroendocrine signal providing photoperiodic information to body physiology is the duration of melatonin secretion which reflects the length of the night: longer in the short days of winter and shorter in summer. Light of sufficient intensity and spectral composition serves to suppress production of melatonin and to set the circadian timing and the duration of the rhythm. In humans early observations suggested that bright (>2000 lux) white light was needed to suppress melatonin completely. Shortly thereafter winter depression (Seasonal Affective Disorder or SAD) was described, and its successful treatment by an artificial summer photoperiod of bright white light, sufficient to shorten melatonin production. At Halley dim artificial light intensity during winter was measured, until 2003, at a maximum of approximately 500 lux in winter. Thus a strong seasonal and circadian time cue was absent. It seemed likely that winter depression would be common in the extended period of winter darkness and could be treated with an artificial summer photoperiod. These observations, and predictions, inspired a long series of studies regarding human seasonal and circadian status, and the effects of light treatment, in a small overwintering, isolated community, living in the same conditions for many months at Halley. We found little evidence of SAD, or change in duration of melatonin production with season. However the timing of the melatonin rhythm itself, and/or that of its metabolite 6-sulphatoxymelatonin (aMT6s), was used as a primary marker of seasonal, circadian and treatment changes. A substantial phase delay of melatonin in winter was advanced to summer phase by a two pulse 'skeleton' bright white light treatment. Subsequently a single morning pulse of bright white light was effective with regard to circadian phase and improved daytime performance. The circadian delay evidenced by melatonin was accompanied by delayed sleep (logs and actigraphy): poor sleep is a common complaint in Polar regions. Appropriate extra artificial light, both standard white, and blue enriched, present throughout the day, effectively countered delay in sleep timing and the aMT6s rhythm. The most important factor appeared to be the maximum light experienced. Another manifestation of the winter was a decline in self-rated libido (men only on base at this time). Women on the base showed lower aspects of physical and mental health compared to men. Free-running rhythms were seen in some subjects following night shift, but were rarely found at other times, probably because this base has strongly scheduled activity and leisure time. Complete circadian adaptation during a week of night shift, also seen in a similar situation on North Sea oil rigs, led to problems readapting back to day shift in winter, compared to summer. Here again timed light treatment was used to address the problem. Sleep, alertness and waking performance are critically dependent on optimum circadian phase. Circadian desynchrony is associated with increased risk of major disease in shift workers. These studies provide some groundwork for countering/avoiding circadian desynchrony in rather extreme conditions.  
  Address Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK. Electronic address: b.middleton@surrey.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0016-6480 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:28526480 Approved no  
  Call Number IDA @ john @ Serial 2248  
Permanent link to this record
 

 
Author 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  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18786384 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 752  
Permanent link to this record
 

 
Author Kanikowska, D.; Sugenoya, J.; Sato, M.; Shimizu, Y.; Inukai, Y.; Nishimura, N.; Iwase, S. url  doi
openurl 
  Title Seasonal variation in blood concentrations of interleukin-6, adrenocorticotrophic hormone, metabolites of catecholamine and cortisol in healthy volunteers Type Journal Article
  Year 2009 Publication International Journal of Biometeorology Abbreviated Journal Int J Biometeorol  
  Volume 53 Issue 6 Pages 479-485  
  Keywords Human Health; Adrenocorticotropic Hormone/*blood; Catecholamines/*blood; Circadian Rhythm/*physiology; Humans; Hydrocortisone/*blood; Interleukin-6/*blood; Male; Reference Values; *Seasons; Young Adult  
  Abstract We investigated seasonal changes in blood concentrations of interleukin-6 (IL-6), adrenocorticotrophic hormone (ACTH), metabolites of catecholamine (VMA, HVA, and 5-HIAA) and cortisol in humans. Eight volunteers were investigated at four times during the year (February, May, August and October) at latitude 35 degrees N. The mean ambient temperature at the collection periods was higher in the order of summer > autumn approximately spring > winter. Changes in mood were also monitored by a profile of mood states (POMS) questionnaire. The concentration of IL-6 was significantly higher in winter and summer than in spring and autumn. The concentrations of ACTH, HVA and VMA were significantly higher in summer. No seasonal variation was detected in cortisol. There were significant differences among the seasons in subscale tension and anger in the POMS questionnaire; the tension subscale showed significant differences between spring and autumn, with a higher score in spring. The results demonstrate that Il-6, ACTH, HVA and VMA exhibit statistically significant seasonal rhythms, which might have important diagnostic and therapeutic implications.  
  Address Department of Physiology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan. dkanikowska@hotmail.com  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0020-7128 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19506914 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 768  
Permanent link to this record
 

 
Author Kyba, C.C.M.; Ruhtz, T.; Fischer, J.; Hölker, F. url  doi
openurl 
  Title Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems Type Journal Article
  Year 2011 Publication PloS one Abbreviated Journal PLoS One  
  Volume 6 Issue 3 Pages e17307  
  Keywords Berlin; *Cities; *Ecosystem; Environmental Pollution/*adverse effects/analysis; *Light; Seasons; *Weather  
  Abstract The diurnal cycle of light and dark is one of the strongest environmental factors for life on Earth. Many species in both terrestrial and aquatic ecosystems use the level of ambient light to regulate their metabolism, growth, and behavior. The sky glow caused by artificial lighting from urban areas disrupts this natural cycle, and has been shown to impact the behavior of organisms, even many kilometers away from the light sources. It could be hypothesized that factors that increase the luminance of the sky amplify the degree of this “ecological light pollution”. We show that cloud coverage dramatically amplifies the sky luminance, by a factor of 10.1 for one location inside of Berlin and by a factor of 2.8 at 32 km from the city center. We also show that inside of the city overcast nights are brighter than clear rural moonlit nights, by a factor of 4.1. These results have important implications for choronobiological and chronoecological studies in urban areas, where this amplification effect has previously not been considered.  
  Address Institute for Space Sciences, Freie Universitat Berlin, Berlin, Germany. christopher.kyba@wew.fu-berlin.de  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21399694; PMCID:PMC3047560 Approved no  
  Call Number IDA @ john @ Serial 20  
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