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Author (up) Obayashi, K.; Saeki, K.; Iwamoto, J.; Ikada, Y.; Kurumatani, N.
Title Association between light exposure at night and nighttime blood pressure in the elderly independent of nocturnal urinary melatonin excretion Type Journal Article
Year 2014 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 31 Issue 6 Pages 779-786
Keywords Actigraphy; circadian rhythm; elderly; light at night; melatonin; nighttime blood pressure; geriatrics
Abstract Circadian misalignment between internal and environmental rhythms dysregulates blood pressure (BP) variability because of disruption of the biological clock, resulting in increased nighttime BP. Although exposure to light-at-night is associated with the circadian misalignment, it remains unclear whether exposure to light-at-night in home settings is associated with nighttime BP. In this cross-sectional analysis of 528 elderly individuals (mean age: 72.8 years), we measured bedroom light intensity at 1-min intervals on two consecutive nights along with ambulatory BP, overnight urinary melatonin excretion and actigraphy. With regard to adjusted mean comparisons using analysis of covariance, the light-at-night group (average: >/=5 lux; n = 109) showed significantly higher nighttime systolic BP (SBP; adjusted mean: 120.8 vs. 116.5 mmHg, p = 0.01) and diastolic BP (70.1 vs. 67.1 mmHg, p < 0.01) compared with the Darker group (average: <5 lux; n = 419) independently of potential confounding factors including overnight urinary melatonin excretion and actigraphic sleep quality. We observed consistent associations between light-at-night and nighttime BP in different cutoff values for light-at-night intensity (i.e. 3 and 10 lux). In conclusion, exposure to light-at-night in home settings is significantly associated with increased nighttime BP in elderly individuals independently of overnight urinary melatonin excretion. A 4.3 mmHg increase in nighttime SBP is associated with a 6.1% increase in total mortality, which corresponds to approximately 10 000 annual excess deaths in Japanese elderly population.
Address Department of Community Health and Epidemiology, Nara Medical University School of Medicine , Nara , Japan
Corporate Author Thesis
Publisher Informa Plc 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:24673296 Approved no
Call Number IDA @ john @ Serial 315
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Author (up) Rumanova, V.S.; Okuliarova, M.; Molcan, L.; Sutovska, H.; Zeman, M.
Title Consequences of low-intensity light at night on cardiovascular and metabolic parameters in spontaneously hypertensive rats (1) Type Journal Article
Year 2019 Publication Canadian Journal of Physiology and Pharmacology Abbreviated Journal Can J Physiol Pharmacol
Volume 97 Issue 9 Pages 863-871
Keywords Animals; Ppar; blood pressure; circadian; circadien; insulin resistance; metabolism; metabolisme; recepteurs actives par les proliferateurs de peroxysomes; resistance a l'insuline; tension arterielle
Abstract Circadian rhythms are an inherent property of physiological processes and can be disturbed by irregular environmental cycles, including artificial light at night (ALAN). Circadian disruption may contribute to many pathologies, such as hypertension, obesity, and type 2 diabetes, but the underlying mechanisms are not understood. Our study investigated the consequences of ALAN on cardiovascular and metabolic parameters in spontaneously hypertensive rats, which represent an animal model of essential hypertension and insulin resistance. Adult males were exposed to a 12 h light – 12 h dark cycle and the ALAN group experienced dim light at night (1-2 lx), either for 2 or 5 weeks. Rats on ALAN showed a loss of light-dark variability for systolic blood pressure, but not for heart rate. Moreover, a gradual increase of systolic blood pressure was recorded over 5 weeks of ALAN. Exposure to ALAN increased plasma insulin and hepatic triglyceride levels. An increased expression of metabolic transcription factors, Pparalpha and Ppargamma, in the epididymal fat and a decreased expression of Glut4 in the heart was found in the ALAN group. Our results demonstrate that low-intensity ALAN can disturb blood pressure control and augment insulin resistance in spontaneously hypertensive rats, and may represent a serious risk factor for cardiometabolic diseases.
Address Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
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 0008-4212 ISBN Medium
Area Expedition Conference
Notes PMID:31251886 Approved no
Call Number GFZ @ kyba @ Serial 2811
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Author (up) Stern, M.; Broja, M.; Sansone, R.; Grone, M.; Skene, S.S.; Liebmann, J.; Suschek, C.V.; Born, M.; Kelm, M.; Heiss, C.
Title Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans Type Journal Article
Year 2018 Publication European Journal of Preventive Cardiology Abbreviated Journal Eur J Prev Cardiol
Volume 25 Issue 17 Pages 1875-1883
Keywords Human Health; Blue light; blood pressure; endothelial function; forearm blood flow; pulse wave velocity
Abstract AIMS: Previous studies have shown that ultraviolet light can lead to the release of nitric oxide from the skin and decrease blood pressure. In contrast to visible light the local application of ultraviolet light bears a cancerogenic risk. Here, we investigated whether whole body exposure to visible blue light can also decrease blood pressure and increase endothelial function in healthy subjects. METHODS: In a randomised crossover study, 14 healthy male subjects were exposed on 2 days to monochromatic blue light or blue light with a filter foil (control light) over 30 minutes. We measured blood pressure (primary endpoint), heart rate, forearm vascular resistance, forearm blood flow, endothelial function (flow-mediated dilation), pulse wave velocity and plasma nitric oxide species, nitrite and nitroso compounds (secondary endpoints) during and up to 2 hours after exposure. RESULTS: Blue light exposure significantly decreased systolic blood pressure and increased heart rate as compared to control. In parallel, blue light significantly increased forearm blood flow, flow-mediated dilation, circulating nitric oxide species and nitroso compounds while it decreased forearm vascular resistance and pulse wave velocity. CONCLUSION: Whole body irradiation with visible blue light at real world doses improves blood pressure, endothelial function and arterial stiffness by nitric oxide released from photolabile intracutanous nitric oxide metabolites into circulating blood.
Address Department of Clinical and Experimental Medicine, Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford GU2 7XH, UK. Email: c.heiss(at)
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2047-4873 ISBN Medium
Area Expedition Conference
Notes PMID:30196723 Approved no
Call Number IDA @ john @ Serial 2157
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