scholarly journals Bright Light Therapy’s Effect on Night Shift Health Care Workers Who Suffer from Light Induced Misalignment of Circadian Rhythms

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mackenzie Peed
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Cell Cycle Progression ◽  
Clock Genes ◽  
Light Exposure ◽  
Night Shift ◽  
Hormone Secretion ◽  
Bright Light ◽  
The United States ◽  
Sleep Cycle

Modern-day society is based on a high pace lifestyle that people are constantly attempting to keep up with. The invention of the light completely changed society, allowing people to work outside of daylight hours. As countries become more and more industrialized, the need for 24/7 productivity becomes more and more common. From transportation to mining to medicine, individuals willing to work unconventional hours are necessary for the sustainability of the industry. This group of people, working outside “normal” work hours such as between 7 a.m. and 6 p.m. or shifts longer than eight hours, are known as shift workers. They make up about 26.5 million people in the employed population in the United States and about 100 million around the world (Moore-Ede & Platika, 2018). Shift work affects a person’s circadian rhythm, causing issues. “Circadian rhythm mainly controls the daily wake and sleep cycle and regulates physiological processes including hormone secretion, body temperature, feeding behavior, cell cycle progression, and drug, glucose, and xenobiotic metabolism” (Khan et al., 2018, p.2). This circadian rhythm is controlled by the circadian clock and is regulated through clock genes. Light exposure greatly influences circadian rhythms and specifically affects the release of the hormone melatonin which activates specific receptors MTI and MT2 that mediate sleep-promoting effects.

Abstract P160: Non-invasive Method to Assess Human Circadian Rhythms

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Daian Chen ◽  
S Justin Thomas ◽  
David A Calhoun ◽  
David M Pollock ◽  
Jennifer S Pollock
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Salivary Cortisol ◽  
Metabolic Diseases ◽  
Clock Genes ◽  
Light Exposure ◽  
Rna Isolation ◽  
Buccal Cells ◽  
Non Invasive ◽  
Salivary Melatonin

Circadian rhythms are controlled by an endogenous time-keeping system oscillating approximately on a 24-h cycle under constant conditions. These rhythms depend on a network of interacting genes and proteins, including transcriptional activators such as CLOCK, NPAS2, and ARNTL (BMAL1), which induce transcription of the clock genes Period ( Per1 , Per2 , and Per3 ) and Cryptochrome ( Cry1 and Cry2 ). Human salivary cortisol and melatonin follow a clear circadian rhythm as well. Disruption of the circadian rhythm and sleep-wake cycles are considered risk factors for a variety of health problems, especially hypertension and other cardiovascular and metabolic diseases. Here we put together practical methods for assessing circadian rhythms in adult subjects conducted by each individual. This method is non-invasive, inexpensive and provides a predictive profile of an individual’s circadian rhythm related to clock-controlled gene expression in buccal cells, salivary cortisol, salivary melatonin, and subject’s activity or sleep. Subjects are instructed on how to obtain buccal cells using swabs (Whatman OmniSwab) from the inside of their cheeks and collect saliva using salivettes (Sarstedt) every 4 hours starting at 6am, for 2 consecutive days. Subjects also wear actigraphy watches (Phillips Respironics) during the 2 days, to record their activity, light exposure and estimates of sleep times. To monitor adherence to correct time point collections, each subject is given an electronic vial called eCAP (Information Mediary Corp) that records the exact time the container is opened to place samples once collected. We demonstrate feasibility to extract up to 150ng/μl of RNA (Ambion RNAqueous-Micro Total RNA Isolation Kit) from buccal cells swabs. Salivary melatonin and cortisol are measured by radioimmunoassay (Buhlmann Lab) with melatonin peak levels ranging from 14 to 23 pg/ml and cortisol peak levels ranging from 10 to 24 ng/ml. We suggest that buccal cell expression of clock-controlled genes, salivary melatonin, salivary cortisol, and actigraphy data are valuable in providing reliable assessment of human circadian rhythm profiles under a variety of conditions.

Nonphotic entrainment of the human circadian pacemaker

1998 ◽  
Vol 274 (4) ◽  
pp. R991-R996 ◽  
Author(s):  
Elizabeth B. Klerman ◽  
David W. Rimmer ◽  
Derk-Jan Dijk ◽  
Richard E. Kronauer ◽  
Joseph F. Rizzo ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Biological Clock ◽  
Bright Light ◽  
Circadian Pacemaker ◽  
Temperature Rhythms ◽  
Blind Individuals ◽  
Nonphotic Entrainment ◽  
Core Body

In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals “free run” even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

Etudes comparées des rythmes circadiens et reflet actimétrique du sommeil de sportifs et de sédentaires en poste régulier de nuit

2003 ◽  
Vol 28 (6) ◽  
pp. 831-887 ◽  
Author(s):  
Benoît Mauvieux ◽  
Laurent Gouthière ◽  
Bruno Sesboüe ◽  
Damien Davenne
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Sleep Quality ◽  
Shift Work ◽  
Physical Training ◽  
Night Shift ◽  
Circadian Variation ◽  
Night Work ◽  
Sedentary Subjects

The aim of this study was to show the resistance and persistence of the circadian rhythm of temperature (T°) and the sleep quality of athletic subjects and sedentary subjects engaged in night work, and attempt to explain the mechanisms that influence these differences. The effects of night work on biological rhythms have been studied extensively in the past few years. The contradictory situations for the night workers irrefutably affect their biological systems. Individuals with high amplitudes in their circadian rhythms have been found to be more tolerant to shift work and this results in a greater stability of circadian rhythms. This seems beneficial in coping with frequent rhythm disturbances. The physical training program seems to improve several mechanisms of the human biological system: amplitudes of circadian rhythms were increased and the circadian rhythm period was more resistant to an environment extreme (night work, shift work, sleep deprivation, or jet lag). To test this hypothesis, athletes and sedentary subjects who were engaged in regular night work were selected in the PSA Peugeot Citroën Automobiles Group in French Normandy country. The circadian rhythm of the T° for both groups was studied with a specific methodology and with extensive spectral analysis, especially the spectral elliptic inverse method. Study models of the rhythm of the T° were determined and the characteristic parameters were exposed. A complementary actigraphic study showed the physical training program's effects on the sleep quality. The results revealed a large stability in the rhythm of circadian variation of T° for the athletes: the amplitude was still large but for the sedentary subjects the amplitude of the T° decreased and it was difficult to adjust a period on the rhythm of T°. The stability and persistent quality of the athletes' circadian rhythm was confirmed. We observed that the actigraphic sleep was greater for athletes than for sedentary subjects, and the acrophase time for the athletes was later than for the sedentary subjects during the night shift. Key words: circadian rhythm of temperature, actimetry, sleep quality, exercise, night work, methodology of rhythms analysis

scholarly journals Chronic Corticosterone Disrupts the Circadian Rhythm of CRH Expression and M6a RNA Methylation in the Chicken Hypothalamus

2021 ◽  
Author(s):  
Yang Yang ◽  
Wanwan Han ◽  
Aijia Zhang ◽  
Mindie Zhao ◽  
Wei Cong ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Chronic Stress ◽  
Hpa Axis ◽  
Clock Genes ◽  
Diurnal Fluctuation ◽  
Opposite Pattern ◽  
Rna Methylation ◽  
Diurnal Patterns ◽  
M6a Rna Methylation

Abstract Corticotropin-releasing hormone (CRH), the major secretagogue of the hypothalamic-pituitary-adrenal (HPA) axis, is intricately intertwined with the clock genes to regulate the circadian rhythm of various body functions. N6-methyladenosine (m6A) RNA methylation is involved in the regulation of circadian rhythm, yet it remains unknown whether CRH expression and m6A modification oscillate with the clock genes in chicken hypothalamus and how the circadian rhythms change under chronic stress. Here, we show that chronic exposure to corticosterone (CORT) eliminated the diurnal patterns of plasma CORT and melatonin levels in the chicken. The circadian rhythms of clock genes in hippocampus, hypothalamus and pituitary are all disturbed to different extent in CORT-treated chickens. The most striking changes occur in hypothalamus in which the diurnal fluctuation of CRH mRNA is flattened, together with mRNA of other feeding-related neuropeptides. Interestingly, hypothalamic m6A level oscillates in an opposite pattern to CRH mRNA, with lowest m6A level after midnight (ZT18) corresponding to the peak of CRH mRNA before dawn (ZT22). CORT diminished the circadian rhythm of m6A methylation with significantly increased level at night. Further site-specific m6A analysis on 3’UTR of CRH mRNA indicates that higher m6A on 3’UTR of CRH mRNA coincides with lower CRH mRNA at night (ZT18 and ZT22). Our results indicate that chronic stress disrupts the circadian rhythms of CRH expression in hypothalamus, leading to dysfunction of HPA axis in the chicken. RNA m6A modification is involved in the regulation of circadian rhythms in chicken hypothalamus under both basal and chronic stress conditions.

Circadian rhythm of catecholamines, cortisol and prolactin is altered in patients with apallic syndrome in comparison with normal volunteers

1982 ◽  
Vol 101 (3) ◽  
pp. 428-435 ◽  
Author(s):  
Dieter Ratge ◽  
Ernst Knoll ◽  
Ulrich Diener ◽  
Alexander Hadjidimos ◽  
Hermann Wisser
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Emotional Reactions ◽  
Control Group ◽  
Motor Patterns ◽  
Apallic Syndrome ◽  
Controlled Processes ◽  
Episodic Nature

Abstract. Circadian rhythms of catecholamines, cortisol and prolactin were investigated in 4 healthy subjects and in 6 patients suffering from an apallic syndrome. The clinical picture of this syndrome is characterized by disturbed consciousness (coma vigile), suspension of the sleeping and waking rhythm, lack of emotional reactions and appearance of primitive motor patterns. With the exception of dopamine a pronounced circadian rhythm was found in the control group for all investigated parameters. Catecholamines and cortisol showed a good correlation in the temporal pattern of plasma concentrations and urinary excreted amounts. In all apallic patients the circadian rhythm of prolactin was abolished. Only in one patient a rhythm of catecholamines and in 2 patients a rhythm of cortisol was still detectable. The data may indicate that the episodic nature of hormone secretion was essentially unaffected by the apallic syndrome. These results are regarded as an indication that endogenous, centrally controlled processes participate in circadian rhythms.

scholarly journals Minireview: Entrainment of the Suprachiasmatic Clockwork in Diurnal and Nocturnal Mammals

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5648-5655 ◽  
Author(s):  
Etienne Challet
Keyword(s):  
Activity Pattern ◽  
Molecular Mechanisms ◽  
Clock Genes ◽  
Light Exposure ◽  
Hormone Secretion ◽  
Receptor Activation ◽  
Active Species ◽  
Voluntary Exercise ◽  
Nocturnal Species ◽  
Master Clock

Daily rhythmicity, including timing of wakefulness and hormone secretion, is mainly controlled by a master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN clockwork involves various clock genes, with specific temporal patterns of expression that are similar in nocturnal and diurnal species (e.g. the clock gene Per1 in the SCN peaks at midday in both categories). Timing of sensitivity to light is roughly similar, during nighttime, in diurnal and nocturnal species. Molecular mechanisms of photic resetting are also comparable in both species categories. By contrast, in animals housed in constant light, exposure to darkness can reset the SCN clock, mostly during the resting period, i.e. at opposite circadian times between diurnal and nocturnal species. Nonphotic stimuli, such as scheduled voluntary exercise, food shortage, exogenous melatonin, or serotonergic receptor activation, are also capable of shifting the master clock and/or modulating photic synchronization. Comparison between day- and night-active species allows classifications of nonphotic cues in two, arousal-independent and arousal-dependent, families of factors. Arousal-independent factors, such as melatonin (always secreted during nighttime, independently of daily activity pattern) or γ-aminobutyric acid (GABA), have shifting effects at the same circadian times in both nocturnal and diurnal rodents. By contrast, arousal-dependent factors, such as serotonin (its cerebral levels follow activity pattern), induce phase shifts only during resting and have opposite modulating effects on photic resetting between diurnal and nocturnal species. Contrary to light and arousal-independent nonphotic cues, arousal-dependent nonphotic stimuli provide synchronizing feedback signals to the SCN clock in circadian antiphase between nocturnal and diurnal animals.

scholarly journals Molecular circadian rhythm shift due to bright light exposure before bedtime is related to subthreshold bipolarity

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chul-Hyun Cho ◽  
Joung-Ho Moon ◽  
Ho-Kyoung Yoon ◽  
Seung-Gul Kang ◽  
Dongho Geum ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Light Exposure ◽  
Bright Light ◽  
Bright Light Exposure

scholarly journals Diurnal rhythms of urine volume and electrolyte excretion in healthy young men under differing intensities of daytime light exposure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isuzu Nakamoto ◽  
Sayaka Uiji ◽  
Rin Okata ◽  
Hisayoshi Endo ◽  
Sena Tohyama ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Light Exposure ◽  
Urine Volume ◽  
Bright Light ◽  
Random Order ◽  
Diurnal Rhythms ◽  
Light Conditions ◽  
Electrolyte Excretion ◽  
Daily Urine ◽  
Bright Light Exposure

AbstractIn humans, most renal functions, including urine volume and electrolyte excretions, have a circadian rhythm. Light is a strong circadian entrainment factor and daytime-light exposure is known to affect the circadian rhythm of rectal temperature (RT). The effects of daytime-light exposure on the diurnal rhythm of urinary excretion have yet to be clarified. The aim of this study was to clarify whether and how daytime exposure to bright-light affects urinary excretions. Twenty-one healthy men (21–27 years old) participated in a 4-day study involving daytime (08:00–18:00 h) exposure to two light conditions, Dim (< 50 lx) and Bright (~ 2500 lx), in a random order. During the experiment, RT was measured continuously. Urine samples were collected every 3 ~ 4 h. Compared to the Dim condition, under the Bright condition, the RT nadir time was 45 min earlier (p = 0.017) and sodium (Na), chloride (Cl), and uric acid (UA) excretion and urine volumes were greater (all p < 0.001), from 11:00 h to 13:00 h without a difference in total daily urine volume. The present results suggest that daytime bright light exposure can induce a phase shift advance in urine volume and urinary Na, Cl, and UA excretion rhythms.

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