Physiology of Circadian Entrainment

Physiological Reviews, Journal Year: 2010, Volume and Issue: 90(3), P. 1063 - 1102

Published: July 1, 2010

Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since period of this oscillation is ∼24 h, to keep synchrony with environment, need be entrained daily means Zeitgeber (“time giver”) signals, such as light-dark cycle. Recent advances neurophysiology and molecular biology rhythmicity allow better understanding synchronization. In review we cover several aspects mechanisms for photic entrainment mammalian rhythms, retinal sensitivity light novel photopigments well variations retina that contribute regulation physiology. Downstream from retina, examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction SCN receptors resulting signal transduction pathways neurons, putative neuron-glia interactions. Finally, describe analyze gene expression its importance mechanisms, disorders or diseases related deficits, experimental clinical treatments.

Language: Английский

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Sex difference in the near-24-hour intrinsic period of the human circadian timing system

Proceedings of the National Academy of Sciences, Journal Year: 2011, Volume and Issue: 108(supplement_3), P. 15602 - 15608

Published: May 2, 2011

The circadian rhythms of melatonin and body temperature are set to an earlier hour in women than men, even when the men maintain nearly identical consistent bedtimes wake times. Moreover, tend up exhibit a greater preference for morning activities men. Although neurobiological mechanism underlying this sex difference alignment is unknown, multiple studies nonhuman animals have demonstrated period that could account such between Whether intrinsic humans underlies unknown. We analyzed precise estimates collected from 157 individuals (52 women, 105 men; aged 18–74 y) studied month-long inpatient protocol designed minimize confounding influences on estimation. Overall, average population was very close 24 h [24.15 ± 0.2 (24 9 min 12 min)]. further found significantly shorter [24.09 5 min)] [24.19 11 min); P < 0.01] proportion periods 24.0 (35% vs. 14%; 0.01). observed may implications understanding differences habitual sleep duration insomnia prevalence.

Language: Английский

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Effect of Light on Human Circadian Physiology

Sleep Medicine Clinics, Journal Year: 2009, Volume and Issue: 4(2), P. 165 - 177

Published: June 1, 2009

Language: Английский

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Shift work and the assessment and management of shift work disorder (SWD)

Sleep Medicine Reviews, Journal Year: 2012, Volume and Issue: 17(1), P. 41 - 54

Published: May 3, 2012

Language: Английский

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Fatigue Risk Management in the Workplace

Journal of Occupational and Environmental Medicine, Journal Year: 2012, Volume and Issue: 54(2), P. 231 - 258

Published: Jan. 21, 2012

PURPOSE AND INTRODUCTION Key Points: Fatigue is an unsafe condition in the workplace. Like other risk factors, fatigue can be managed. Safety and productivity workplace are intimately related to worker health. A may have chemical, physical, biological, and/or psychosocial hazards that potential impact physical psychological well-being. How these managed key. which well-controlled, with active culture of health a supportive work environment, enhance well-being, both on off job. Healthier employees result fewer claims, better safety records, greater productivity. Well-rested, alert critical safe productive operations. Virtually everyone experiences some level from time time. However, excessive while working important interrelationship health, safety, create vicious or virtuous cycle. Specific medical lifestyle interventions been shown promote well-rested workforce. In addition, specific factors organization either alertness fatigue. Because productivity, any individuals extended hours during people typically sleep benefit addressing This particularly for safety-sensitive operations such as transportation, care, energy industries. Occupational environmental medicine (OEM) physicians, whether directly employed by serving consultant organization, role play management. Where no program currently place, OEM physicians should advise management opportunities through development system (FRMS). FRMS place under development, its implementation, sustainability. The purpose this article provide information assist roles. It designed background, key concepts, references needed support FRMS. not intended complete “how to” guide area. Design implementation comprehensive requires wide range skills, backgrounds, resources. Many resources available within organization; however, it likely will in-house need contracted out. ownership must reside senior ensure sustained effort. Ergo, physician inspire participate successful program. THE RISK OF EMPLOYEE FATIGUE IN 24/7 WORKPLACE duration timing (circadian rhythm) sleep. Inadequate correlated variety adverse outcomes. Various shift schedules affect injury rate. Difference Between Sleepiness When term used, many think same sleepiness, but actually two different (although related) states. tendency fall asleep; body's response loss prolonged mental exertion. reduced sedentary activity rest without sleeping, whereas subjective sleepiness propensity often exacerbated rest.1 Sleep accompanied decreased then leads attention detail, impaired judgment, slowed overall Table 1 lists several lead increased resultant degree impairment.TABLE 1: Risk FactorsFatigue resulting insufficient poor quality safety-related consequences, including reaction time, vigilance, decision-making ability, distraction complex tasks, awareness situations. deprivation has long recognized unmet public challenge.2–4 believe they adapt chronic recovery only single episode, studies case. Science Sleep, Circadian Rhythms, Two contributors disruptions normal Most go cyclic stages, each cycle about 90 minutes length, period. Disruption shortening even eliminating stages attendant consequences. identified evaluated use electroencephalography. There five basic 4 comprising non-rapid eye movement sleep, stage 5 rapid (characterized movements). require between 7 8 per night fully alert, although 6 hours, others 10 night. considering what seems when individual's intrinsic circadian rhythm occurs. Humans operate daily (a generated suprachiasmatic nucleus5 generally slightly longer than 24 vary individual individual. drive (the urge sleep) increases late at reaches peak early morning hours. also small increase midafternoon. Figure depicts showing tends nadir.6 signals control rhythms alertness, core body temperature secretion hormones. These persist absence cues; affected cues light dark occur (eg, day reinforces one's rhythm). Some who required function able adjust degree; develop disorder.7FIGURE sleepiness. Used courtesy International Petroleum Industry Environmental Conservation Association/International Association Oil Gas Producers.6Types Shift Work encompass aspects scheduling. include outside would considered “normal” daytime AM PM,8 overtime (beyond 40-hour workweek), shifts (longer hours). Hours fixed rotating, modifications being predictable unpredictable. Extended voluntary mandatory. Although industries governed federal service regulations aviation, highway, rail US Department Transportation), guided industry standards resident duty Accreditation Council Graduate Medical Education), there hour issued Health Administration (OSHA). According recent survey, 20% wage salary workers regular shift, almost 15 million Americans full-time evening, night, rotating shifts, employer-arranged irregular schedules.9 do so because nature position available, choose types personal reasons (second jobs, childcare, education, pay, etc). National Foundation's 2010 America poll found one-fourth those surveyed indicated their schedule did permit them obtain adequate one-third reported sufficient best.10 Exposure ample evidence associated negative performance. is, part, due shorter obtain, misalignment. Duration less ideal among worse shifts.11 Twenty-four impair neurobehavioral performance comparable 0.10% blood alcohol level.12 Small amounts ability sustain vigilance tasks. Only 2 optimal over week decrements equal consecutive wakefulness.13 Several demonstrated incidents more task, fatigue-related coinciding period Similar impairing conditions hypoglycemia effects medications, assessing own levels reports correlating objective measures. Not works equally loss. fact, significant differences observed. One where effect transportation.14–16 Highway Traffic estimates least 100,000 police-reported crashes annually driver fatigue; cause approximately 1550 deaths, 71,000 injuries, $12.5 billion monetary losses. Transportation Board (NTSB) investigated numerous all transportation modes causal contributory factor.17 NTSB Wanted List every year since was initiated 1989. addition industry, good amount research into care workers. nurses 12.5-hour job, suffering occupational injury, making error.18 Errors injuries training sharps motor vehicle crash way home, serious error significantly exceed hours—compared 16 hours—there twice attentional failures 36% errors.18 An residents shifts.19 Using Interview Survey, Lombardi et al20 leading across multiple (Table 2). Even after controlling occupation, type sex, age, mass, work-related remained, decreasing number hours.20TABLE 2: Estimated Annualized Injury Rates/Hours Sleep*Others hours.21,22 worked prior incident occurred risk. manufacturing workers, Vegso al23 88% excess 64 before compared 40 (after within-subject variables). Research increasingly demonstrates positive association short conditions24 diabetes,25 hypertension,26 cardiovascular disease,27,28 reproductive outcomes,29 obesity issues.30,31 report Agency Cancer linked disruption cancer.32 Estimates vary, 1997, losses employers were approach $18 year.33 study $1967 employee lost loss.34 coexists causes condition-specific threefold.35 occurs successive length emerging effect.36 HISTORY LIMITATIONS DUTY-REST REGULATIONS “Hours-of-service” guidelines attempt address Other (besides spent sleeping work) alertness. Management Systems factors. Work-related new. existed man first placed environment demand food shelter exceeded easily supply. invention electric light, illumination provided fires, candles, gas lamps. sources intensity factory work, large-scale activities, fine craftwork. advent daylight. Once installed, limited Instead having summer, daylight peak, could now expected round. Factories shops run day. 1910, widespread average person slept 9 Today, 7.5 night.37 military maneuvers institution artificial light. past, most engagements ended faded, noted major battles American Civil War. vision technology expanded offensive 24-hour activity. More recently, electronic measures recall expectation respond requests zones, essentially eliminates “regular” places mode. As changes, live society, matter choice necessity modern life. Police, firefighters, hospitals, power plants, vital services cannot close down PM. Similarly, continuous refineries chemical plants take start up shut down. Thus, alternative facilities. To mitigate consequences this, laws passed limit set minimum off. common economically developed countries United States, applied States. For example: Medical: Education issues residents.38 transport: Federal Motor Carrier defining maximum drivers passenger vehicles trucks.39 Rail Improvement Act 2008 defines days well periods sets.40 increasing realization hours-of-service alone achieve maximizing (and thus fitness duty) performing work. Employee depends how including: one does work; (relative rhythm); promotes mechanisms detect obtains uses purposes; high-quality restorative sleep; emotional, interfere employer, not. enlist entire workforce partners managing Increasingly, regulators moving away pure toward FRMSs minimize fatigue, identify itself EMERGENCE AS INTERNATIONAL STANDARD FOR MITIGATING SHIFT WORK OPERATIONS analogous (or subset of) (SMS). science based, data driven, subject improvement; short, manage systems improve outcomes flexible duty-rest regulations. All stakeholders share responsibility complying improving What FRMS? Historically, largely reactive process. Incidents “learnings” communicated together appropriate controls prevent recurrence. years, moved technical business allow cost effectively balanced.41 establishment SMS acknowledges decisions made parts operational safety.42,43 acceptable therefore, techniques. principal components management, familiar practitioners. process, identifies exposed, assesses risks hazards, determines ways eliminate hazard elements policy, reporting processes, investigation, audit; traditional incorporated SMS, element formal structure involving aimed achieving safety.44 natural extend area became risk, defined “explicit processes measuring, mitigating, managing” actual company exposed.45 effective integrated supported thereby forming FRMS.46 follows: scientifically data-driven prescriptive limitations manages manner exposure operation.47,48 Features authors outlined characteristics FRMS, following concepts Moore-Ede49 essential success implementations: based: established peer-reviewed science. Data driven: based collection analysis data. Cooperative: stakeholders. Fully implemented: system-wide tools, systems, policies, procedures. Integrated: built corporate systems. Continuously improved: progressively reduces using feedback, evaluation, modification. Budgeted: justified accurate return-on-investment Owned: accepted leadership. translated still discussion, six essential45,48,50,51: policy Reporting Incident investigation Training education Internal external auditing44,52,53 include: policy; collecting hazard, analyzing instigating risk; employees; investigation; employees, families); disorder management; process internal auditing delivers corrective actions improvement sixth direct analogues SMS. unique manager ultimately accountable actively engaged. organizational trust another openly risks, “one-size-fits-all” solution needs regulatory applies. New Regulations Aviation, Railroads, Modes road transport aviation authorities Australia Zealand trial initiatives proposal stage, begun move (HoW) Indeed, heavy Transport Commission introduced September example outcome-based legislation. fundamental change Rather rules, companies focus outcome, words, new differ approaches, operators employees' consistent chain established. Legislation solely operating company. parties supply legal preventing influencing Responsible prime contractor, scheduler, consignor, consignee, loading manager.54 Organizations follow standard HoW or, if demonstrate sophisticated manner, according HoW.55 adopted safety56 providing detailed recommendations Importantly, features patterns relationship acts operator recognizing safety. Elsewhere, principle establishing received Europe. At 2009, European Aviation Authority released Notice Proposed Amendment requiring commercial air mid-2012.57 Amendment, basis applying derogation existing flight limitations. derogation, present case, successfully demonstrating equivalent maintained limits. factor accidents. Over caused obstructive apnea (OSA). 2008, formalized recommended guidance establish design methodology effectiveness systems.58 Airline Extension airlines plan October 31, 2010. Spread Through Activities concept relatively industries, examples countermeasures programs, programs activities. Mining Tasmanian Minerals published Guide 2004,59 South Wales Mines Advisory group mining 2009.60 Starting 1990s, Australian Association's Safe Working Project ratified 2002.61 approach, assessment, complex.62 Their code practice outlines assessment series strategies comprise principles schedules. Pipeline Hazardous Materials recently Rulemaking room human factors.63 document includes section mitigation Standards Institute Standard Petrochemical Refining Industries Chemical Hazard Investigation Board's explosion BP's Texas City refinery 2005,64 (API) Steelworkers Union consensus (ANSI) standard. prevention refining petrochemical that, minimum, withdrew discussions, accordance terms API standardization procedures,65 ANSI/API Recommended Practice RP755 Personnel Industries66 April employs systematic combination critical. specifically facilities OSHA's Process Standard, 29 CFR 1910.119.67 Companies voluntarily advantage implement operations, upstream international Integration With part focused Within driven commensurate operation. considers provides integrated, defenses against effective, clear lines accountability, just culture, integration company's everyday business. BUILDING SUPPORT AN responsible Given emp

Language: Английский

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The Impact of Shift Work on Sleep, Alertness and Performance in Healthcare Workers

Scientific Reports, Journal Year: 2019, Volume and Issue: 9(1)

Published: March 15, 2019

Abstract Shift work is associated with impaired alertness and performance due to sleep loss circadian misalignment. This study examined between shift types (day, evening, night), during day night shifts in 52 intensive care workers. Sleep wake duration were evaluated using wrist actigraphs diaries. Subjective sleepiness (Karolinska Sleepiness Scale, KSS) Psychomotor Vigilance Test (PVT) shift, on the first subsequent (3 rd , 4 th or 5 ). Circadian phase was assessed urinary 6-sulphatoxymelatonin rhythms. most restricted consecutive (5.74 ± 1.30 h), (5.83 0.92 h) evening (5.20 0.90 h). KSS PVT mean reaction times higher at end of compared highest night. On nights, working acrophase melatonin rhythm led poorer outcomes PVT. In rotating workers, early can be similar restriction shifts, particularly when scheduled immediately following an shift. Alertness remain given lack adaptation work. Although healthcare workers perceive themselves less alert objective equally nights.

Language: Английский

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The human circadian system adapts to prior photic history

The Journal of Physiology, Journal Year: 2011, Volume and Issue: 589(5), P. 1095 - 1102

Published: Jan. 11, 2011

Light is the most potent stimulus for synchronizing endogenous circadian timing system to 24 h day. The timing, intensity, duration, pattern and wavelength of light are known modulate photic resetting acute suppression melatonin secretion. effect prior history on these processes, however, not well understood. Although previous studies have shown that affects in response a subsequent exposure, here we show first time very dim history, as opposed typical indoor room illuminance, amplifies phase-shifting sub-saturating by 60–70%. This greater efficacy provides evidence dynamic adaptive changes sensitivity ocular photoreception. plasticity has important implications optimization therapy treatment rhythm sleep disorders.

Language: Английский

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The inner clock—Blue light sets the human rhythm

Journal of Biophotonics, Journal Year: 2019, Volume and Issue: 12(12)

Published: Aug. 21, 2019

Visible light synchronizes the human biological clock in suprachiasmatic nuclei of hypothalamus to solar 24-hour cycle. Short wavelengths, perceived as blue color, are strongest synchronizing agent for circadian system that keeps most and psychological rhythms internally synchronized. Circadian rhythm is important optimum function organisms sleep-wake disruptions or chronic misalignment often may lead psychiatric neurodegenerative illness. The beneficial effect on synchronization, sleep quality, mood, cognitive performance depends not only spectral composition but also timing exposure its intensity. Exposure during day suppress melatonin secretion, hormone produced by pineal gland plays crucial role entrainment. While keeping organism's wellbeing, alertness, day, low-intensity directly before bedtime, have serious implications phase cycle durations. This rises inevitably need solutions improve today's modern society where emitting devices ever increasing.

Language: Английский

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High risk of near-crash driving events following night-shift work

Proceedings of the National Academy of Sciences, Journal Year: 2015, Volume and Issue: 113(1), P. 176 - 181

Published: Dec. 22, 2015

Significance Drowsy driving is a major public health issue, particularly impacting the 9.5 million shift workers in America. Previous reports have assessed impact of night work on simulators. This real-vehicle study demonstrated increased objective and subjective drowsiness degraded daytime performance 16 night-shift while after work, deteriorating with drive duration. No near-crashes occurred during sleep; 11 night-work; all at least 45 min driving. Policy makers night-workers should consider avoiding/minimizing or deploying effective countermeasures when to reduce drowsy preventable crashes injuries this high-risk population.

Language: Английский

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Genetic Basis of Chronotype in Humans: Insights From Three Landmark GWAS

SLEEP, Journal Year: 2016, Volume and Issue: 40(2)

Published: Dec. 9, 2016

Chronotype, or diurnal preference, refers to behavioral manifestations of the endogenous circadian system that governs preferred timing sleep and wake. As variations in perturbations are linked disease development, fundamental biology chronotype has received attention for its role regulation dysregulation related illnesses. Family studies indicate is a heritable trait, thus directing toward genetic basis. Although discoveries from molecular candidate genes have shed light onto architecture, contribution variation remained unclear with few variants identified. In advent large-scale genome-wide association (GWAS), scientists now ability discover novel common associated complex phenotypes. Three recent GWASs were conducted on subjects European ancestry 23andMe cohort UK Biobank. This review discusses findings these landmark context prior research.We systematically reviewed compared methodological analytical approaches results across three chronotype.A good deal consistency was observed 9 identified 2 3 GWASs. Several previously unknown influence identified.GWAS an important tool identifying phenotype, which can supplement guide science. Future directions model systems discovery rare discussed.

Language: Английский

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