The effect of circadian rhythms on shipping accidents

Journal of Navigation ◽

10.1017/s0373463321000333 ◽

2021 ◽

pp. 1-11

Author(s):

Juan Vinagre-Ríos ◽

José-Manuel Pérez-Canosa ◽

Santiago Iglesias-Baniela

Keyword(s):

Circadian Rhythms ◽

Biological Feature ◽

Night Time ◽

Dim Light ◽

Night Shifts

Abstract It is a well-known fact that humans are subject to circadian alterations caused by the action of sunlight. This strongly affects their behaviour and skill, making them change their level of alertness from high at daytime to low at night-time. Taking into account this biological feature, and considering that commercial shipping is one of the oldest round-the-clock activities, raises the question whether bridge watchkeepers can carry out their tasks on night shifts with the same level of alertness as on day shifts. Furthermore, night bridge watchkeeping has to be performed in darkness or very dim light to improve the visual capacity of lookouts. A sample of vessel collisions was analysed and it was find out that this kind of accident tends to be more frequent and more serious during the darkness period of the solar day.

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Intermittent bright light and exercise to entrain human circadian rhythms to night work

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1999.277.6.r1598 ◽

1999 ◽

Vol 277 (6) ◽

pp. R1598-R1604 ◽

Cited By ~ 28

Author(s):

Erin K. Baehr ◽

Louis F. Fogg ◽

Charmane I. Eastman

Keyword(s):

Circadian Rhythms ◽

Intermittent Exercise ◽

Bright Light ◽

Phase Shifts ◽

Night Work ◽

Temperature Minimum ◽

Daytime Sleep ◽

Human Circadian Rhythms ◽

Dim Light ◽

Night Shifts

Bright light can phase shift human circadian rhythms, and recent studies have suggested that exercise can also produce phase shifts in humans. However, few studies have examined the phase-shifting effects of intermittent bright light, exercise, or the combination. This simulated night work field study included eight consecutive night shifts followed by daytime sleep/dark periods (delayed 9 h from baseline). There were 33 subjects in a 2 × 2 design that compared 1) intermittent bright light (6 pulses, 40-min long each, at 5,000 lx) versus dim light and 2) intermittent exercise (6 bouts, 15-min long each, at 50–60% of maximum heart rate) versus no exercise. Bright light and exercise occurred during the first 6 h of the first three night shifts. The circadian phase marker was the demasked rectal temperature minimum. Intermittent bright-light groups had significantly larger phase delays than dim-light groups, and 94% of subjects who received bright light had phase shifts large enough for the temperature minimum to reach daytime sleep. Exercise did not affect phase shifts; neither facilitating nor inhibiting phase shifts produced by bright light.

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Impacts of home lighting on human health

Lighting Research and Technology ◽

10.1177/14771535211021064 ◽

2021 ◽

Vol 53 (5) ◽

pp. 453-475

Author(s):

C Ticleanu

Keyword(s):

Energy Efficiency ◽

Circadian Rhythms ◽

Human Health ◽

Electromagnetic Fields ◽

Good Health ◽

Sleep Patterns ◽

Light At Night ◽

Night Time ◽

Potential Health ◽

Areas Of Concern

Typical home lighting practice is mainly centred on visual aspects to enable safe movement between spaces, flexibility in multiuse spaces, a sense of aesthetics and energy efficiency. Whilst lighting impacts on the health of residents have not received similar consideration, this area is gaining increasing interest. This is even more important and actual in the context of the recent pandemic where people have been working or studying from home. A combination of bright daytime light and night-time darkness is essential for circadian entrainment and maintenance of a regular daily sleep–wake cycle, whereas exposure to light at night can negatively impact circadian rhythms and sleep patterns and ultimately lead to potential health problems. Additionally, lighting also has the potential to affect health through associated effects such as flicker, glare, optical hazards or electromagnetic fields. This article discusses the main areas of concern related to home lighting and outlines general recommendations to limit detrimental effects and contribute to good health.

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Are doctors working the EWTD night shift pattern less tired?

Bulletin of The Royal College of Surgeons of England ◽

10.1308/147363507x177063 ◽

2007 ◽

Vol 89 (3) ◽

pp. 98-100 ◽

Cited By ~ 2

Author(s):

B Levy ◽

C Dowson ◽

J Clark

Keyword(s):

Night Shift ◽

European Working Time Directive ◽

Night Time ◽

Hours Worked ◽

Rest Periods ◽

European Working ◽

Call System ◽

Shift Pattern ◽

Working Time Directive ◽

Night Shifts

The introduction of the European Working Time Directive (EWTD) has resulted in shift pattern rotas that include a week of night shifts. The EWTD was introduced to reduce the number of hours worked per week and consequently ensure that tired doctors were not treating patients. A week of night shifts allows rotas to meet the EWTD requirements while providing night-time cover with regular interspersed rest periods, which seems an advantage over the now largely redundant on-call system.

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Transient anhedonia phenotype and altered circadian timing of behaviour during night-time dim light exposure in Per3−/− mice, but not wildtype mice

Scientific Reports ◽

10.1038/srep40399 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 9

Author(s):

Bruno Jacson Martynhak ◽

Alexandra L. Hogben ◽

Panos Zanos ◽

Polymnia Georgiou ◽

Roberto Andreatini ◽

...

Keyword(s):

Light Exposure ◽

Night Time ◽

Circadian Timing ◽

Dim Light

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Melatonin phase shifts human circadian rhythms in a placebo-controlled simulated night-work study

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00135.2001 ◽

2002 ◽

Vol 282 (2) ◽

pp. R454-R463 ◽

Cited By ~ 63

Author(s):

Katherine M. Sharkey ◽

Charmane I. Eastman

Keyword(s):

Circadian Rhythms ◽

Shift Work ◽

Phase Shifts ◽

Night Work ◽

Phase Shifting ◽

Jet Lag ◽

Work Study ◽

Temperature Minimum ◽

Sleep Schedule ◽

Dim Light

There has been scant evidence for a phase-shifting effect of melatonin in shift-work or jet-lag protocols. This study tested whether melatonin can facilitate phase shifts in a simulated night-work protocol. Subjects ( n = 32) slept in the afternoons/evenings before night work (a 7-h advance of the sleep schedule). They took melatonin (0.5 mg or 3.0 mg) or placebo before the first four of eight afternoon/evening sleep episodes at a time when melatonin has been shown to phase advance the circadian clock. Melatonin produced larger phase advances than placebo in the circadian rhythms of melatonin and temperature. Average phase advances (±SD) of the dim light melatonin onset were 1.7 ± 1.2 h (placebo), 3.0 ± 1.1 h (0.5 mg), and 3.9 ± 0.5 h (3.0 mg). A measure of circadian adaptation, shifting the temperature minimum enough to occur within afternoon/evening sleep, showed that only subjects given melatonin achieved this goal (73% with 3.0 mg, 56% with 0.5 mg, and 0% with placebo). Melatonin could be used to promote adaptation to night work and jet travel.

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Evaluation of Cardiac Circadian Rhythm Deconditioning Induced by 5-to-60 Days of Head-Down Bed Rest

Frontiers in Physiology ◽

10.3389/fphys.2020.612188 ◽

2021 ◽

Vol 11 ◽

Author(s):

Sarah Solbiati ◽

Alba Martin-Yebra ◽

Pierre Vaïda ◽

Enrico G. Caiani

Keyword(s):

Circadian Rhythms ◽

Recovery Period ◽

Oscillation Amplitude ◽

Bed Rest ◽

Heart Beat ◽

Night Time ◽

Mission Success ◽

The Difference ◽

Orthostatic Position ◽

The Impact

Head-down tilt (HDT) bed rest elicits changes in cardiac circadian rhythms, generating possible adverse health outcomes such as increased arrhythmic risk. Our aim was to study the impact of HDT duration on the circadian rhythms of heart beat (RR) and ventricular repolarization (QTend) duration intervals from 24-h Holter ECG recordings acquired in 63 subjects during six different HDT bed rest campaigns of different duration (two 5-day, two 21-day, and two 60-day). Circadian rhythms of RR and QTend intervals series were evaluated by Cosinor analysis, resulting in a value of midline (MESOR), oscillation amplitude (OA) and acrophase (φ). In addition, the QTc (with Bazett correction) was computed, and day-time, night-time, maximum and minimum RR, QTend and QTc intervals were calculated. Statistical analysis was conducted, comparing: (1) the effects at 5 (HDT5), 21 (HDT21) and 58 (HDT58) days of HDT with baseline (PRE); (2) trends in recovery period at post-HDT epochs (R) in 5-day, 21-day, and 60-day HDT separately vs. PRE; (3) differences at R + 0 due to bed rest duration; (4) changes between the last HDT acquisition and the respective R + 0 in 5-day, 21-day, and 60-day HDT. During HDT, major changes were observed at HDT5, with increased RR and QTend intervals’ MESOR, mostly related to day-time lengthening and increased minima, while the QTc shortened. Afterward, a progressive trend toward baseline values was observed with HDT progression. Additionally, the φ anticipated, and the OA was reduced during HDT, decreasing system’s ability to react to incoming stimuli. Consequently, the restoration of the orthostatic position elicited the shortening of RR and QTend intervals together with QTc prolongation, notwithstanding the period spent in HDT. However, the magnitude of post-HDT changes, as well as the difference between the last HDT day and R + 0, showed a trend to increase with increasing HDT duration, and 5/7 days were not sufficient for recovering after 60-day HDT. Additionally, the φ postponed and the OA significantly increased at R + 0 compared to PRE after 5-day and 60-day HDT, possibly increasing the arrhythmic risk. These results provide evidence that continuous monitoring of astronauts’ circadian rhythms, and further investigations on possible measures for counteracting the observed modifications, will be key for future missions including long periods of weightlessness and gravity transitions, for preserving astronauts’ health and mission success.

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Changes in Plasma Tryptophan and Melatonin Content in Penned Sheep

Australian Journal of Biological Sciences ◽

10.1071/bi9780049 ◽

1978 ◽

Vol 31 (1) ◽

pp. 49

Author(s):

DJ Kennaway ◽

KJ Porter ◽

RF Seamark

Keyword(s):

Circadian Rhythms ◽

Plasma Levels ◽

Blood Sampling ◽

Night Time ◽

Sampling Device ◽

Blood Constituents ◽

Circadian Changes ◽

Plasma Tryptophan ◽

Tryptophan Content ◽

The Relationship

The present study was undertaken to examine the relationship between the plasma levels of melatonin and its precursor tryptophan. No circadian changes in plasma total tryptophan content were evident which could be related to the marked night-time rise in plasma melatonin. An automated programmable blood sampling device suited to studies of circadian rhythms in blood constituents is described.

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Characterizing the modern light environment and its influence on circadian rhythms

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0721 ◽

2021 ◽

Vol 288 (1955) ◽

pp. 20210721

Author(s):

Dennis Khodasevich ◽

Susan Tsui ◽

Darwin Keung ◽

Debra J. Skene ◽

Victoria Revell ◽

...

Keyword(s):

Circadian Rhythms ◽

Light Exposure ◽

Circadian Disruption ◽

Light Sources ◽

Night Time ◽

Circadian Phase ◽

Temperature Rhythm ◽

Four Seasons ◽

Significant Difference ◽

The Impact

Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. Our results demonstrate that humans are minimizing natural seasonal differences in light exposure, and that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized.

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