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Disturbance of the Circadian System in Shift Work and Its Health Impact

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journal contribution
posted on 2023-11-23, 01:58 authored by DB Boivin, P Boudreau, Anastasi KosmadopoulosAnastasi Kosmadopoulos
The various non-standard schedules required of shift workers force abrupt changes in the timing of sleep and light-dark exposure. These changes result in disturbances of the endogenous circadian system and its misalignment with the environment. Simulated night-shift experiments and field-based studies with shift workers both indicate that the circadian system is resistant to adaptation from a day- to a night-oriented schedule, as determined by a lack of substantial phase shifts over multiple days in centrally controlled rhythms, such as those of melatonin and cortisol. There is evidence that disruption of the circadian system caused by night-shift work results not only in a misalignment between the circadian system and the external light-dark cycle, but also in a state of internal desynchronization between various levels of the circadian system. This is the case between rhythms controlled by the central circadian pacemaker and clock genes expression in tissues such as peripheral blood mononuclear cells, hair follicle cells, and oral mucosa cells. The disruptive effects of atypical work schedules extend beyond the expression profile of canonical circadian clock genes and affects other transcripts of the human genome. In general, after several days of living at night, most rhythmic transcripts in the human genome remain adjusted to a day-oriented schedule, with dampened group amplitudes. In contrast to circadian clock genes and rhythmic transcripts, metabolomics studies revealed that most metabolites shift by several hours when working nights, thus leading to their misalignment with the circadian system. Altogether, these circadian and sleep-wake disturbances emphasize the all-encompassing impact of night-shift work, and can contribute to the increased risk of various medical conditions. Here, we review the latest scientific evidence regarding the effects of atypical work schedules on the circadian system, sleep and alertness of shift-working populations, and discuss their potential clinical impacts.

Funding

Category 3 - Industry and Other Research Income

History

Volume

37

Issue

1

Start Page

3

End Page

28

Number of Pages

26

eISSN

1552-4531

ISSN

0748-7304

Publisher

SAGE Publications

Publisher License

CC BY-NC

Additional Rights

CC-BY-NC

Language

en

Peer Reviewed

  • Yes

Open Access

  • Yes

Author Research Institute

  • Appleton Institute

Era Eligible

  • Yes

Medium

Print-Electronic

Journal

Journal of Biological Rhythms