Comparison of Cortisol level by Shift Cycle in Korean Firefighters.
circadian rhythm
cortisol
firefighter
shift cycle
shift work
Journal
International journal of environmental research and public health
ISSN: 1660-4601
Titre abrégé: Int J Environ Res Public Health
Pays: Switzerland
ID NLM: 101238455
Informations de publication
Date de publication:
02 07 2020
02 07 2020
Historique:
received:
18
05
2020
revised:
29
06
2020
accepted:
30
06
2020
entrez:
8
7
2020
pubmed:
8
7
2020
medline:
21
11
2020
Statut:
epublish
Résumé
(1) Study Objectives: By investigating the change of cortisol levels during shift cycles among professional firefighters in Korea, this study aims to evaluate the difference between individuals' stress response and the recovery of their circadian rhythm after working night shifts. (2) Methods: A total of 325 shift firefighters, who were working in 3, 6, 9, or 21 day cycles, participated in the study. Their urinary and serum cortisol levels were measured during the day (09-18), during the night (18-09), and every 24 h (09-09) per shift cycle, and adjustments were made for confounding factors. (3) Results: Serum cortisol levels were significantly increased after working during the night or for 24 h compared with that of working throughout the day. However, whether working night or 24 h shifts, the serum cortisol levels were undoubtedly different based on the 3, 6, 9, or 21 day cycles. In all shift cycles, the urinary cortisol level decreased during the night or throughout the 24 h shifts compared with sleeping during this time, but this was considered to be significantly applicable only to those working in 21 day cycles. Additionally, in serial measurements, the recovery of urinary cortisol secretion after a night or 24 h shift was successful for individuals working in 9 day cycles, but the recovery was delayed for those working in 6 or 21 day cycles. (4) Conclusions: After analyzing the urine cortisol levels, the study indicates that only subjects working in 9 day cycles fully recovered their circadian rhythm while those working in 6 day or 21 day cycles did not completely recover. Therefore, it is important to recognize how stressful night shifts can be, and it is crucial to enhance firefighters' current shift cycles in order to allow sufficient recovery of their circadian rhythm as well as the prevention of disrupting their circadian rhythm after working at night. Further research is necessary to take into account the amount of work load, the challenges of being sleep deprived, and the individual's capacity to overcome sleepiness.
Identifiants
pubmed: 32630691
pii: ijerph17134760
doi: 10.3390/ijerph17134760
pmc: PMC7370292
pii:
doi:
Substances chimiques
Hydrocortisone
WI4X0X7BPJ
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
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