ArticleInternational journal of environmental research and public health2020
Comparison of Cortisol level by Shift Cycle in Korean Firefighters.
Article in International journal of environmental research and public health, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers.
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Who cites it
15 citing papers in PubMed, 17 citations in OpenAlex.
- Glucose as a Biomarker for Stress in Firefighters.Journal of occupational and environmental medicine · 2026Article
- The sleep quality and influencing factors among midwives in China: a cross-sectional study.Frontiers in public health · 2025Article
- Cortisol Reactivity to Acute Psychosocial Stress in Physician Burnout.Biomedicines · 2024Article
- Latent transition analysis on post-traumatic stress and post-traumatic growth among firefighters.European journal of psychotraumatology · 2024Article
- A Study of Diurnal Cortisol Adaptations in Sleep-Deprived Firefighters During a 72-Hour Work Shift: A Case Series.Cureus · 2023Article
- Review
- Latent profile analysis of post-traumatic stress and post-traumatic growth among firefighters.European journal of psychotraumatology · 2023Article
- Working hours, sleep, and fatigue in the public safety sector: A scoping review of the research.American journal of industrial medicine · 2022Article
- Investigating the influence of shift work rosters on stress measured as cortisol in hair during the SARS-CoV-2 pandemic.Psychoneuroendocrinology · 2022Article
- Association between sleep quality and type of shift work in Korean firefighters.Annals of occupational and environmental medicine · 2022Article
- The Validity of Virtual Courage for Trainees in High-Risk Occupations.Psychology research and behavior management · 2022Article
- Hair Cortisol Concentration as a Biomarker of Sleep Quality and Related Disorders.Life (Basel, Switzerland) · 2021Review
- Personality Traits and Insomnia Symptoms in Shift Workers.Frontiers in psychology · 2021Article
- The Development of a Sleep Intervention for Firefighters: The FIT-IN (Firefighter's Therapy for Insomnia and Nightmares) Study.International journal of environmental research and public health · 2020Article
- Relationships among shift work, hair cortisol concentration and sleep disorders: a cross-sectional study in China.BMJ open · 2020Article
Corrections and comments
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Authors and funding
5 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
(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.
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