Comparison of Melatonin Profile and Alertness of Firefighters with Different Work Schedules

Abstract

Introduction:A two-shift work schedule with different rotations is common among firefighters in Iranian petrochemical companies. This study compared salivary melatonin and sleepiness on the last night before turning to day shift at 19:00, 23:00, 3:00, and 7:00 among petrochemical firefighters (PFFs) working seven and four consecutive night shifts.Methods:Sixty four PFFs working in the petrochemical industry were selected. To measure melatonin, saliva samples were taken, whereas the KSS index was used to assess sleepiness. Chi-square and independent samples t-test were carried out to analyze the data, and generalized linear model (GLM) was employed to determine the effect of confounding factors such as lighting and caffeine.Results:The levels of melatonin at 3:00 and 7:00, and the overall changes during the shift in the two shift patterns under the study were different (P < 0.05). Sleepiness was significantly different only at 3:00 in the two studied shift patterns, while the effects of lighting and caffeine on melatonin changes were not significant (P > 0.05).Conclusion:It seems that a slow shift rotation is better because it reduces the secretion of melatonin (hence reducing sleepiness during the night) and changes the peak of melatonin secretion to the daytime, which is a sign of adaptation.

Comparing task performance, visual comfort and alertness under different lighting sources: an experimental study

“…This scale, which has already been validated against EEG data by Åkerstedt and Gillberg (1990[ 1 ]), is a subjective rating in which each person indicates their current alertness level on a 9-point likert scale ranging from (1) “extremely alert” to (9) “fighting sleep”. Various studies have utilized KSS to examine drowsiness and consciousness in different workplaces (Kazemi et al, 2016[ 16 ], 2018[ 17 ][ 18 ]).…”

Shifted Firefighter Health Investigation by Personal Health Insurance Record in Taiwan

“… 6 Table 1 lists recent studies on occupational injuries that are related to firefighters and shift rotations. These mainly involve sleeping, 14 , 15 depression and stress, 16 , 17 cognitive functions, 18 cancer, 19 , 20 hypertension, 21 physical activity and obesity, 22–24 metabolic syndromes, 25 and injuries and musculoskeletal disorders. 26 , 27 According to the 2154 work injuries that were recorded from 2010 to 2015 in South Korea in reference, 28 the majority of injuries concerned the upper and lower back (25.3%).…”

“… Year Country Subjects Stuy Method Major Finding 16 2008 japan 1301 shift‐work firefighters. CES‐D; job dissatisfaction survey Workload, intergroup conflict, social support from a supervisor related to depressive symptoms and/or job dissatisfaction 14 2018 Iranian 60 shift work firefighters melatonin, sleepness Melatonin level change at 3:00 and 7:00 15 2017 Korea 110 shift work firefighters Pittsburgh Sleep Quality Index, the Insomnia Severity Index, the Epworth Sleepiness Score, the Stanford Sleepiness Score, the Fatigue Severity Scale, and the Berlin Questionnaire 60% of the participating firefighters had a certain degree of insomnia 17 2017 Finland firefighters Heart rate variability during shifts. Physiological load and psychological stress were temporarily high 18 2020 Poland 18 paramedics, 16 firefighters and 17 day worker EEG Higher amplitude of the P200 and P300 potential 19 2018 Danish 11,775 firefighters mortality ratios Death from stomach cancer increased 21 2016 USA 330 firefighters Blood pressure Sixteen 24-h shifts had 5.0 mmHg higher DBP 22 2016 …”

Physiological strain and decision making affected by different cooling tactics following live‐fire training

“…Fire service workers perform physical activities in extreme conditions of high temperature, smoke, and sleep deprivation (e.g., night shift work), increasing their risk of heat injury. Heat injury is associated with impaired physical and mental performance (Golbabaei et al, ; Kazemi et al, ; Kazemi, Zare, & Hemmatjo, ; Zare, Hasheminejad, Bateni, et al, ; Zare, Hasheminejad, Shirvan, et al, ).…”