Comparison of Melatonin Profile and Alertness of Firefighters with Different Work Schedules (original) (raw)
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Health and Safety at Work, 2020
Introduction: This paper aims to explore the main effect of night shift rotation speed on the pattern of melatonin secretion and the sleepiness, among control room operators (CORs) in a petrochemical industry Material and method: In this study, 60 CORs operators within two different patterns, including 7 nights and 3 nights shift works were selected from a petrochemical industry to investigate the influence of rotation speed on their melatonin secretion and the sleepiness pattern. Thus, melatonin was sampled from saliva, and the sleepiness and sleep quality were assessed using Karolinska Sleepiness Scale (KSS) index. Data analysis was carried out using spss18, Chi square, t-test, and GLM model. Results: Melatonin values and their general changes during shift were noticeably different in two proposed patterns (P <0.05). The sleepiness index was significantly different only at 3:00 in both patterns, whereas the interaction of light and caffeine on both melatonin changes and sleepin...
Field Study of Effects of Night Shifts on Cognitive Performance, Salivary Melatonin, and Sleep
Safety and Health at Work, 2018
Background: Night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue. This study set out to measure cognitive performance, melatonin rhythms, and sleep after different consecutive night shifts (7 vs. 4) among control room operators (CORs). Methods: The participants included 60 CORs with a mean age of 30.2 years (standard deviation, 2.0) from a petrochemical complex located in Southern Iran. Cognitive performance was assessed using the n-back task and continuous performance test. To evaluate melatonin, saliva was collected and tested by enzymelinked immunosorbent assay. To assess sleep and sleepiness, the Pittsburgh Sleep Quality Index and Karolinska Sleepiness Scale were used, respectively. Results: Individuals who worked 7 consecutive night shifts had a significantly better cognitive performance and sleep quality than those who worked 4 consecutive night shifts. However, salivary melatonin profile and sleepiness trend were not affected by shift type. Conclusion: The main duty of CORs working night shifts at the studied industry included managing safety-critical processes through complex displays; a responsibility that demands good cognitive performance and alertness. It is suggested that an appropriate number of consecutive night shifts in a rotating shift system should be planned with the ultimate aim of improving CROs performance/alertness and enhancing safety.
Melatonin Rhythms in Night Shift Workers
Sleep, 1992
For some time, it has remained uncertain whether the circadian rhythms of permanent night shift workers are adapted to their night-active schedule. Previous studies of this question have often been limited by "masking" (evoked) effects of sleep and activity on body temperature and cortisol, used as marker rhythms. In this study, the problem of masking was minimized by measuring the timing of melatonin production under dim light conditions. Nine permanent night shift workers were admitted to the Clinical Research Center (CRC) directly from their last work shift of the week and remained in dim light while blood samples were obtained hourly for 24 hours. Melatonin concentrations were measured in these samples using a gas-chromatographic mass-spectrometric method. Sleep diaries were completed for two weeks prior to the: admission to the CRC. Overall, the onset of the melatonin rhythm was about 7.2 hours earlier (or 16.8 hours late:r) in the night workers compared to day-active controls. It was not possible to know whether the phase of the melatonin rhythm was the result of advances or delays. In night shift workers, sleep was initiated (on average) about three hours prior to the onset of melatonin production. In contrast, day-active subjects initiated sleep (on average) about three hours after their melatonin onset. Thus, the sleep times selected by night shift workers may not be: well-synchronized to their melatonin rhythm, assumed to mark the phase of their underlying circadian pacemaker.
Sleep Disorders in Shift Workers in the Emergency Department and Efficacy of Melatonin
No statistical data is available on the number of employees working on night shifts in Turkey. Working on shifts is associated with decreased sleep time, decreased daily sleep quality, and decreased alertness during night shifts. Increased incidences of cardiovascular disorders, peptic ulcers, and some types of cancer in shift workers are well known. Exposure to light at nighttime suppresses melatonin production. In non-synchronized circadian rhythm, disturbed melatonin secretion may lead to excessive sleep, hunger for carbohydrates, and weight gain. Melatonin is the hormone that governs sleep. It seems to be the key regulator of the sleep/wake rhythm. Exposure to light at night and disturbance of the circadian rhythm contribute to the health problems of night shift workers by disturbing melatonin production. In this review, the definitions of social jetlag, delayed sleep phase syndrome, and insomnia will be discussed. Sleep disorders in psychiatric diseases will be reviewed. Melatonergic drugs available on the market will be listed, including their contraindications and side effects. The physiopathology of sleep, sleep disorders, depression, and melatonin will be given with an extended discussion. Two recent reviews about the effect of melatonin on sleep patterns will be discussed. Finally, other treatments for sleep disorders will be summarized. In conclusion, in shift workers, sleep problems are a complex subject in which multiple pathophysiological mechanisms play roles. The double-blind randomized controlled studies, systematic reviews, and meta-analyses that have been conducted can provide only weakly positive data about the beneficial effect of melatonin use in shift workers. In the future, multi-centered and multi-participant studies will shed more light on this issue. (Eurasian J Emerg Med 2016; 15: 48-53)
A study of pattern of secretion of salivary melatonin in shift workers
Background: Globalization and industrialization lead round the clock service providers (shift workers) vulnerable for circadian rhythm sleep disorders Aim & Objective: To know how effect of shift work on secretory pattern of melatonin in saliva since there is growing evidence that antioxidant characteristic of melatonin may be reason for development of cancer in long standing shift workers in future. Materials &Method: The study was observational, controlled, parallel study carried out in 30 shift workers (mean [SD] age: 21.33 [0.48] years) and 30 age matched healthy subjects (mean [SD] age: 24.97 [2.55] years). Saliva samples for the measurement of melatonin totally were collected from participants resting in dim light at 2 hr min intervals between 20:00 and 00:00 h. Result: A decreasing time line trend of salivary secretion of melatonin was observed for shift workers. Conclusion: The circadian phase is altered in shift workers as compared to day workers using salivary melatonin concentration as a marker of the circadian phase.
Academic Emergency Medicine, 2000
Objective: To determine whether melatonin taken prior to attempted daytime sleep sessions will improve daytime sleep quality, nighttime sleepiness, and mood state in emergency medicine (EM) residents, changing from daytime to nighttime work schedules. Methods: A prospective, randomized, double-blind crossover design was used in an urban emergency department. Emergency medicine residents who worked two strings of nights, of at least three nights' duration each, and separated by at least one week of days were eligible. Subjects were randomized to receive either melatonin 1 mg or placebo, 30 to 60 minutes prior to their daytime sleep session, for three consecutive days after each night shift. Crossover to the other agent occurred during their subsequent night shifts. Objective measures of quality of daytime sleep were obtained using the Actigraph 1000. This device measures sleep motion and correlates with sleep efficiency, total sleep time, time in bed, and sleep latency. The Profile of Mood States (POMS) and the Stanford Sleepiness Scale (SSS) were also used to quantify nighttime mood and sleepiness. Results: Among the 19 volunteers studied, there was no difference in sleep efficiency (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or sleep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, respectively. In addition, neither the POMS total mood disturbance (5.769 baseline vs 12.212 melatonin vs 5.585 placebo, NS) nor the SSS (1.8846 baseline vs 2.2571 melatonin vs 2.1282 placebo, NS) demonstrated a statistical difference in nighttime mood and sleepiness between melatonin and placebo. Conclusions: There are no beneficial effects of a 1-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM residents. Key words: melatonin; mood; sleep efficiency; night shifts; emergency medicine residents. ACADEMIC EMERGENCY MEDICINE 2000; 7:955-958 The need to change from day to night shifts on a regular basis can make it difficult for emergency physicians (EPs) to maintain normal cir-
Journal of circadian rhythms, 2006
The aim of the study was to examine the role that melatonin production plays in the regulation of sleep consolidation in a population of shiftworkers working and sleeping in their natural environments. 253 locomotive engineers (249 male, 4 female, mean age = 39.7 years) participated in the study for a 2-week period whilst working their normal roster patterns. Participants recorded details for all sleep periods in a sleep diary and collected urine samples during each day's main sleep period. The samples were subsequently assayed for the metabolite of melatonin in urine, 6-sulphatoxymelatonin (aMT6s), and the rate of excretion during main sleep periods was calculated. Separate one-way factorial ANOVAs revealed a significant effect of time of sleep onset on aMT6s excretion rate, sleep duration, and subjective sleep quality. Generally, the rate of aMT6s excretion was lower, sleep duration was shorter, and sleep quality was lower for sleeps initiated during the daytime than for sleep...
Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature
Biological Research For Nursing, 2017
Shift work, especially that involving rotating and night shifts, is associated with an increased risk of diseases, including cancer. Attempts to explain the association between shift work and cancer in particular have focused on the processes of melatonin production and suppression. One hypothesis postulates that exposure to light at night (LAN) suppresses melatonin, whose production is known to slow the development of cancerous cells, while another proposes that circadian disruption associated with shift work, and not just LAN, increases health risks. This review focuses on six studies that employed quantitative measurement of LAN and melatonin levels to assess cancer risks in shift workers. These studies were identified via searching the PubMed database for peer-reviewed, English-language articles examining the links between shift work, LAN, and disease using the terms light at night, circadian disruption, health, risk, cancer, shift work, or rotating shift. While the results indi...
Excessive Daytime Sleepiness in Firefighters in the Central United States
Journal of Occupational and Environmental Medicine, 2013
Objective: To determine the prevalence and severity of excessive daytime sleepiness (EDS) in a population-based sample of firefighters. Methods: Sleepiness was assessed using the Epworth Sleepiness Scale in a sample of male career firefighters (n = 458) from 11 randomly selected fire departments in the Midwestern United States. Results: Unadjusted EDS rates (13.7% and 14.0% for on-and off-duty, respectively) were similar to the general US population and comparable occupational groups. Factors associated with EDS included 48-hour work shifts, non-private department sleep areas, and working a second job outside the fire service (P < 0.05). Conclusion: Given firefighters' important role in public safety, concerns have been raised about whether firefighters' work schedules result in high rates of excessive sleepiness. Nevertheless, firefighters in this study did not have high rates of EDS despite their extended work schedule.