Investigating the effect of night shifts rotation speed on the pattern of melatonin secretion and sleepiness among petrochemical control room operators

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 sleepiness was not significant (P <0.05). Moreover, a significant difference was observed between the process of melatonin changes and sleepiness in the two studied patterns (P <0.05). Conclusion: Adopting slower shift schedules rotations would be more appropriate, from the viewpoints of the importance of alertness and performance for human error prevention, among people working in serious worksites such as control rooms.