Introduction: Poor quality of sleep is a distressing and worrying condition that can disturb academic performance of medical students. Sleep hygiene practices are one of the important variables that affect sleep quality. The objective of this study was to assess association between sleep hygiene practices and sleep quality of medical students in Qazvin University of Medical Sciences. Methods:In this descriptive-correlational study, a total of 285 medical students completed a self-administered questionnaire. Demographic data, sleep-wake schedule in weekday and weekend, and sleep duration were collected. Students' sleep quality was assessed by Pittsburg Sleep Quality Index (PSQI). Data were analyzed by SPSS Ver 13. Results: Overall, 164 (57.5) of students had poor sleep quality. Mean global PSQI score and average score of four subscales were significantly higher in male than female. Regression analysis showed that male students (β=-0.85, P<0.05), students at senior level (β=-0.81, P<0.05), married students (β=-0.45, P<0.05), and those with improper sleep hygiene practices slept worse. Conclusion: The findings of this study showed that the prevalence of poor sleep quality in medical students is high. Improper sleep hygiene behaviors might be a reason for poor quality of sleep in medical students.

The consequences of sleep deprivation and sleepiness have been noted as the most important health problem in our modern society among shift workers. The objective of this study was to investigate the prevalence of sleep disorders and their possible effects on work performance in two groups of Iranian shift workers and nonshift workers. This study was designed as a cross-sectional study. The data were collected by PSQI, Berlin questionnaire, Epworth Sleepiness Scale, Insomnia Severity Index, and RLS Questionnaire. Occupational impact of different sleep disorders was detected by Occupational Impact of Sleep Disorder questionnaire. These questionnaires were filled in by 210 shift workers and 204 nonshift workers. There was no significant difference in the age, BMI, marital status, and years of employment in the two groups. Shift workers scored significantly higher in the OISD. The prevalence of insomnia, poor sleep quality, and daytime sleepiness was significantly higher in shift workers. Correlations between OISD scores and insomnia, sleep quality, and daytime sleepiness were significant. We concluded that sleep disorders should receive more attention as a robust indicator of work limitation.

Workers’ fatigue is a significant problem in modern industry, largely because of high demand jobs, long duty periods, disruption of circadian rhythms, and accumulative sleep debt that are common in many industries. Fatigue is the end result of integration of multiple factors such as time awake, time of day, and workload. Then, the full understanding of circadian biologic clock, dynamics of transient and cumulative sleep loss, and recovery is required for effective management of workplace fatigue. It can be more investigated in a new field of sleep medicine called occupational sleep medicine. Occupational sleep medicine is concerned with maintaining best productivity and safety in the industrial settings. The fatigue risk management system (FRMS) is a comprehensive approach that is based on applying scientific evidence of sleep knowledge to manage workers fatigue. It is developing rapidly in the highly safety demand jobs; especially truck drivers, pilots, and power plant workers. The objective of this review is to explain about fatigue in the workplace with emphasis on its association work performance and errors/accidents. Also, we discussed about different methods of fatigue measurement and management.

Background: Night work is associated with disturbed sleep and wakefulness, particularly in relation to the night shift. Circadian rhythm sleep disorders are characterized by complaints of insomnia and excessive daytime sleepiness that are primarily due to alterations in the internal circadian timing system or a misalignment between the timing of sleep and the 24-h social and physical environment.

BACKGROUND: Morningness and eveningness preference (chronotype), an endogenous component of the circadian clock could play a key role in a worker's ability for adjusting to shift work. Morning types are those individuals who prefer going to bed and waking up early, whereas Evening types tend to sleep at later hours and find it difficult to get up in the morning. OBJECTIVE: The objective of this study was to survey, the relationship between morningness-eveningness type, sleep quality and insomnia in shift worker nurses. PARTICIPANTS: The participants comprised 160 nurses working in three different wards in two university hospitals in Iran. METHODS: Nurses completed the Horne and Ostberg [23] questionnaire to assess the distribution of morningness or eveningness preference, the Pittsburg Sleep Quality Index [22] and Insomnia Severity Index questionnaire [21] to measure self reported sleep quality and insomnia. Demographic information was also collected in order to explore the relationship between circadian rhythms, sleep quality and prevalence of insomnia in shift workers. RESULTS: The results showed that the prevalence of poor sleep quality was high. More than half of the participants had poor sleep. Evening type nurses had worse sleep quality in our study (P < 0.05). There is not any significant association between the shift type and age of the nurses with their quality of sleep (P > 0.05). CONCLUSIONS: The results suggested that nurses who had a morning sleep preference had better sleep quality. A survey of chronotype of nurses could be useful, so that individuals may be assigned to different shifts according to their sleep preference.