Annals of Tropical Medicine and Public Health
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Year : 2017  |  Volume : 10  |  Issue : 3  |  Page : 595-599

Effects of bright light shock on sleepiness and adaptation among night workers of a hospital in Iran

1 Department of Occupational Health Engineering, School of Health, Zabol University of Medical Sciences, Zabol, Iran
2 Department of Physiology, School of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran
3 Occupational and Environmental Health Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
4 Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah; Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
5 Social Determinants of Health Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
6 Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran
7 Master of Economic Development and Planning, University of Firoozkooh Branch, Islamic Azad University, Firoozkooh, Iran
8 Department of Ergonomics, School of Rehabilitation, Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran

Correspondence Address:
Mohsen Poursadeghiyan
Department of Ergonomics, Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ATMPH.ATMPH_108_17

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Background: Night work has many harmful effects on health, efficiency, and industrial safety of workers. Night workers often complained of sleepiness, decrease of performance, and sleep disorder due to the lack of circadian influence that fully encourages night orientation. Objective: This research was conducted in an industrial environment and it accessed the effects of bright-light (BL) exposure on sleepiness during night work. Materials and Methods: This is an interventional study with a cross-over design. A total of 140 night workers with an experience of >1 year at a hospital participated voluntarily in this study. The night workers were divided into two groups, and both groups were exposed to either BL (3000-3500 lux) or normal light (NL) (400 lux) during break times at night work for two consecutive nights. Results: The 15-minute breaks were initiated at 22:00 (before starting work), 24:00, 2:00, and 4:00 h. The range of sleepiness was assessed by the Karolinska Sleepiness Scale (KSS) at 23:00, 1:00, 3:00, and 5:00 h. We used SPSS16 software for data analysis. The results obtained using the paired t-test analysis (P < 0.000) demonstrated that there were significant differences in the rate of sleepiness between the two groups (case and control). Conclusion: The findings of the present study have also demonstrated the feasibility and benefits of photic stimulation in industrial settings which increased the adaptation to night work.

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