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Vangelova K., Cekova I., Dimitrova I.


National Center of Public Health and Analyses, Sofia, Bulgaria

Full article (PDF), ENG

Introduction. Sufficient and good quality sleep is crucial for shift workers because of its implications on performance and health. The aim of the study was to follow the effects of night shifts and overtime work on sleep and fatigue of hospital physicians in Bulgaria.

Methods.The study was cross-sectional and comprised 719 physicians, 429 female and 291 male, of average age (44.4 ± 14.2) years from Sofia hospitals. Anonymous questionnaire survey included Karolinska Sleep Diary, demographic information, work place variables, working hours and shift system. The statistical analyses were carried out with SPSS.

Results. 26 % of the physicians worked only in day shifts, 55 % from 1 to 4 night shifts, and 28 % more than 5 night shifts. Great deal of the physicians worked more than 40 hours weekly as follows: 38 % worked 41–50 hours per week, 27 % – 51–60 hours and 14 % > 61 hours. The quality of sleep, estimated by SQI was worse with the increase of the number of night shifts (F = 4.260, p = 0.01) and sleep duration and insufficiency of sleep with increase of the hours worked weekly.

Discussion. Shift working with more night shifts monthly and overtime hours weekly contributed to impaired sleep in the studied group of physicians. The sleep impairment was more evident within the increase in the number of night shifts.

Key words: Night shifts, overtime, sleep quality index


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ORCID ID of co-authors and their contribution in preparation and writing of the paper:

Vangelova K.K. (ORCID ID 0000-0003-4702-3130): defining the purpose and design of the study, analyzing the results received, formulation of the conclusions, design and writing of the article.

Cekova I.V. (ORCID ID 0000-0002-9777-2028): conducting the study, review of literature on the paper subject, statistical processing, analysis of the data received.

Dimitrova I.D. (ORCID ID 0000-0001-5394-4783): conducting the study, review of literature on the paper subject, statistical processing, analysis of the data received.