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Updated: Sep 5, 2025

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
The circadian preference to operate electively among surgeons: A cross-sectional study
Khalid Arab1, Hatan Mortada2, Subhi M K Zino Alarki2
1Department of Surgery, Division of Plastic Surgery, King Saud University, Riyadh, Saudi Arabia.
Background:
The circadian rhythm is unique to each individual. The time of the day when an individual is most productive is determined by several factors associated with circadian rhythm. Some evidence suggests that late-night surgeries are associated with a better prognosis and a lower rate of complications than those performed at other times of the day. However, the impact of surgeons' preferred operating time on patients remains unclear.
Objective:
The present study is the first to examine at what time of the day surgeons prefer to operate.
Methods:
This cross-sectional, questionnaire-based study involved 15 items designed to interrogate surgeons' preferred time of day to operate. The questionnaire was distributed electronically to the consultants of different surgical specialties after explaining the purpose of the study and obtaining their consent to participate.
Results:
A total of 226 surgeons participated in this study, of which 192 (85%) were men. Most (25.2%) consultants were general surgeons. The weekly workload for most (66.4%) surgeons was 41-60 h. The surgeons indicated their preference to operate in the early (11.9%) or late morning (71.2%), early (15.0%) and late (1.3%) afternoon, and evening (0.4%). The key determinant of their preference was the availability of hospital resources (36.3%). Men and women tended to prefer operating in the early morning and afternoon and late afternoon, respectively.
Conclusions:
In the present study, most surgeons preferred to operate between 8 am and 12 noon (late morning), and their preference was determined by the availability of hospital resources.
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