Editing Shift work (section)

== Sleep assessment during shift work ==
A cross-sectional study investigated the relationship between several sleep assessment criteria and different shift work schedules (3-day, 6-day, 9-day and 21-day shift) and a control group of day shift work in Korean firefighters.<ref name=":6">{{Cite journal|last1=Jeong|first1=Kyoung Sook|last2=Ahn|first2=Yeon-Soon|last3=Jang|first3=Tae-Won|last4=Lim|first4=Gayoung|last5=Kim|first5=Hyung Doo|last6=Cho|first6=Seung-Woo|last7=Sim|first7=Chang-Sun|date=2019-09-01|title=Sleep Assessment During Shift Work in Korean Firefighters: A Cross-Sectional Study|journal=Safety and Health at Work|volume=10|issue=3|pages=254–259|doi=10.1016/j.shaw.2019.05.003|issn=2093-7911|pmc=6717904|pmid=31497322}}</ref> The results found that all shift work groups exhibited significant decreased total sleep time (TST) and decreased sleep efficiency in the night shift but efficiency increased in the rest day.<ref name=":6" /> Between-group analysis of the different shift work groups revealed that day shift sleep efficiency was significantly higher in the 6-day shift while night shift sleep efficiency was significantly lower in the 21-day shift in comparison to other shift groups (''p'' < 0.05).<ref name=":6" /> Overall, night shift sleep quality was worse in shift workers than those who just worked the day shift, whereas 6-day shift provided better sleep quality compared to the 21-day shift.<ref name=":6" />