Comparing the sleep status of young nurses working under the two-shift system with the 12- or 16-hour night shift in Japan

We conducted a survey of young nurses working at six hospitals adopting the two-shift system (with the 12- or 16-hour night shift ) to clarify which factors, such as whether or not they sleep influence their drowsiness during the night shift. The subjects were some working with the 16-hour night shift group (n=395) and others working with the 12-hour night shift group (n=78). We conducted a questionnaire survey on the sleep status, before, during, and after the night shift. As the results, the average sleep duration before the night shift was 178.5 minutes in the 12-hour night shift group and 113.6 minutes in the 16-hour night shift group. The rate of people who took a nap before the night shift was significantly greater in those working with the 12-hour night shift group. The rate of people who took a nap during the night shift and their average sleep duration were significantly greater among those working with the 16-hour night shift group. The average duration of daytime sleep after the night shift was 60 minutes in the 12-hour night shift group, while it was 235.2 minutes, significantly longer, in the 16-hour night shift group. Thus, we observed that people working in the 12-hour night shift group coped with their fatigue and drowsiness by taking longer naps before the night shift, while those working the 16-hour night shift group coped by taking longer naps during and after the night shift.