Physical and Psychological Effects of Drowsiness and Fatigue on Nurses Working 16-Hour Night Shifts without Naps:

The objective of this research is to clarify the burden on fatigued and drowsy on nurses working 16-hour night shifts without naps. To clarify this, nurses working a 16-hour night shift (16-hour group) were compared with those working an 8-hour night shift (8-hour group). The target group consisted of 12 female nurses. Seven of the participants worked an 8-hour group (from 00:00–8:30) and five worked a 16-hour group (from 16:00–09:00). Each nurse was fitted with a heart rate (HR) monitor to facilitate an analysis of heart rate variability (HRV). In addition, feelings of drowsiness and fatigue were measured with the visual analog scale (VAS). The VAS values for feelings of drowsiness and fatigue increased for both groups at dawn. On the other hand fatigue significantly increased more for the 16-hour group than for the 8-hour group. In addition, with the exception of the 07:00 time range, the group working the 16-hour group showed significantly higher HRs as a physical change than did the 8-hour group. During the 07:00 time range, the 8-hour group had a significantly larger increase in LF/HF values than did the 16-hour group. Moreover, HF values significantly increased more for the group on the 16-hour group than the 8-hour group in the 07:00 time range. In conclusion, it became clear from changes in the autonomic nervous system around the 07:00 time range that feelings of drowsiness are stronger for the 16-hour group than for the 8-hour group.