Sleepiness and Its Peak Time during Shift Work among Nurses Working in Hospital Wards

Abstract

Purpose: The study aimed to examine the actual state of sleepiness and its peak time during shift work (2-shift- and 3-shift-system) among nurses working in hospital wards.

Methods: The participants were 54 nurses (14 male and 40 female, mode age-class 35–44) working in shifts. They were instructed to record their sleepiness and its peak time during shifts in logbooks for four weeks. The obtained data were descriptively analyzed for each shift type.

Results: Data for 320 day shifts and 82 night shifts for the 2-shift system, and 237 day shifts, 111 semi-night shifts, and 120 late night shifts for the 3-shift system were analyzed. Sleepiness was reported in 37–54% day shifts, 47% semi-night shifts, and 68–76% late night shifts. Further, peak time of sleepiness was not dependent on the time elapsed from the start of the shift. Time when sleepiness was more likely to occur was around 3:00–5:00 in late night shifts, 14:00–16:00 in day shifts, and 22:00–23:00 in semi-night shifts, which likely varied according to their biological rhythm.

Conclusion: The peak time of sleepiness did not correlate with the elapsed time since the start of the shift, but seemed to depend on the individual’s circadian rhythm.