Effects of two short naps for nurses working on late-night duty

The purpose of this study was to examine the effects of two 15-min naps on nurses who work at night in three shifts. We requested 16 nurses at municipal hospitals to spend their rest break on a late night shift from 12:00 a.m. to 09:00 a.m. , 8 nurses take two short naps (the first nap at 02:30 a.m. and the second one at 05:00 a.m.:"nap" ) ,and 8 nurses work without taking a nap ("no nap")during on late-night duty. We measured their sublingual temperature, electrocardiogram (ECG), and examined their sleepiness and fatigue levels every hour using a visual analog scale (VAS).The results showed that the temperature for in the morning, "nap" was significantly lower than "no nap" (p<.05), "nap" was similar to a usual circadian rhythm in the temperature. Fatigue and sleepiness in the morning, "nap" maintained the same level as 12:00 a.m. while "no nap" was significantly lower than 12:00 a.m. (p<.05). Furthermore, based on changes in the ECG R-R intervals, "nap" seemed to recovery from fatigue. Thus, these results suggest that night shift nurses take two 15-minute naps, sleepiness and fatigue will be reducing overnight.