The effects of a scheduled nap during the nightshift on performance, sleepiness and vigor in nurses

Abstract

Nighttime shift-work has been found to be a culprit of negative consequences in terms of safety and performance. In nurses, these consequences also pose a threat to the care and safety of patients. Evidence suggests that a scheduled nap may be an effective countermeasure. However little is known about the effects of a brief planned nap on measures that reflect the performance of nurses during the actual night shift. This field study aimed to examine the effectiveness of a planned nap during the nadir of alertness, on cognitive performance, evaluation of duty transfer, and self- reported sleepiness and vigor, in nursing staff working eight hour night shifts in the hospital. In this prospective, within subjects experimental study design, thirty female and male nurses working shifts were recruited by cluster sampling from several hospital wards at Bnei Zion Medical Center in Haifa. All nurses had an appointment of 75% and above and worked at least one night shift per week. Nurses who were pregnant, had a diagnosed sleep disorder or chronic medical condition that could affect sleep or functioning, were excluded. The study protocol was conducted in the course of nurses’ usual work schedule, and included two nights with and two nights without a nap, intermittently. Cognitive testing, performed at 06:30, included the Letter Cancellation task (LCT) and the Digit Symbol Substitution Task (DSST). At 07:00, they transferred the shift to the head nurse of the department, who completed a written evaluation of the duty transfer and was blinded to the experimental condition. During planned nap nights, nurses went to sleep in a dark quiet room at 04:00 for 30 min, and on non-nap nights they continued to work as usual. To monitor sleep patterns and duration, nurses wore an actigraph 24-h before and during the night shift. Compared to non-nap nights, performance measures were significantly higher on the LCT ( p < 0.05), and tended to be higher on the DSST ( p < 0.08), and evaluation of duty transfer was improved ( p < .05) on nap nights. Levels of sleepiness were lower at 05:00, 06:00 and 07:00 and measures of vigor were higher at 05:00 and 07:00 on nap vs. non-nap nights ( p < 0.01). A planned nap is an effective, cheap and simple strategy to improve occupational safety and performance of the nursing staff and to improve the safety and quality of patient care. The study is supported by a grant from the Israel Ministry of Industry, Trade and Labor .