Napping and nightshift work: Effects of a short nap on psychomotor vigilance and subjective sleepiness in health workers

Abstract

Nightshift is a common work schedule in health environments, and is associated with decreased alertness and increased adverse events at work. This decrease in alertness can be predicted from biological models of sleep homeostasis and circadian influences. Naps can provide a short-term alleviation of sleep need, and the benefits of naps have been demonstrated in laboratory-based studies, and in specific controlled work environments. The efficacy of brief naps has not been demonstrated in health workers in their usual work environment. The current study examined the effects of a 30-min nap break during the nightshift in a cohort of nursing staff and scientists in their usual work environment. Measures of both subjective sleepiness and objective alertness were taken at hourly intervals throughout the nightshift, on nights where a scheduled nap was taken and nights where there was no nap. Following a nap, psychomotor performance metrics (response speed and fastest 10% reactions times) improved and self-reported sleepiness was reduced compared to nights without a nap. These improvements persisted to the end of the nightshift. Effect size estimates suggested that 20-50% of variance in these measures was explained by the interaction of time on shift and the nap intervention. Differences were found in the timing of increases in subjective and objective alertness after the nap. These findings support the effectiveness of a scheduled nap break during a nightshift to maintain alertness in health workers.

Napping During Night Shift: Practices, Preferences, and Perceptions of Critical Care and Emergency Department Nurses

“…In a study of critical care nurses by Scott et al, 3 the highest frequency of drowsy episodes occurred between 2 AM and 4 AM, with the second highest frequency of episodes reported to occur between 4 AM and 6 AM. Smith and colleagues 49 found that compared with conditions that involved no nap break, night shifts with a nap break were associated with significantly fewer lapses in a vigilance task at 6 AM. Comments from nurses in our study support the difficulties encountered during these periods to remain awake and vigilant.…”

“…In a study 25 of a planned nap for emergency department physicians and nurses, SmithCoggins and colleagues reported that participants in the planned nap group had fewer performance lapses and reported more vigor, less fatigue, and less sleepiness. In a randomized, cross-over study 49 (N = 9), Smith and colleagues report that, compared with a no-nap night shift, a single 30-minute nap break between 2 AM and 3 AM had a significant positive impact on subjective and objective measures of alertness in hospital workers (nurses working in nonacute units and scientists) and that this improved vigilance persisted to the end of the shift. In another study, 50 musculoskeletal pain, and specifically pain in the arm, leg, neck, and shoulder, was lower for 66 nursing home care shift workers (including 11 nurses) who took a nap during night shift on at least half of nights worked compared with persons who took a nap during fewer than half of night shifts.…”

Measures to counteract the negative effects of night work

“…Several studies have shown that naps increase performance on objective measures of sleepiness such as vigilance and time reaction tests (114)(115)(116)(117). Studies on the effects of naps during night work have also shown improvement on measures of subjective sleepiness (114,116,(118)(119)(120).…”

Effects of Napping During Shift Work on Sleepiness and Performance in Emergency Medical Services Personnel and Similar Shift Workers: A Systematic Review and Meta-Analysis

“…The impact of scheduled naps on personnel performance was judged favorable for eight of 11 studies that measured personnel performance (Table 2) (25)(26)(27)(28)(29)(30)(31)(32). Two studies were judged as no impact and one as mixed/ inconclusive for personnel performance.…”

“…Eleven studies evaluated the impact of napping on measures of acute fatigue (25,(27)(28)(29)(31)(32)(33)(34)(35)(36)(37). The impact of napping on acute fatigue (sleepiness) was judged favorable for five of 11 studies, mixed/inconclusive for three studies, and no impact for three studies ( Table 2).…”