Cognitive functioning of female nurses during the night shift: The impact of age, clock time, time awake and subjective sleepiness

Abstract

Decline in cognitive functioning in the workplace is a major concern for health care systems. Understanding factors associated with nighttime functioning is imperative for instituting organizational risk management policies and developing personalized countermeasures. The present study aims to identify individual factors associated with cognitive functioning during the night shift of hospital nurses working on irregular rotating-shift schedules. Ninety-two female nurses were recruited from 17 wards in two general hospitals, using convenience sampling by clusters. Inclusion criteria were working at least 28 h a week (75% of full time) and one night shift per week. Exclusion criteria were pregnancy, diagnosed sleep disorders or medical conditions that may affect sleep and/or function. Cognitive performance was measured during the middle (03:00 h) and at the end (07:00 h) of the night shift using the Digit Symbol Substitution Task (DSST) and the Letter Cancellation Task (LCT) over two night shifts. Subjective sleepiness was assessed by the Karolinska Sleepiness Scale (KSS) at the same time points. All participants completed a sociodemographic questionnaire, the Munich ChronoType Questionnaire for Shift-Workers (MCTQShift) and the Pittsburgh Sleep Quality Index (PSQI). Sleep duration 24 h before the night shift and time awake since last sleep opportunity were monitored by actigraphy. Univariate repeated measures ANOVA found main effects for clock time (p<0.001), age (p<0.05), time awake (p<0.05) and sleepiness (p<0.01) for DSST correct responses; main effects for clock time (p<0.001) and sleepiness (p<0.001) for LCT capacity; and main effects for clock time (p<0.001) and age (p<0.01) for LCT omission errors. All factors remained significant in a mixed-model analysis for DSST. Cognitive performance among hospital nurses is low during the middle of the night shift and increases at the end of the shift; decreased functioning is associated with increased subjective sleepiness, older age and prolonged time awake. Identifying factors contributing to performance during the night shift may provide a basis for the development of risk management policies and preventative interventions.

Let them sleep: The effects of a scheduled nap during the night shift on sleepiness and cognition in hospital nurses

“…While omission errors reflect accuracy, the number of correct responses on the DSST and LCT capacity reflect performance speed. Thus, the authors speculate that the speed aspect of visuomotor performance tasks is especially influenced by homoeostatic sleep drive (Zion & Shochat, ) and, therefore, that a short nap aimed to offset this influence may benefit performance speed more than accuracy. These findings are consistent with those of other field studies showing improved speed performance on vigilance tasks following a short nap during the night shift (Purnell, Feyer, & Herbison, ; Signal, Gander, Anderson, & Brash, ; Smith et al, ; Smith‐Coggins et al, ).…”

“…The authors previously demonstrated biopsychosocial factors that are associated with night shift sleepiness and performance (Zion et al, ; Zion & Shochat, ). The current study shows that the effects of a scheduled nap on sleepiness and performance are significant above and beyond the effects of biopsychosocial factors that are independently associated with night shift performance.…”

“…Furthermore, the authors previously reported several factors associated with sleepiness and performance during the night shift (Zion, Drach‐Zahavy, & Shochat, ; Zion & Shochat, ). Older shift workers were more vulnerable to the negative impacts of night work on cognitive performance (Bonnefond et al, ; Bonnefond, Rohmer, Hoeft, Muzet, & Tassi, ; Tadinac, Sekulić, Hromatko, Mazul‐Sunko, & Ivancić, ), whereas younger workers reported increased sleepiness (Bonnefond et al, ; Härmä, Sallinen, Ranta, Mutanen, & Müller, ; Zion et al, ).…”

Burnout, Sleep, and Sleepiness during Day and Night Shifts in Transition from 8- to 12-Hour Shift Rosters among Airline Ground Crew Managers

“…Furthermore, during the 12-h night shift, nappers took advantage of the opportunity to nap, yet their sleep efficiency at home was compromised. It is likely that individual differences that are associated with adaptation to shiftwork, such as age, chronotype, cognitive arousal, responsibilities, and sleep opportunities at home, may underlie these different adaptation strategies [22,23].…”

Oncology nurses’ compassion fatigue, burn out and compassion satisfaction

“…Nurses who work at night or in rotating shifts rarely have sufficient amounts of sleep. Sleep loss is cumulative, and after a while, the sleep debt may be significant enough to impair integration of information, cloud decision-making, and interrupt planning, plan implementation and vigilance [43]. Insufficient sleep has been associated with mood and cognition changes, lower quality job performance, declined motivation, safety risks and physiological complains [44,45].…”