Impaired self-monitoring ability on reaction times of psychomotor vigilance task of nurses after a night shift

The cognitive ability to self-monitor one's current performance is important for hospital nurses to maintain safety and health. However, studies on the effects of rotating shift work on self-monitoring ability are insufficient. We examined the differences in self-monitoring accuracy across shifts in a rotating three-shift system among 30 female ward nurses (mean age 28.2 years). Their self-monitoring ability was calculated by subtracting the predicted reaction times of the psychomotor vigilance task performed just before exiting the workplace from the actual reaction times. A mixed-effect model was employed to assess the effects of shift, awake hours, and prior sleep duration on self-monitoring ability. We observed impaired self-monitoring ability in nurses, particularly after the night shift. Although actual performance remained high across all shifts, their self-predictions on reaction times became pessimistic in the night shift, resulting in a difference of approximately-100 msec. The effect of the shift on self-monitoring was obvious even after adjusting for sleep duration and hours awake. Our findings indicate that the misalignment between their working hours and circadian rhythms may affect even professional nurses. Occupational management that emphasizes maintaining circadian rhythms will improve the safety and health of nurses.