Sleepiness and driving events in shift workers: the impact of circadian and homeostatic factors. Issue 6 (18th March 2019)

• Record Type: Journal Article
• Authors: Mulhall, Megan D; Sletten, Tracey L; Magee, Michelle; Stone, Julia E; Ganesan, Saranea; Collins, Allison; Anderson, Clare; Lockley, Steven W; Howard, Mark E; Rajaratnam, Shantha M W
• Is Part Of: Sleep. Volume 42:Issue 6(2019)
• Publication Date: 2019-03-18
• Subjects: shift work -- driving -- sleep -- wakefulness -- homeostatic -- circadian -- alertness; Sleep -- Physiological aspects -- Periodicals; Sleep disorders -- Periodicals; Sommeil -- Aspect physiologique -- Périodiques; Sommeil, Troubles du -- Périodiques; Sleep disorders; Sleep -- Physiological aspects; Sleep -- physiological aspects; Sleep Wake Disorders; Psychophysiology; Electronic journals; Periodicals; 616.8498
• DOI: 10.1093/sleep/zsz074
• Languages: English
• ISSNs: 0161-8105

Abstract

Abstract: We aimed to characterize objective and subjective sleepiness and driving events during short work commutes and examine the impact of circadian and homeostatic factors across different shift types in a shift worker population. Thirty-three nurses were monitored for 2 weeks over day (07:00–15:30), evening (13:00–21:30), and night shifts (21:00–07:30). Sleep was measured via daily sleep logs and wrist actigraphy. Driving logs were completed for each work commute, reporting driving events and a predrive Karolinska Sleepiness Scale (KSS). Ocular data from a subset of participants ( n = 11) assessed objective sleepiness using infrared oculography during commutes. Circadian phase was assessed at three time points via urinary 6-sulphatoxymelatonin (aMT6s) collected over 24–48 hours. Subjective and objective sleepiness and sleep-related and hazardous driving events significantly increased following night shift compared with preshift. There were significant shift differences with KSS, sleep-related and inattention-related events highest during the postnight shift commute, compared with day and evening shifts. Sleep-related events were highest following the first night shift, while inattention-related events were most frequent after consecutive night shifts. KSS, sleep-related and hazardous events were increased during drives following ≥16 hours of wakefulness. KSS and sleep-related events increased during drives within ±3 hours of aMT6s acrophase. An interaction between homeostatic and circadian processes was observed, with KSS and sleep-related events highest within ±3 hours of acrophase, when wakefulness was ≥16 hours. In naturalistic conditions, subjective and objective sleepiness and driving events are increased following night shifts, even during short (~30 minutes) commutes and exacerbated by an interaction between circadian phase and duration of wakefulness.