Sleep, alertness and performance across a first and a second night shift in mining haul truck drivers

ABSTRACT

This study examined the impact of first and second night shift work on sleep and performance in mining haul truck drivers. Sleep-wake patterns were monitored using wrist actigraphy. The Karolinska Sleepiness Scale (KSS), Psychomotor Vigilance Test (PVT) and a truck simulator were administered at the start and end of the first (N1) or second (N2) night shift (19:00–07:00 h). Participants were categorised into those who demonstrated a decline in performance (increase of one or more PVT lapses [reaction time >500 msec] from the start to the end of shift) or those who did not demonstrate a decline in performance (no increase in lapses) from the start to the end of shift. Total sleep time (TST) was longer in the 24 h prior to N1 (9.05 ± 1.49 h) compared to N2 (5.38 ± 1.32 h). PVT lapses and the slowest 10% of reaction times were similar at the start and end of N1, while greater impairments on these outcomes were observed at the end of N2 compared to the end of N1 (p < .05). In contrast, subjective sleepiness was equally impaired at the end of both night shifts. PVT performance (lapses and slowest 10% of reaction times) and drive violations demonstrated a similar direction of change on N1 and N2. Participants who demonstrated a decline in performance showed reduced TST in the 48 h prior to shifts compared to those who demonstrated no decline in performance across the shift. Likely due to short sleep prior, the end of N2 was associated with pronounced performance impairments on the PVT and drive violations compared to the start of the shift. The findings suggest that drive violations may be more sensitive to sleep loss compared to the other driving measures examined in this study. This study also emphasizes the need for adequate recovery sleep between night shifts.

KEYWORDS:

• Sleep loss
• vigilance
• night work
• mining
• safety
• napping

Acknowledgements

The authors thank the occupational health and safety team at the mining site for assisting with participant recruitment, the staff for participating in the study and A/Prof. Steven W. Lockley for contributing to the development of this manuscript.

Disclosure statement

Ms Ganesan has no conflicts to declare. Dr Manousakis reports receiving contract research funding from the Department of Transport, Victoria and the Automobile Association of Australia for work not related to this manuscript. Dr Mulhall is an employee of Seeing Machines Ltd in a capacity not related to this manuscript. Dr Sletten serves as a Project Leader in the Cooperative Research Centre (CRC) for Alertness, Safety and Productivity and has received grants from Teva Pharmaceuticals, and Qantas Airways, and equipment support and consultancy fees through her institution from Philips Respironics, Vanda Pharmaceuticals, and Seeing Machines which are not related to this paper. Dr Tucker serves as a Program Leader in the Cooperative Research Centre (CRC) for Alertness, Safety and Productivity; and reports grants from BHP, Shell and VicRoads, which are not related to the work reported in this paper. Dr Howard serves as a Theme Leader in the CRC for Alertness, Safety and Productivity; and has received grants from Prevention Express, Shell and VicRoads, and equipment support and consultancy fees through his institution from TEVA Pharmaceuticals, Sanofi, Philips Respironics, Optalert and Seeing Machines which are not related to the work reported in this paper. Dr Anderson has received a research award/prize from Sanofi-Aventis and research support from VicRoads/Department of Transport, Victoria, Pacific Brands, Rio Tinto, CogState Ltd, Seeing Machines Ltd; speaker fees from, Ausmed, Healthed, and Teva Pharmaceuticals; and consultancy fees from Rail, Bus and Tram Union, National Transport Commission, the Transport Accident Commission, and Melius Consulting. She was a Theme Leader in the Alertness CRC at the time of this work. Dr Rajaratnam reports grants from Vanda Pharmaceuticals, Philips Respironics, Cephalon, Rio Tinto and Shell, and has received consultancy fees through his institution from Alertness CRC, Teva Pharmaceuticals, Vanda Pharmaceuticals and Circadian Therapeutics which are not related to this paper. Dr Rajaratnam serves as Chair of the Sleep Health Foundation.

Supplemental data

Supplemental data for this article can be accessed on the publisher’s website.

Data availability statement

Materials and data in this publication can be requested by emailing [email protected].

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Funding The original study that supported data collection was funded by the company that employed the participants. The current analysis was outside the scope of the original study and was supported by a Faculty Graduate Research International Scholarship from Monash University.