Cognitive consequences of sleep deprivation, shiftwork, and heat exposure for underground miners

Glenn Legault; Alexandra Clement; Glen P Kenny; Stephen Hardcastle; Nancy Keller

doi:10.1016/j.apergo.2016.06.007

Cognitive consequences of sleep deprivation, shiftwork, and heat exposure for underground miners

Appl Ergon. 2017 Jan:58:144-150. doi: 10.1016/j.apergo.2016.06.007. Epub 2016 Jun 25.

Authors

Glenn Legault¹, Alexandra Clement², Glen P Kenny³, Stephen Hardcastle⁴, Nancy Keller⁵

Affiliations

¹ Center for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada. Electronic address: glegault@laurentian.ca.
² Center for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada.
³ Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.
⁴ CanmetMINING, Natural Resources Canada, Sudbury, ON, Canada.
⁵ Occupational Health and Medicine Sustainability, Vale, Sudbury, ON, Canada.

PMID: 27633207
DOI: 10.1016/j.apergo.2016.06.007

Abstract

Sleep deprivation, abnormal sleep patterns arising from working rotating shifts, and exposure to high ambient temperatures contribute to physical and cognitive dysfunction. We examined the effects of these on 19 (41.5 ± 5.1 years) male underground miners. Data were collected for 28 to 30 consecutive days such that the participants experienced their full rotating shift schedule, including days off. Objective measures of sleep quality (actigraphy), attentional capacity (psychomotor vigilance task), core body temperature (visceral pill), executive function (BRIEF-A) and subjective measures of fatigue (Karolinska and Epworth Sleepiness scales) were obtained over the 28-30 day period. Non-parametric analyses (χ(2), Wilcoxen Signed ranks) were used to determine differences between shift types and days off. Z-tests were used to compare sample data to population norms. These revealed that the participants experienced poor quality of sleep relative to age-matched norms irrespective of the shift being worked or if the participant was on a scheduled day off [30-39 year olds: z = -14.62, p < 0.001; 40-49 year olds: z = -4.44, p < 0.001]. Participants when working day shift experienced less sleep prior to beginning work compared to their days off or night shift; however, no differences in total sleep time between when participants worked day or night shifts were observed [χ(2) (2, n = 18) = 13.44, p < 0.01]. When measured subjectively, the only time participants reported excessive sleepiness was after a night shift. Objective measures of attentional capacity showed best performance at the beginning of night shifts in contrast to any other time that the task was completed; however, performance degraded dramatically over the course of the night shift [χ(2) (2, n = 12) = 6.50, p < 0.05]. We show that underground miners reported for work sleep deprived. The cognitive consequences of this poor sleep were most pronounced during night shift when their attentional capacity declined rapidly over the course of the night shift.

Keywords: Cognition; Fatigue; Heat exposure; Sleep deprivation.

MeSH terms

Actigraphy
Adult
Attention
Body Temperature
Cognition
Cognitive Dysfunction / etiology*
Executive Function
Fatigue / etiology
Hot Temperature / adverse effects*
Humans
Male
Middle Aged
Mining*
Occupational Diseases / etiology*
Psychomotor Performance
Sleep
Sleep Deprivation / psychology*
Work Schedule Tolerance / psychology*