Citation

Duchon JC, Smith TJ, Keran CM, Koehler EJ. Int. J. Ind. Ergonomics 1997; 20(1): 39-49.

Copyright

(Copyright © 1997, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Working extended workshifts and overtime has been linked to three basic manifestations of fatigue, involving decrements in behavioral performance and physiological function, plus subjective complaints. Fatigue, in turn, may be associated with performance decrements and accidents. This report describes findings from a prospective study of changes in an array of subjective response and objective performance measures, before and after workers in an underground mine converted from an 8 h to a 12 h rotating shift schedule. The study employed a psychophysiological approach to work schedule evaluation. An array of putative fatigue-related measures were collected, encompassing pre-, mid-, and post-shift measures of cognitive and psychomotor behavioral performance, estimated maximal oxygen uptake (VO2max) and heart rate (HR) recovery levels using submaximal exercise testing, and subjective self-report mood and sleepiness responses. Continuous heart rate records during work activity across the shift also were collected. There are no significant main effects of schedule (8 h versus 12 h) for most measures. However, the continuous HR findings suggest pacing of work effort on 12 h relative to 8 h shifts. Pre- to post-shift changes in HR recovery and in mood self-report responses are consistent with differential fatigue effects of 12 h relative to 8 h shifts. Results support the conclusion that the extended workdays schedule evaluated in this study is not associated with pronounced fatigue effects, possibly because of moderation of work effort across 12 h compared with 8 h shifts. Relevance to industryUse of extended workdays is becoming more popular in various industries. However, there currently is little information available that allows objective prediction of risks and benefits associated with the use of extended workdays, particularly in physically demanding environments. This study was designed to provide such information by assessing possible differential performance effects of fatigue associated with 12 h versus 8 h workshifts during underground mining work.