A quantitative model of work-related fatigue: empirical evaluations

Systematic and quantitative management of work-related fatigue within work-places has been a challenging task due to a lack of useful tools. A previous paper provided background and development of a work-related fatigue modelling approach. The current paper outlines model evaluations using sleep deprivation experiments and recommendations of work scheduling. Previous studies have reported cumulative effects of sleep restriction (4-5 h per night) on a number of measures. Model predictions were correlated against psychomotor vigilance task lapses (r = 0.92) and reaction time responses (slowest 10%, r = 0.91) as well as sleep latency (r = -0.97). Further correlations were performed on four measures from a 64 h continuous sleep deprivation study; that is objective vigilance (r = -0.75) as well as subjective performance (r = -0.75), sleepiness (r = 0.82) and tiredness (r = 0.79). Evaluation against current scheduling recommendations illustrated consistency with the literature with the exception that forward rotation did not provide benefits over backward rotation. The results indicate that model predictions correlate well across a range of objective and subjective measures. This relationship also appears to hold for cumulative and continuous sleep deprivation protocols. Future studies will also focus on field-based evaluation.