Effect of sleep deprivation on self-selected workload

Psychophysical methods have been used successfully to establish maximal acceptable loads (MALs) in industrial repetitive lifting tasks, and it is known that physical tasks remain relatively unaffected by sleep deprivation, whereas cognitive tasks may be significantly degraded.

Abstract

Abstract Psychophysical methods have been used successfully to establish maximal acceptable loads (MALs) in industrial repetitive lifting tasks, and it is known that physical tasks remain relatively unaffected by sleep deprivation, whereas cognitive tasks may be significantly degraded. Since the psychophysical method is essentially a physical task yet has a cognitive element (in that subjects are required continuously to reassess their decisions concerning MAL based upon their perceptions of the load weight), it was not known whether MAL would remain unchanged or be degraded by sleep deprivation. Consequently, two groups of soldiers (a sleep-deprived and control group) were studied over a 3 week period. After 5 training days, a week-end and 2 baseline days, the sleep-deprived group were partially sleep deprived for 3 days and then totally sleep deprived for 2 days, whilst the control group were allowed 4 hours uninterrupted sleep daily. There followed 1 day during which the subjects were allowed to sleep as they felt necessary, and 2 days of recovery measurements. There was no statistically significant difference in MAL between the two groups, nor in the pattern of load adjustment adopted by the subjects. It is concluded that the assessment of MAL, using psychophysical methods, is uninfluenced by sleep deprivation.