The effects of task duration and work-session location on performance degradation induced by sleep loss and sustained cognitive work

Studies attempting to estimate the degree of performance degradation resulting from sleep loss typically use relatively long-duration tasks that are distinctly separate from ongoing activities. Since long-duration tasks are not practical for assessing the performance degradation induced by sleep loss in field settings, this study was designed to examine whether the results of short-duration (1-min) tasks were markedly different from those of long-duration (10-min) tasks with respect to detecting performance changes during a 54-h period of sleep loss and sustained cognitive work. Performance changes also were examined as a function of the location of tasks within work sessions by comparing performance on 1-min tasks that were placed within work sessions with those tasks that immediately followed short rest periods. The results showed that short-and long-duration tasks were equally sensitive to sleep loss. In addition, once sleep-deprivation effects began to emerge, it was found that performance on short-duration tasks within work sessions showed significantly more impairment than performance on tasks that followed rest breaks. These results suggest that task duration is not a critical factor for detecting performance degradation induced during continuous work experiments but that the location of tasks within work sessions is critical for accurately assessing expected performance.