Perceived level of performance impairment caused by alcohol and restricted sleep

• Investigated perceptions of performance ability following alcohol and wakefulness.
• People consider the ability to perform tasks after sleep deprivation as most impaired.
• Assessed performance level is positively related to amount of sleep.
• Assessments of transport activities were lower than of non-transport activities.

The aim of the current study was to investigate people’s perceptions towards the ability to perform various tasks (transport-related and other tasks) under the influence of alcohol and prolonged wakefulness. We assumed that people will assess that after alcohol consumption performance is damaged more than after sleep restriction. In addition we assumed that participants will relate performance impairment to the level of sleep loss. Participants (525 men and 620 women) were asked to refer to eighteen descriptions of imaginary situations (scenarios) where someone was asked to perform a duty under a certain awareness condition either after alcohol consumption or after total or partial sleep restriction (four levels). Of the eighteen scenarios, three were related to transport safety such as ambulance driver, a traffic policeman and a pilot. Participants were asked to rate the degree of fitness of the described person in each scenario on a 0–100 scale. The results show that people considered the ability to perform various tasks after absolute sleep restriction as more impaired than in other conditions, with alcohol as second worse, followed by performing after the conditions of partial sleep restriction. Also, it has been found that more sleep was related to better performance. Within life threatening tasks, the alcohol and sleep restriction conditions did not differ in ratings and were significantly lower than each one of the sleep conditions. Furthermore, transportation activities were assessed as more impaired than non-transport activities after alcohol consumption and no sleep but less impaired than non-transport activities after restricted sleep.