The impact of alcohol hangover and total sleep time on simulated highway driving

Introduction: An evening out consuming alcohol often occurs at the expense of sleep time. The purpose of this study was to investigate the effects of alcohol hangover on driving performance, and to examine the mediating properties of sleep time on hangover related performance impairment. Methods: N = 42 healthy volunteers conducted a 100-km simulated highway driving test the morning following an evening of consuming on average 10.2 (4.2) alcoholic drinks (alcohol hangover) and on a control day (no alcohol consumed). Subjects performed the simulated highway driving test when blood alcohol concentration (BAC) was zero. Standard Deviation of Lateral Position (SDLP, i.e. the weaving of the car) and lapses in driving were measured. A lapse was deined as a change of lateral position of > 100 cm for at least 8 seconds. ΔSDLP (hangover - control) and Δlapses were related to total sleep time. Performance as compared between subjects who slept less than 5 hours, 5 to 7 hours, and more than 7 hours. Results: A signiicant increase in both SDLP (+1.9 cm, p = 0.007) and the number of lapses (+2.4, p = 0.019) was observed during alcohol hangover. Relative to the control day, total sleep time was signiicantly reduced by on average 120 minutes in the alcohol hangover condition. Total sleep time had a moderating effect on ΔSDLP (hangover - control), in that subjects who slept less than 5 hours showed a larger ΔSDLP than those who slept 5 to 7 hours or more than 7 hours (+3.3 cm, +1.0 cm, and -0.1 cm, respectively). A reduced impact on driving performance was not seen when looking at Δlapses of the different sleep duration groups (+2.3, +2.8, and +1.8, respectively). Conclusion: Driving is signiicantly impaired during alcohol hangover, with the magnitude of driving impairment being moderated by sleep duration.