Article Text

Download PDFPDF
Driving impairment due to sleepiness is exacerbated by low alcohol intake
  1. J A Horne,
  2. L A Reyner,
  3. P R Barrett
  1. Sleep Research Centre, Loughborough University
  1. Correspondence to:
 Professor J A Horne, Sleep Research Centre, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK; 
 j.a.horne{at}lboro.ac.uk

Abstract

Aims: To assess whether low blood alcohol concentrations (BACs), at around half the UK legal driving limit, and undetectable by police roadside breathalysers, further impair driving already affected by sleepiness, particularly in young men, who are the most “at risk” group of drivers for having sleep related crashes.

Methods: Twelve healthy young men drove for two hours in the afternoon, in an instrumented car on a simulated motorway. In a repeated measures, counterbalanced design, they were given alcohol or placebo under conditions of normal sleep or prior sleep restriction. Measurements were: driving impairment (lane drifting), subjective sleepiness, and EEG measures of sleepiness.

Results: Whereas sleep restriction and alcohol each caused a significant deterioration in all indices, the combined alcohol and sleep restriction further and significantly worsened lane drifting (which typifies sleep related crashes). This combined effect was also reflected to a significant extent in the EEG, but not with subjective sleepiness. That is, alcohol did not significantly increase subjective sleepiness in combination with sleep loss when compared with sleep loss alone.

Conclusions: Modest, and apparently “safe” levels of alcohol intake exacerbate driving impairment due to sleepiness. The sleepy drivers seemed not to have realised that alcohol had increased their sleepiness to an extent that was clearly reflected by a greater driving impairment and in the EEG.

  • sleepiness
  • alcohol
  • driving
  • BAC, blood alcohol concentration
  • BMI, body mass index
  • EEG, electroencephalogram
  • EOG, electro-oculogram

Statistics from Altmetric.com

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Footnotes