Lunch Time Drinking Impairs Driving
Aug. 20, 2003 -- Indulging in as little as one cocktail or glass of wine at lunch could make driving dangerous -- even if the driver has blood alcohol levels within legal limits.
A new study shows just a small amount of alcohol can worsen daytime drowsiness and increase the risk of an accident.
Researchers say most drivers who have a lunchtime drink may not even be aware that a single drink can affect their driving skills, and the dangers of daytime drinking and driving are even more pronounced in people who did not get a good night's sleep.
Researcher Jim Horne, of the Sleep Research Centre at Loughborough University, U.K., and colleagues say about one in 10 road accidents are caused by drowsy drivers, and that rate is even higher on long stretches of highway.
For the study, published in the current issue of Occupational and Environmental Medicine, researchers tested the driving alertness of 12 men between the ages of 20 and 26, which is an age group at high risk of automobile accidents.
The men had either a normal night's sleep or a night of disrupted sleep. Their driving skills were tested after they had a drink with lunch -- either an orange juice and vodka cocktail or alcohol-free drink. The participants didn't know whether or not they drank an alcoholic -- 2.5 ounces of alcohol -- or non-alcoholic drink. Each man was then asked to drive for two hours in a driving simulator.
Researchers looked at the amount of lane drift among the drivers, their perceived levels of sleepiness, and electrical brain activity measured by EEG (electroencephalography).
They found daytime drinking worsened the body's natural dip in mental alertness that occurs in the afternoon in non-sleepy drivers and even more so in sleepy drivers. In particular, alcohol significantly increased the amount of lane drift, which is a common cause of accidents involving drowsy drivers.
But the drivers themselves did not seem to notice the additional effect of alcohol on their sleepiness.
Researchers say those findings suggest that mixing even one drink with driving is dangerous and could lead to an accident, and sleepy drivers should avoid alcohol at all times, if not avoid driving altogether.