Killer hangovers could be just that, according to new research into the effects of driving the day after.
Getting behind the wheel while hungover - even when there is no trace of alcohol in your blood - can be just as dangerous as driving drunk, two studies have found.
International research presented today at the Australasian Professional Society on Alcohol and other Drugs conference, being held in Brisbane, says hangovers can wreak havoc on concentration, reaction time, and general driving ability.
In a Dutch study, people were asked to drive for an hour in a simulation that recreated 100kmh motorway conditions, after downing an average of 10 drinks the night before.
The test began only once each of the 47 participants recorded a zero blood alcohol level. Beforehand, the drivers rated their hangovers out of 10, depending on how thirsty, drowsy, or sore they felt. They also did the same test on a normal day.
Researchers at the Utrecht Institute for Pharmaceutical Sciences found that hung-over people were significantly worse drivers, weaving across the road and losing attention at the same rate as people with an alcohol level of 50 milligrams per 100 millilitres of blood - the limit that New Zealand has recently adopted.
A second study, led by University of the West of England associate professor Chris Alford, had the same results when 20 drivers attempted a more varied, stop-start "commute to work" drive.
"They were clean to drive in terms of blowing a breathalyser, but actually they were really quite impaired," Prof Alford said.
"We found people's reactions slowed . . . It was a mixed bag of general driving control and making more errors, swinging from side to side and going over white lines.
"If you give your poor old brain a knock with the booze, it takes a while to get up to speed again. We're beginning to understand that, when it comes to our brains, alcohol and drugs have a lasting effect."
AA spokesman Dylan Thomsen said the findings emphasised the importance of driving responsibly.
Otago University of Wellington associate professor Nick Wilson said studies had shown that driving with a nasty flu was also comparable to driving under the influence.
- Fairfax Media