Study shows we don't know when we've had too much to drink

Researchers asked drinkers how drunk they felt on a scale of 1 to 10 before testing how drunk they actually were. Photo / Getty Images

Drunk people have no idea how wasted they are — and Aussie scientists reckon they have the data to prove it.

An intrepid team of researchers at Deakin, La Trobe and Curtin universities hit up bars and pubs across Australia to compare how drunk people thought they were versus how drunk they actually were, reports news.com.au.

Armed with a breath tester they asked: "On a scale of zero to 10, how drunk are you?"

Peter Miller, a Professor of Violence Prevention and Addiction Studies at Deakin University told news.com.au the results show our ability to determine our level of intoxication gets worse the more we drink.

"Basically there's no point sitting there obsessing about whether you've had too much to drink — because research shows we're just not very good at it.

"A big factor in this is the fact that it can take up to an hour for our bodies to process alcohol.

"So if you've just had five drinks pretty quickly — you might say you're feeling OK and carry on drinking. By the time your body has processed this alcohol you might be feeling very different."

He and his fellow researchers found when people reached about twice the legal blood alcohol limit they could longer tell how drunk they were.

Deakin University drug and alcohol researcher Dr Nic Droste said judging the point at which someone is too intoxicated to be served or permitted entry is a difficult task.

The report shows that physical signs of drunkenness, such as red or glazed eyes, slurred speech patterns and impaired walking or staggering, appear at different stages for different people. It all depends on "individual and environmental factors".

"Even professionals who are experienced with alcohol — such as police, doctors, nurses, bartenders, psychologists, and alcohol counsellors, often make inaccurate assessments," the report states.

"Studies have found that a significant number of intoxicated drinkers escape detection, for example if they are frequent heavier drinkers who may have developed a tolerance to alcohol."

Dr Droste said the new research shows that the responsible service and consumption of alcohol becomes increasingly dependent upon the venues and staff that provide the alcohol.

"In a busy environment it can be difficult to isolate those who are just a bit tipsy and having a good time from those who are just far too drunk," Dr Droste told AAP.

"We were really surprised that no-one had measured intoxication levels in night-life districts before."

The team spoke to more than 7000 people across Sydney, Melbourne, Perth, Wollongong and Geelong, some designated drivers and others so drunk "we stopped the interview and made sure they were OK".

"A lot of people were just interested to talk to someone," Dr Droste said. "It doesn't sound very romantic, to talk to an interviewer, but some lonely people out there just wanted to chat." He said the research highlights the importance of responsible alcohol service.

People who are generally too drunk to keep drinking stagger or fall over, slur their words or become incredibly boisterous or confused, Dr Droste told AAP.

"(Venues) have got a responsibility to their patron."