"Shock drink drive survey"

[supraman2954]

Following on from a recent thread relating to drink driving, I asked the question 'how long it takes to clear out the system after a heavy session'.

I found my answer on Sky news, but it seems to me to be somewhat extreme....

www.sky.com/skynews/article/0,,30000-13249218,00.html

Sky news article said:

SHOCK DRINK-DRIVE SURVEY As many as one in three motorists drive the morning after a heavy drinking session, a survey has revealed. The worst morning-after culprits are young drivers, with half admitting to getting behind the wheel despite probably being over the legal limit from the previous night's excesses. Many young drivers are uncertain about the time needed to be sober enough to drive, the survey from insurance company Direct Line found. Based on replies from 2,000 adults, the survey showed that males think it will take seven hours to be completely safe to drive and younger drivers (18 to 29 year olds) believe they can drive after six hours. However, medical research shows that it can take around 12 hours to be sober enough to drive after drinking four pints of continental lager or beer. This means after four drinks during an evening, many motorists will be over the drink-drive limit until late the following morning. Over half of all male drivers admitted to driving in the last year within two hours of having a drink. Direct Line spokeswoman Emma Holyer said: "The research shows the awareness among motorists is shockingly low towards the dangers of driving the morning after."

Does anyone have any real data regarding this, or should I now stick with the 3 pint rule?

[kevinday]

I do not drink and drive but have always worked on the basis of 6 hours from first drink, plus 1 hour per unit. Alcohol takes up to 6 hours to be absorbed into the body therefore the decay does not start until then. Four pints of lager = 8 units? therefore 14 hours before completely sober.

[pbirkett]

That sounds like BS to me.

4 pints = 10 units, and starting from the beginning of the first drink that is no more than 10 hours to be completely free of any alcohol. Also, I believe it was "bryan35" who stated that the first two pints are more or less free because the body cannot absorb them straight away so you can drink 3 pints in 2 hours and still be safe, or 4 pints in 4 hours (working on the assumption that you are safe after 2 pints, and adding 2 hours from the beginning of the first drink for every subsequent pint).

Quite honestly, 4 pints barely affects some people at all anyway.

[havoc]

OK, from my research on the web some years ago into this, the following seems to be the most consistent advice:-

The average human body metabolises (i.e. neutralises) about 1 unit of alcohol per hour.
1 unit of alcohol is:-
- 1 25ml shot
- 1/2 pint of weak lager/bitter (i.e. ~3.5%ABV)
- about 75ml of wine
So a pint of Stella is 3 units; a bottle of wine contains 10 units; etc.

The human body DOES start absorbing alcohol straight away - how would you get drunk otherwise? And as a consequence it starts metabolising it soon after. I am not aware of ANY 2-hour gap.

So, if you have 4 pints of Stella, that is 12 units. You will not be safe to drive until AT LEAST 10 hours after you started drinking (12 less the 2-unit drink-drive limit, if you want to chance it).

Note above I said "average person" - everyone is different, and, unlike alcohol tolerance, this one is not necessarily affected by body-mass, so you rugby players can't assume you'll be OK quicker...and as you can typically drink more, be careful!!!

[bryan35]

Your body does begin absorbing straight away, but it can't absork the lot all at once, and stomach contents slow the process down. 1 unit will typically put your blood alcohol level up such that your breath sample will increase by 7.5mg/ml of breath.
the legal limit is 35mg/ml.
Your body neutralises about 7.5mg.ml an hour.

work it out from that.

[piccy mate]

If I remember rightly, The RAF had a '12 hours twixt Bottle & Throttle' ruling to ensure drivers/pilots had a clear head!
Piccy

[supraman2954]

havoc said:

……… less the 2-unit drink-drive limit……..

Havoc, are you sure that is correct? This would mean that 1 quick Stella would put you 50% over.



There seems to be a consensus that it takes 1 hour to neutralise 1 unit.

So 4 Stellas would be 12 units, minus 4.6 units for the drink drive limit (4.6 x 7.5 = 35mg/ml) leaves you with a minimum of 7.4 hours (from the 1st pint) before the average person becomes legal.
1st pint at 8pm results with the average person becoming legal at 3:30am.
Interpreting this in a different way, 50% of these people would still be over the limit at this time.

I wonder what percentage of people would still be illegal after 12 hours, can’t be many (I hope).

[bryan35]

havoc said:

So, if you have 4 pints of Stella, that is 12 units. You will not be safe to drive until AT LEAST 10 hours after you started drinking (12 less the 2-unit drink-drive limit, if you want to chance it).

12 units (absorbed instantly) would push your breath alcohol level up to 90mg/ml which is 55mg/ml over the limit.

This will drop by 7.5mg/ml per hour, so you'd reach 35mg/ml in about 7.5 hours.

[sandman]

doesn't it all depend on an individuals metabolic rate ....?? If so that will depend things like on how much you've eaten before during and after the drinking session, and how much exersize you've done before during and after the drinking session. Plus have a good 8 hours sleep after having a few ales will be different than having a few drinks and staying awake for 7/8 hrs. The bottom line is - its going to be different for everyone. These "guide" figures are about as much use as the body mass index figures they use at the doctors - a complete waste of time - because it depends on the individual.

[havoc]

I would question that 4.6unit drink/drive limit. When they reduced it, the press was talking about how it had gone down from two pints to one pint (talking about standard, 3.8%ABV stuff, i.e. 2 units!)

I might well be wrong, but in my opinion it's never a good idea to gamble with stuff like that.

So regardless, we're at a consensus of 3units/pint, and 1hour/unit metabolising. So ideally don't have any more than 4 stellas if you've got to drive to work the next morning.

[Mr Whippy]

I think, the 1 unit per hour is a good indicator. I think the best saving grace of big rugby player types is that they have more blood, and their metabolism is faster all the time to sustain their higher muscle mass.

All kinda speculation, but the way I look at it is, I'm 15 stone, and quite well built, and I get pissed on four Stella's these days. I don't drink often, and so have become a "light weight".
It takes me days to recover after 6 pints of Stella

However, in my skinny student days, 12 pints would go down alot easier, and I'd feel fit as a fiddle the next day, and sobering up in the taxi home!

Best to be sensible. I've never felt drunk the day after, though I can feel tired and dried out! Suppose the law is the law, and a number is the law these days. If your blood "says" your over, thats it.
However, I wonder if the blood alcohol level effects you in a "hangover" the same as it does when you are getting drunk and being drunk!

Dave

[hiasakite]

This depends loads on a persons body mass and metabolic rate... and the metabolic rate varies depending what they are doing... eg sleeping it off allows the alcohol to linger around much much longer than doing a workout...

Buy a breathaliser, find out for yourself how much it effects you and be safe of the limit..