It’s the time of year, where perhaps more so than others, more alcohol
is consumed, at home, parties, and at lunchtimes. It is also a time when
more drivers are over the drinking limit. Drink driving devastates lives!
Without putting a damper on ‘spirits’ here is some information which
may help to prevent people from driving whilst over the limit.
What is the drink-driving limit in the UK? (For other countries you
can find this information on the internet by searching for drink drive
limits)
- 35 micrograms of alcohol in 100 millilitres of breath; or
- 80 milligrams of alcohol per 100 millilitres of blood; or
- 107 milligrams of alcohol per 100 millilitres of urine.
Guidelines on what over the limit means in terms of units of alcohol are
difficult judge and do not translate easily (or safely) into the units we
see on drink labels.
There are many factors to consider, including gender, body mass, if
someone is on medication and how quickly alcohol is absorbed into the
bloodstream. The reality is that to be sure that you will not be
driving over the limit; it is safer to not attempt to drive
after drinking ANY alcohol.
Alcohol affects the brain and body. It is a depressant; therefore it slows
the central nervous system down. It affects co-ordination, judgement
and reaction times.
Alcohol works through the brain from front to back. It affects the frontal
lobe first, which controls cognition, memory and reasoning, including
moral reasoning. This is why people start to lose their inhibitions, ability
to reason and therefore have a greater tendency to taking risks. This is
also why some people (wrongfully) think that alcohol is a stimulant and
may feel they are safe to drive. It can be difficult to persuade someone
that they aren’t safe to drive at this point. The effects can occur after
only 2-4 units of alcohol have been absorbed into the system. If a
person continues to drink beyond this point, other parts of the brain are
affected, and gradually the brain and body are slowed down.
Of course it isn’t just the same day or evening of drinking that can
lead us to being over the limit, but also the next day.
The liver can process approximately one unit of alcohol each hour. It
starts processing the alcohol around 20 minutes after the first drink is
taken, so if a person has drunk 10 units of alcohol, it will take
approximately 10 hours for the body to have removed the alcohol from
the system.
How do we calculate units of alcohol?
There are a number of ways in which units can be calculated.
One way is;
% abv (alcohol by volume) x millilitre content
1000
So for example, a 250ml glass of wine at 12.5% ABV contains 3.125
units of alcohol
1 unit is equal to:
- Half pint ordinary strength beer/cider (3.5% ABV)
- A 125ml glass of wine (9% ABV)
- A 25ml pub measure of spirits (40% ABV)
Points to consider:
- There are generally much stronger beers served in pubs,
restaurants and at parties;
- Few places serve a small 125ml glass of wine. Usually the
serving is 175ml for a small and 250ml for a large;
- Even when a 125ml glass is served, the average wine is
around 12-12.5 % ABV (Just 80ml of 12.5% ABV wine =
one unit);
- If you are at a restaurant or pub, you won’t always see the
number of units of alcohol of your drink or the percentage of
ABV;
- If you are at home or a party and drinks are poured and not
measured, you can’t know exactly how many units you are
drinking;
- Knowing how many units have been consumed relies on a
person remembering what and how much they drank, which
becomes more difficult as they consume more.
What about if you ‘feel sober’ enough to drive or operate
machinery?
- Even if you feel sober you may have far more alcohol in your
system than you realise. The more regularly you drink, the
higher your tolerance level to the feeling of being drunk is likely to be;
- Having a cold shower, fresh air or a cup of coffee to make you
feel more alert, does not alter the amount of alcohol in you. Only
time will do this and as has already been stated it takes
approximately one hour to process each unit of alcohol you have
had;
- You may still be over the limit a few hours after you have
finished drinking alcohol, which can make you over the limit later in
the day, if you had a drink at lunchtime, or the following day, if you
were drinking the evening before;
- Even if you are below the limit, co-ordination, driving, operating
machinery and decision making may still be erratic.
The importance of keeping ourselves and other people safe, and
the need for planning how to travel, if we plan to drink alcohol, is
very clear. Equally, if we know someone has been drinking
alcohol, we too have a responsibility to ensure they do not put
other people’s lives at risk.