How long does alcohol stay in your system? This is an important question for many who enjoy a few drinks but want to ensure they drink responsibly. Responsible drinking doesn’t just mean counting your units or staying within the recommended health guidelines, and it means considering the bigger picture and ensuring you are safe to carry out everyday activities such as driving the children to school or driving to work the following morning.
Drink driving isn’t always as simple as having one too many and getting behind the wheel of a car. You can still be under the influence or suffering from alcohol withdrawal effects well into the next day. This can make you a danger on the roads and generally less able to function capably, putting yourself and others at risk.
Here we look at how long alcohol stays in the human body, the effects of alcohol, factors that are variables in how long it takes alcohol to come out of your system, the dangers associated with carrying out day to day activities whilst under the influence of alcohol, the time frames in which various tests can detect alcohol in your system, safe drink driving limits for the UK and how to ensure you can be safe from alcohol’s effects before going about your day.
If you are a regular drinker and you also drive, you must be fully aware of the legal drink-drive limits for where you live. Drink driving limits can vary from country to country, so always check when you are travelling.
In England, Wales and Northern Ireland, the legal alcohol limit for drivers is 80 milligrammes of alcohol per 100 millilitres of blood, 35 micrograms per 100 millilitres of breath, or 107 milligrammes per 100 millilitres of urine.
The legal limit for drivers in Scotland has been different from the rest of the UK since 2014. The limit is 50 milligrammes of alcohol per 100 millilitres of blood, 22 micrograms of alcohol per 100 millilitres of breath, and 67 milligrammes per 100 millilitres of urine.
Breath testing is the most common form of roadside testing for drink driving in the UK. A positive breath specimen will usually be followed by a urine, saliva or blood test for accuracy.
Let’s make one thing absolutely clear – this information is not intended to help you work out how much you can drink on a night out before driving home.
In England, Wales and Northern Ireland the 80mg limit translates into four units of alcohol for a man of average height and weight. This is the equivalent of 2 pints of average strength beer (up to 5% alcohol content)
For a woman, this translates into 3 units of alcohol, which is the equivalent of 1 large glass of average strength wine (11 – 12%) or three halves of average strength beer.
Considering the number of alcoholic units involved, it is very likely that someone drinking this amount would feel its effects. Therefore, even though it is legal, this amount could still impair your ability to drive safely. If you are drinking on a night out – even one drink – you should leave the car at home and make alternative arrangements.
In reality, the safest amount of alcohol to consume before driving is none; especially if you have a low alcohol tolerance or are taking medication that could increase the effects.
Even if you are not drinking regularly or particularly to excess, alcohol is a toxin, and these toxins take time to be metabolised. Whilst the toxins are still in your body; you will experience alcohol’s effects. Alcohol affects both your mind and your body in a variety of ways; ways that make you more prone to accidents, poor decision making, risk-taking and even death.
You do not have to drink a lot to feel the effects. Naturally, the more you drink, the more severe the effects will be. Mild intoxication causes flushing of the skin, relaxation, confidence and euphoria.
The effects, especially when consumed to excess, can cause critical impairment to your judgement. It is this poor judgement and poor decision making that can land you, and indeed others, in a whole lot of trouble.
The human liver can metabolise around one unit of alcohol per hour. So, if you are drinking heavily the night before, chances are you will still have alcohol in your system the following day. Whilst you have alcohol in your system, you will still be under the influence of its effects.
As the alcohol works its way out of your system, releasing toxins, you can begin to feel unwell. These unpleasant comedown effects are commonly referred to as a “hangover”. A hangover can also severely impair your ability to function.
How much you drink also affects the rate at which the alcohol is metabolised. Binge drinking, which is defined as 8 or more units of alcohol for men and 6 or more units of alcohol for women, takes longer to pass through your system.
The human liver struggles to work as efficiently when it is overloaded. Therefore, if you have consumed more than the recommended safe drinking guidelines, you should not consider your liver to process the number of units at a standard rate of 1 per hour. It will take much longer for alcohol to leave your system after a drinking binge, as your liver works overtime, trying to rid your body of toxins.
Even if you are not abusing alcohol, typically it’s effects can be felt after more than one drink. For some individuals with a low tolerance, even one drink can affect the way they feel.
In addition to how much you drink and how frequently, several variables affect the rate at which you, as an individual can metabolise alcohol. These should also be considered when trying to weigh up if it’s safe for you to drive or undertake complex tasks the following day.
It’s important to remember that we are all different and react to alcohol differently. The same physical factors that make us unique as individuals also affect how quickly we can process it and other drugs.
The type of test that is used to detect alcohol in your system can also detect within different timeframes, so as you can see, it’s not as straightforward as simply counting units.
Aside from the short term effects that can be felt whilst alcohol is in your system, it also affects other things in your body that cannot be seen or felt.
Research conducted by the National Institute on Alcohol Abuse and Alcoholism found that alcohol impairs the function of your liver, heart, central nervous system, pancreas, brain and immune system. Whilst exposing your body to alcohol now and then will not cause any lasting damage (assuming you are not binge drinking), regular and heavy drinking can have a lasting impact on your vital organs ability to function.
Alcohol has also been linked to seven different types of cancer. The more you drink, the more at risk you are of developing one of these alcohol-related cancers (6)
Heavy and frequent drinking can also have a profound impact on your mental health. In fact, it can bring about the onset of several common mental health conditions and exacerbate pre-existing ones; depression and anxiety being the most common.
The metabolism is a somewhat complex process, involving many organs, bodily systems and chemicals. We have tried to simplify this into easily understandable terms.
When alcohol is ingested, it is first of all oxidised in the stomach into ethanol and passed into the small intestine where it is absorbed into the bloodstream. Naturally occurring chemicals and enzymes in the body then further break it down into partial ethanol and begin to metabolise it. The rest of the ethanol circulates in the bloodstream, reaching the brain and affecting it.
Once it reaches the liver through the bloodstream, two liver enzymes, alcohol dehydrogenase and aldehyde dehydrogenase, break down the separate alcohol molecules so that it can be eliminated from the body.
During the metabolic process, alcohol dehydrogenase helps to convert alcohol to acetaldehyde, an extremely toxic carcinogenic substance which is then broken down by further enzymes into acetate. The liver metabolises most of the alcohol in this way, but a small amount is eliminated from the body by forming into fatty acids. These particular fatty acids have been found to damage the liver, pancreas and brain tissue.
Finally, around ten per cent of the alcohol consumed is left unmetabolised and is instead eliminated from the body through urine and breath. This is how it’s presence can be detected – through drug testing and breathalysers.
Genetics can play a big part as to how long alcohol stays in your body—those who suffer from alcoholism process it at a slower rate than those who do not. The toxic, carcinogenic acetaldehyde remains in the system for longer, causing more damage, particularly to the brain and its tissues and pathways. This is believed to not only affect the individual physically but also contribute to psychological and behavioural problems commonly associated with addiction.
Genetics also determine which enzymes your body produces and carries and to an extent your metabolic rate, both of which affect how you metabolise alcohol.
Genetics is not the only factor that contributes towards misuse and alcoholism; environmental factors also contribute heavily. The point is, if you are an alcoholic and are abusing alcohol regularly, this will slow down the rate at which your liver can process alcohol.
Only about a tenth consumed can be detected in your breath and sweat, and the rest is metabolised within the body. Depending on the amount consumed and various factors that affect how long it takes and individual to process alcohol, ethanol can be detected in a breath specimen for up to 24 hours after the last drink was consumed.
The breathalyser is the preferred method of roadside testing used by police to detect drink driving, as it can be detected on the breath quickly and conveniently.
If you have had a heavy drinking session, we urge you NOT to drive at all the following day; this is to ensure that all the alcohol has left your system.
A breathalyser can provide accurate blood alcohol reading just 15 minutes after your last drink.
Alcohol urine tests are routinely used for tests by rehabs, local drug services, workplaces and the police.
It takes around 2 hours for consumed alcohol to filter through your system and kidneys and become detectable in your urine. This is why a breathalyser is usually the first test to be used.
Alcohol can be detected in urine for anything between 12 and 48 hours using a standard urine test. This is quite an ambiguous time frame, and the time it takes alcohol to leave your system through your urine is heavily influenced by the personal factors we have previously mentioned.
An EtG urine test, however, which examines (Ethyl Glucuronide) metabolites levels, can detect the presence of alcohol in urine for up to 3 to 5 days.
A blood test is the preferred method used by police for court evidence to prosecute for drink driving and will be used to back up a positive roadside breath specimen.
Alcohol leaves the bloodstream relatively quickly in comparison to urine but gives an accurate reflection of intoxication levels and blood alcohol concentration.
A blood test can detect ethanol in the blood for up to 12 hours. This, of course, is subject to personal factors that affect the individual’s ability to metabolise alcohol efficiently.
For an individual who drinks heavily or frequently, alcohol will be present in their bloodstream for longer.
Saliva, much like an alcohol breath test can detect alcohol in your system within a few minutes of consumption, and can detect it in your saliva for up to 24 hours after the last drink was consumed.
Saliva tests usually involve a swab sample of saliva being taken from inside of the person’s mouth and cheeks, until the swab is saturated with saliva for an accurate reading.
Alcohol Saliva tests are commonly used by rehabs and detox centres to ensure patients are not drinking and by community drug and alcohol services.
The concentration of alcohol present in the saliva is similar to the concentration of alcohol present in the blood. Saliva tests provide an accurate reading of intoxication levels.
An alcohol hair strand test can determine if a person has been using alcohol within the past 3 months, or 90 days. Similarly, hair strand tests can detect the presence of any drugs used within the past 3 months.
Hair strand tests do not confirm when a person has consumed alcohol and so are not used for establishing a current drinking episode. Hair strand tests tend to be used by legal officials or employers to test individuals who have a history of DUIs (driving under the influence).
If you have recently drunk alcohol and are considering ways to speed up the time it takes alcohol to leave your system, the reality is that any measures taken will have little impact on an alcohol test result.
It is a myth that caffeine/coffee sobers you up, it may make you feel more awake but does nothing to reduce your blood alcohol concentration (BAC).
If you want to reduce the effects of alcohol when drinking, it is recommended that you eat before drinking and stay hydrated. To reduce the effects of a hangover hydration is key. Make sure you drink plenty of water little and often and if you can eat some healthy food. Over the counter pharmacy, hangover remedies can also be helpful. Speak to your local pharmacist for recommendations.
Depending on the situation, your BAC and your past history can all affect how hefty a penalty your receive for a positive alcohol test and any additional consequences.
An alcohol test conducted by an employer could mean a disciplinary hearing resulting in a warning, probationary period or dismissal.
An alcohol test conducted by a court official or probation officer could result in a breach of probation/terms of release and subsequently, a return to court.
An alcohol test conducted by a police officer, depending on the circumstances of the test, will usually carry a penalty determined by a magistrate or judge at court.
Each case of drink driving is judged independently by the magistrates who hear your case and will depend on the nature of the offence.
Some magistrates will allow you to reduce a driving ban by attending a drink-driving rehabilitation scheme (DDRS) if you are banned from driving for a period of 12 months or more. This will be at the magistrate’s discretion and is not an automatic entitlement.
According to the UK government, the current penalties for drink driving are:
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Being caught and prosecuted for drink driving also carries other consequences. It can affect your job (if for example you drive for a living or need to drive to and from work). It can affect your relationships with a loved one, family and friends. The cost of your car insurance will increase and may become unaffordable. It is likely it will affect your self-esteem and cause you to suffer a lot of stress whilst going through the court process also.
Considering the penalties, the possible consequences and the repercussions of drunk driving, is it really worth risking driving after even just a few drinks?
If you or a loved one needs help with a drinking problem, you can access free support and help in the community through your GP and local drug and alcohol services.
Rehab Guide specialises in helping those that are alcohol dependent and where alcohol is costing them more than just money. Our private rehabs are CQC registered and offer the latest in affordable, effective alcohol treatment; including a full medical detox and bespoke rehabilitation programme.
Call us in confidence on 02072052845 to find out more.
Sources and references:
Gov.uk. The drink-drive limit. [Online]. Available at: https://www.gov.uk/drink-drive-limit. [Accessed 20 November 2019].
Mark Keller, George E. Vaillant. (2018). Alcohol consumption. Encyclopedia Britannica.
National Institute on Alcohol Abuse and Alcoholism https://www.niaaa.nih.gov/alcohols-effects-body
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