How Long Does Alcohol Stay In Your System

How Long Does Alcohol Stay In Your System

Do you want to know how long alcohol stays in your system? Many people ask this question after having a few drinks because they don’t know when it’s safe to drive again. Or, depending on the type of employment, you may want to make sure that you don’t drink too much at night to stay under the alcohol limit the next morning.  So, knowing how long alcohol stays in your body can be a question of a great importance.

How Long Does Alcohol Stay in Your System?

Many people forget that alcohol can stay in your system long after its effects have worn off.

There is no way to speed up the way that your body gets rid of alcohol. So this means that having a cold shower, drinking strong coffee, or even sleeping for a few hours won’t affect how long alcohol is in your blood stream. Only time can reduce the level of alcohol in your system.

What affects how long alcohol stays in your system?

Alcohol gets absorbed into your bloodstream fairly quickly but is then metabolized much slower. The George Washington University1 says that the effects and levels of alcohol in the body depend on a number of factors, including:

  • Your size and weight
  • The type of alcohol consumed
  • Your metabolism rate
  • Food intake

However, once alcohol is in your system there is nothing you can do to speed up the rate at which your body gets rid of alcohol. In fact, depending on the amount of alcohol a person has consumed, alcohol could still be in their system for up to 18 hours after.2

Alcohol can be detected in your breath, sweat, blood, and urine. Usually, the police will carry out a breath test to check the blood alcohol concentration (BAC) to determine if a person is over the legal limit for driving. In other cases, doctors may perform urine or blood test to check the BAC.

How Blood Alcohol Concentration (BAC) Changes Over Time

Basically, the BAC is a measure of the ratio of alcohol in your blood.

For example, a BAC of 0.10% means that for every 1000 parts of blood you have 1 part alcohol.

Your body generally metabolizes alcohol at the rate of 0.015% per hour. You can use this information to calculate how long alcohol stays in your body.

For example, if your BAC level is 0.06:

  • After 1 hour your BAC will be 0.045
  • After 2 hours your BAC will be 0.03
  • After 3 hours your BAC will be 0.015
  • After 4 hours your BAC will be 0

As you can see, it take 4 hours for the body to metabolize all the alcohol. Once you know the current BAC level you can answer the question of how long it takes the alcohol to get out of your system.

There are two ways to find out your current BAC level:

  • The easiest way is to use a breathalyzer, a portable breath alcohol tester (like this one)
  • Or you can manually calculate it or use online BAC calculators.

There is a handy online calculator for finding your current blood alcohol concentration in the Cleveland Clinic website.

There is another calculator which also takes into consideration your gender and you can find it here.

I’ve tested the above two calculators and the results are not exactly the same but very close. The second BAC calculator takes into consideration a few extra parameters and this affects the final result.

In the next section I am going to show you how to manually calculate your BAC. Towards the end of the article I will share with your a few tips on how to delay alcohol absorption in your system.

How to Manually Calculate Blood Alcohol Concentration (BAC)

To calculate your current BAC you need to base this on the amount of alcohol in a standard drink. The National Institute on Alcohol Abuse and Alcoholism says that a standard drink contains 14 grams of pure alcohol.3 This is the equivalent of:

  • 12 fl. oz. regular beer with about 5% alcohol
  • 5 fl. oz. wine with about 12% alcohol
  • 5 fl. oz. spirits about 40% alcohol

The BAC also depends on your gender and weight and the time-frame the alcohol was consumed in.

Here is a handy formula to help you calculate alcohol concentration (AC) in the blood called the Widmark formula.4

Blood Alcohol Concentration in Body (BAC)
r = the whole body alcohol distribution ratio:

  • r = 0.55 for females
  • r = 0.68 for males

Example: A 120 pound female of average build consumed 6 drinks containing 1 ounce each of 40% alcohol from 10:00pm to 2:00 am.

What is the alcohol concentration (AC) at 3:00 am?

Time from start of drinking to 3:00 am = 5 hours

The following conversion factors are used:

  • 1 fl. oz. = 29.6 mL
  • 1 mL alcohol = 0.789 grams alcohol

Blood Alcohol In Your System

Can you speed up alcohol absorption in the body?

Unfortunately, there is no way to speed up the process that the body metabolizes alcohol. Once the amount of alcohol in your system reaches a certain level, all you can do is wait for the liver to do its job (remember though that excessive alcohol consumption is one of the 5 common habits that can damage your liver).

How Long Does Alcohol Stay in Your Urine?

The amount of time that alcohol stays in your urine depends on how much alcohol you have consumed. However, alcohol can still show up in your urine for up to 12 hours after you have stopped drinking.5 But an Ethyl Gluconoride test can detect alcohol in urine for 3-5 days.

How Long Does Alcohol Stay in Your Blood?

Again, this depends on how much alcohol you have consumed. You can use the BAC calculation to determine if it is likely that you still have alcohol in your body. Alcohol can be detected in your blood for up to 12 hours in a breath test.6

The breathalyzer test is actually a very accurate method to detect the amount of alcohol in your blood. A company that specializes in drug testing of people in the workplace says that the BAC level on the breath test will be exactly the same if your blood was tested for alcohol at the same time.7

So, it is important to remember that alcohol can stay in your system long after you have stopped feeling its effects. Therefore, if you have to drive or your workplace has a policy on BAC levels, you should think about how to lower alcohol levels in your blood.

How to Lower Alcohol Levels or Delay Alcohol Absorption?

The best way to make sure that alcohol stays in your system for as short a time as possible is to be responsible when drinking. How can you do that?

First of all, it is important to remember that alcohol is alcohol whatever form it comes in. Therefore a breathalyzer doesn’t distinguish if you have been drinking beer, spirits, or wine. Different combinations of drinks won’t affect how quickly alcohol leaves your body. Also, the body metabolizes alcohol at a standard rate and there is no way to speed up that process.

So, if you have to be at work or drive early the next day (or even later in the day depending on how much you drink) the only way to make sure that the alcohol is no longer in your system is to limit your drinking.

Therefore it is a good idea to sip your drinks so that one drink lasts you longer. Some people recommend only having one standard drink per hour.

Also, switch between alcoholic and non-alcoholic drinks. This means that your overall BAC levels will be much lower. Remember that the body can take at least an hour before it metabolizes one standard drink.

Because alcohol is rapidly absorbed once it reaches the small intestine, anything that delays the stomach from emptying its contents into the small intestine will slow the rate of alcohol absorption. Consuming alcohol with food will delay absorption and causes a lower peak alcohol concentration that lasts longer compared to consumption on an empty stomach.

Read these related articles:
1. 5 Common Habits That Damage Your Liver
2. Early Signs of Liver Damage & How to Strengthen Your Liver

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