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Alcohol affects your thinking, behavior, and ability to function. A person who drinks more and more will eventually tolerate its effects.
Alcohol tolerance develops over time. It is when the same amount of alcohol can no longer produce the same effects. This requires you to increase your alcohol intake to feel the original effects.
It's often caused by heavy and long-term alcohol use.
As a result, chronic drinkers who develop a tolerance need to drink more to get the same effects they used to have with less alcohol.
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If you drink heavily for too long, the body adjusts to the increasing presence of alcohol. This is known as alcohol tolerance.
Alcohol tolerance can be classified as metabolic or functional.1
When you drink alcohol, it is broken down into a simpler compound called ethanol. This makes it easier for the body to metabolize and eliminate.
The liver can only metabolize a certain amount of alcohol every hour.2 However, some people can do it more efficiently than others.
Metabolic tolerance is the enhanced ability to process alcohol. It is caused by a group of liver enzymes that get activated with chronic drinking.
These liver enzymes break down alcohol faster, reducing the time it stays active. In turn, it lessens the impact of alcohol on your body.
People who have functional tolerance are less responsive to alcohol's effects. It's the brain's way of adapting to chronic alcohol consumption.
Functional tolerance can reduce alcohol-induced impairment. A person's behavior and function are not significantly affected by their drinking.
Drinkers with functional tolerance will show few obvious signs of intoxication despite high blood alcohol levels.
Functional tolerance is mainly caused by excessive drinking. But other factors lead to its development.
Below are the different types of functional tolerance:
Most people develop tolerance after repeated exposure to alcohol. This usually happens over several drinking sessions.
Alcohol tolerance that occurs in a single drinking session is called acute tolerance. A person who has it will show decreasing alcohol impairment.
If you have acute tolerance, you appear more intoxicated when you start drinking. Later during the drinking session, you will exhibit fewer signs of intoxication despite having the same BAC as when you started drinking.
When you repeatedly perform a task under the influence of alcohol, you learn to do it more efficiently while intoxicated.
This is known as a learned tolerance to alcohol. It allows you to function almost at the same level as someone who has not been drinking.
Learned tolerance (also called behaviorally augmented tolerance) is a classic sign of functional alcoholism. However, not all people with a learned tolerance are high-functioning alcoholics.
Regularly drinking in the same place may cause you to develop tolerance.
When you have environment-dependent tolerance, you can better tolerate alcohol if you drink in the same environment or somewhere similar.
But if you drink in a new place, you will lose your tolerance.
This type of alcohol tolerance is common in social drinkers who tend to drink in the same social settings.3
Drinking every day can lead to tolerance regardless of environmental influences.
When place isn't a factor, it's called environment-independent tolerance or consumption-induced tolerance.
It usually occurs in people with alcohol use disorders (AUDs) such as alcohol abuse and alcoholism.
A person typically shows signs of intoxication when they reach specific blood alcohol concentrations (BAC).
Low alcohol tolerance means you show these signs at lower drinking levels than usual.
High alcohol tolerance suggests that you can consume more alcoholic beverages and not seem drunk.
A person's tolerance can change over time. A variety of factors play a role in alcohol tolerance. Your drinking behavior and environment can increase or decrease your tolerance.
Other factors that affect alcohol tolerance include:
The liver produces two enzymes for alcohol metabolism: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).
Researchers discovered that people carry different variants of these enzymes, affecting their metabolic tolerance to alcohol.2
For instance, many people of Chinese, Korean, and Japanese descent have ADH1B*2. The enzyme helps with a more rapid elimination of alcohol, decreasing their risk for alcoholism.
African-Americans have ALDH1A1*2 and ALDH1A1*3. These enzymes are linked to lower tolerance and an increased risk for alcohol use disorder.
Having a high tolerance makes you less prone to alcohol's impairing effects.
You might think it is a benefit of drinking. But a high alcohol tolerance increases your risk for other problems.
Tolerance often leads to increased alcohol consumption. Since you are not easily affected by alcohol, you will likely drink more than usual. On the other hand, metabolic tolerance can lead to serious liver damage.
Over time, this can lead to a physical dependence on alcohol. Alcohol dependence changes the way your brain functions.
When alcohol-dependent people cut back on their intake, they experience intense cravings and withdrawal symptoms.
Most people would rather continue drinking than deal with alcohol withdrawal. Unfortunately, this forces you into a cycle of alcohol abuse. Both functional and metabolic tolerance cause serious effects.
Unless you stop drinking, you might develop:
Meanwhile, people with high tolerance are more resistant to alcohol's effects. They are more prone to alcohol use disorders (AUDs). It takes more alcohol and a longer time before an alcohol use disorder develops.
Ultimately, it depends on how much alcohol you consume and how frequently you drink. You can have a high alcohol tolerance and still develop alcoholism if you drink heavily for prolonged periods.
Studies show that a higher alcohol tolerance predisposes you to increased alcohol consumption and alcoholism.6
In some cases, tolerance may already be a sign of alcohol use disorder. It suggests an unhealthy drinking behavior, causing you to develop tolerance.
A health professional can assess you for signs of alcoholism. They can provide treatment options and help you with the next steps.
Alcohol tolerance can be reversible. Abstaining and reducing your alcohol intake can lower it again.
If you developed tolerance but have not yet developed an alcohol use disorder, these tips could reduce it:
If you have signs of alcoholism or withdrawal symptoms that appear within hours of stopping or reducing your intake, you may need alcoholism treatment.
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