Why Do I Black Out When I Drink Alcohol?

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Blackouts can be a frightening experience. They are a common side effect of excessive drinking—especially binge drinking. If you or anyone close to you has experienced one or more blackouts, you may have a pretty good idea about how they happen. 

However, for your health and safety around alcohol it is essential to dig deeper into the subject: Why do they occur? What is the science behind blackouts, who is more likely to get them, and how can you stop them from happening?

This article will address all of this and more, starting with an “alcohol blackout” definition. So, let’s forge ahead!

What Does Blacking Out Mean? 

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Photo by Dan-Cristian Pădureț on Unsplash

To begin with, what is a blackout? 

A “blackout” is a period of time when, although awake and doing things, you recall nothing due to the effects of alcohol. While this commonly occurs among people addicted to alcohol, it can happen to anyone who drinks a large amount in a short period of time. We frequently hear college students talk about that time they “blacked out.”

Here is an illustration of what occurs: You might remember meeting some friends for a few drinks. The rounds are circulating rapid-fire, and before you know it you are feeling no pain…

And that’s it. Rest of story deleted. Just blank space until you wake up feeling sick the next morning.

You may possibly remember some snippets, or hear stories from your friends, but you generally have no recollection of what happened while you were drunk. You then get struck with an awful, sinking feeling, wondering, “What happened? Did I say or do anything regrettable?” 

Partial vs Total Blackouts

There are two forms of alcohol blackouts. Some people forget everything from the night before, while some remember a few bits and pieces.

The first type is referred to as a “total” or “complete” blackout. As implied, it involves total memory loss during inebriation, which can’t be restored under any circumstance.  

The second type is what is known as a “partial” or “fragmentary” blackout, also referred to as “gray out.” Partial blackouts are more common. With this type, you may not immediately remember things that happened while you were drunk, but certain cues can trigger some memories to be restored. This might also mean having a spotty memory, with some sections missing.1

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Why Do I Black Out When I Drink?

People generally black out because of the amount of alcohol they consume and the speed at which they consume it. 

According to the National Institute on Alcohol Abuse and Alcoholism, “blackouts are more likely to occur when alcohol enters the bloodstream quickly, causing the blood alcohol content (BAC) to rise rapidly.”2 This can happen if you drink on an empty stomach, or binge drink (typically defined as at least 4 drinks for women or at least 5 for men over a 2-hour period). Women may be at higher risk for blacking out than men, as they typically weigh less.

How Alcohol Affects Your Brain and Memory

Alcohol is a known central nervous system (CNS) depressant, meaning that it reduces the activity of your neurons (also referred to as your brain cells).3 Understandably, this effect increases as you consume higher quantities of alcohol. Continued drinking can lead to “blacking out”—or a loss of memory past this point. 

Blacking out occurs when you have enough booze in your system to inhibit your hippocampus—the part of your brain that creates and stores memories.4 With this area disabled, you may not record anything that happens. You will be unable to recall the events of the night before, as if they were simply erased.

According to an article in Alcohol Research and Health, “As the amount of alcohol consumed increases, so does the magnitude of the memory impairments. Large amounts of alcohol, particularly if consumed rapidly, can produce partial (i.e., fragmentary) or complete (i.e., en bloc) blackouts, which are periods of memory loss for events that transpired while a person was drinking.”5

How Long Do Blackouts Last?

The length of an alcohol blackout varies from person to person, and can last from hours to days.6 Typically a blackout will end when your body absorbs the alcohol and your brain can again make memories. 

Factors that affect the duration are the amount you drink over a period of time, the type of alcohol, and your physiology. Sleep can help, because resting gives the body time to process the alcohol. 

Who Is at Higher Risk For Blacking Out?

There are certain groups considered to be more susceptible to blackouts. According to the Journal of American College Health, college students fall into this category, given the social atmosphere.7 Those who struggle with alcohol use disorder are thought to be another high-risk group. 

As stated above, women may be at higher risk for blackouts than men because they typically weigh less and have less water in their bodies (thus reaching high BAC levels more quickly). Finally, those who take sedatives such as Oxycontin or Xanax are also more likely to experience blackouts.8 

However, it’s likely that blackouts are more common among social drinkers than is often assumed. They are a potential consequence of heavy drinking, no matter who you are.9

Does Blacking Out Make You an “Alcoholic?

man walking through tunnel, how to stop blacking out when drinking
Photo by MARK ADRIANE on Unsplash

The answer here is “yes and no.” It is a common warning sign, and drinking to the point of blacking out can be a symptom of at least mild alcohol use disorder

But this isn’t always the same as being an “alcoholic.” For example, perhaps you are not normally a big drinker, but you overindulged at a wedding or bachelor party, resulting in a blackout. You then returned to your typically sober lifestyle once the celebration was over. For you, it was likely an isolated situation, and you are probably not an “alcoholic.” (Although drinking to this level is still dangerous, and best avoided in the future.) 

However, having an alcohol use disorder can certainly increase your risk of having blackouts, given the quantity and frequency of your drinking. 

Consequences of Blacking Out

As you can imagine, blacking out can have many undesirable consequences—from physical or social, to dangerous and even fatal. Let’s take a closer look at some of them. 

Dangerous Behavior

During the blackout stage, you are still conscious and able to move around. That, combined with being drunk and of impaired judgment, can lead to some very poor choices. 

One study indicated that college students who had blacked out “later learned that, during the blackout, they had vandalized property, driven an automobile, had sexual intercourse, or engaged in other risky behaviors.”10 

Less dangerous, but still harmful, are hurtful words and actions that you may inflict on friends and loved ones. Alcohol abuse has long been the reason behind many damaged relationships. 

Consequences For Your Body

Being intoxicated enough to experience a blackout means there is a lot of alcohol in your system, and heavy drinking can lead to many health issues, including:

How To Stop Blacking Out When Drinking

Since blackouts are associated with heavy intoxication, your best bet in avoiding them is to limit your consumption. It is especially important to avoid drinking if you are taking certain depressants, such as Valium or Ambien, as blackouts are more likely to occur when these substances are combined with alcohol. 

Here are some steps you can take to limit your consumption, and slow the effects of alcohol: 

  • Space out your drinks, or alternate them with water
  • Eat a full meal prior to drinking alcohol
  • Stay hydrated
  • Set a drink limit before you begin, and ask a friend to help you stay on track
  • Discover enjoyable “sober” activities—like movies, hiking, cooking classes, etc.

If you need additional support to control your drinking in social situations, or you frequently experience blackouts, help is readily available. Online programs like Ria Health can help you cut back or stop drinking, all from the comfort and convenience of home. We offer access to weekly coaching meetings, anti-craving medications, digital support groups, and more—right from your smartphone.

Get in touch with a member of our team today, or learn more about how it works.


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Written By:
Lisa Keeley
Lisa Keeley is a freelance writer who believes in the uplifting power of words. She especially enjoys writing about health, relationships, employment, and living one’s best life. Lisa has a Master’s in Education and previously worked in vocational and educational services. Her articles can be found on Your Tango, Thrive Global, Heart to Heart, Medium, Muck Rack, and on various professional websites.
Reviewed By:
Evan O'Donnell
Evan O’Donnell is an NYC-based content strategist with four years’ experience writing and editing in the recovery space. He has conducted research in sound, cognition, and community building, has a background in independent music marketing, and continues to work as a composer. Evan is a deep believer in fact-based, empathic communication—within business, arts, academia, or any space where words drive action or change lives.

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