3 Reasons Why You Black Out From Alcohol

What Is Alcohol Blackout?

An alcohol blackout generally refers to the memory loss that occurs after drinking too much alcohol at one time. This is sometimes also called “alcohol-induced amnesia” or an “alcohol-induced blackout.” Blackouts can refer to both complete or partial memory loss with the latter sometimes also called a “gray out.” Frequent blackouts are a common sign of alcohol abuse and misuse.

As your blood alcohol levels rise, your brain is unable to form new memories, even though you’re still awake and interacting with your environment. The higher a person’s blood alcohol concentration (BAC), the more memory loss they are likely to experience.

Alcohol blackouts don’t typically affect the memories you stored before the blackout occurred. Instead, you will remember everything clearly up to a certain point, at which your memories become fuzzy and eventually disappear altogether. As someone “sobers up” or their blood alcohol concentration level starts to decrease, they will begin to form memories once more.

Keep in mind that blacking out and passing out from drinking are not the same thing. During an alcohol blackout, you’re still able to talk, make decisions, and continue drinking. When you’re passed out from alcohol, you will be unconscious and won’t respond to stimuli including people nudging you or speaking to you.

Because everyone is unique, people who are blacked out from drinking may appear to be functioning mostly normally or be so intoxicated that they have trouble walking or standing. Because people aren’t in full control of their bodies at this point, they are much more likely to engage in risky behaviors such as drunk driving or unprotected sex as well.

What Causes Blackouts?

Although drinking too much may be what most people think of when they hear the term “blackout,” blackouts can refer to any partial memory loss or unconsciousness like fainting.

Some potential reasons for blacking out include:

  • Drinking too much
  • Brain damage
  • Taking certain medications or drugs
  • Witnessing or experiencing a traumatic event
  • Epilepsy
  • Low blood sugar
  • Lack of oxygen
  • Abnormalities of the heart or heartrate
  • Stress or anxiety

What Causes Alcohol Blackout?

What causes someone to blackout from alcohol specifically lies in the brain’s inability to function normally and efficiently while someone is under the influence. When you are sober, you form memories by receiving sensory input, processing it, and storing it in your short-term memory. Next, the experience is transferred into long-term memory in the hippocampus by a process known as encoding so that people can recall these memories later.

When you drink too much alcohol, the brain is not as efficient, and all of these memory processes become impaired. Specifically, heavy drinking is believed to interfere the most with the encoding stage.1

As a result, when someone’s blood alcohol level reaches a certain amount, they lose their ability to form and retrieve new memories. For most people, an alcohol blackout starts at around a blood alcohol concentration level of 0.14, but the onset of an alcohol blackout varies from person to person.

Why Do I Black Out When I Drink Alcohol?

Some people are more likely to blackout after drinking than others. While some of this is tied to individual differences, drinking habits can be a big contributing factor as well.

You are more likely to blackout from alcohol if you…

  1. Binge Drink

One of the biggest causes of a blackout from drinking is consuming too much too fast. When you drink alcohol rapidly, your liver cannot keep up and metabolize the alcohol fast enough. This causes blood alcohol concentration levels to rise quickly until you reach the point of an alcohol blackout.

  1. Drink on an Empty Stomach

If you drink on an empty stomach, it won’t take as much alcohol to raise your blood alcohol level as it would if you had been eating. Drinking alcohol without food gets you intoxicated much faster and increases your risk of blacking out.

  1. Have A Low Tolerance

Although most people won’t blackout until they reach a blood alcohol concentration level of 0.14, some people may blackout sooner. If you are more sensitive to alcohol than the average person, it may not take as much to cause you to experience an alcohol blackout.

  1. Have A Higher Body Mass Index

Body mass index (BMI) refers to the amount of body fat someone has based on their height and weight. A large amount of blood flows through muscle tissue, but much less blood flows through fat. People with a higher BMI have a higher concentration of fat and therefore, a lower volume of blood. As a result, the alcohol in the blood is more concentrated in people with less muscle leading to a higher BAC faster.2

  1. Are a Women

Some studies suggest that women are more likely to experience an alcohol blackout than men even when they drink less.3 This gender discrepancy may be tied to differences in body size, composition, and chemical makeup.2


If you’re experiencing alcohol blackouts on a regular basis or know someone who drinks in excess, it may be a sign of an unhealthy relationship with alcohol. At Vertava Health MS, formerly Turning Point Treatment, we are here for you.

Although alcohol is legal for those over 21, its frequent and heavy use is dangerous. Even if you or a loved one is not drinking to the point of blackout, it doesn’t mean that there isn’t a problem. Our rehab for alcoholic rehab facilities in Mississippi helps people quit drinking for good. Contact us today to learn more.

Call Vertava Health now!