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What is Blacking Out?


Author: Thomas Roth

Last Updated: 2/07/2022

Blacking out occurs when the brain can no longer form new, short-term or long-term memories. When someone blacks out they forget things that were said to them moments ago and when the blackout subsides there is a good chance they won’t remember anything from the blackout period. Blacking out can be caused by consuming too much alcohol in a short period of time.

What are the Dangers of Blacking Out?

Blacking out is dangerous because people lose control of themselves and their bodies. Being blackout puts people at risk of falling and hurting themselves, harming others, engaging in unprotected sex, and even checking on vomit. The latter is especially bad because choking on vomit can lead to death if the throat can’t be cleared. When someone is blackout drunk and unresponsive, make sure you place them on their side.

What are the Types of Blackouts?

There are two types of blackouts. The types of blackouts are partial and complete and each type has different factors that contribute to the outcome of blacking out.

Blacking out can be caused by:

  • Epileptic seizures
  • Fainting
  • Low blood pressure
  • Medications
  • Oxygen restriction
  • Alcohol consumption
  • Psychogenic seizures

Still, alcohol-induced blackouts consist of fragmentary blackouts and en-bloc blackouts.

Fragmentary Blackout

A fragmentary blackout occurs when someone’s memory is shakey. These types of blackouts are commonly known as browning out. If someone had a night out of drinking they might remember some parts of the night and forget others. Events that occur during a fragmentary blackout can often be remembered if the individual is reminded of the events that transpired.

En-Bloc Blackout

En-bloc blackouts occur when BAC levels are too high in the body to form new memories. People who suffer from an en-bloc blackout won’t remember anything that occurs during this period and won’t form new memories until their BAC has lowered. Compared to fragmentary blackouts, en bloc blackouts tend to be more dangerous.

Who is Most At-Risk of Blacking Out?

Everyone is at-risk of blacking out because younger people tend to struggle with blacking out more than older drinkers. Young adults and teenagers are the most at-risk because these groups are more likely to binge drink and have a lower tolerance to alcohol. The combination of low tolerance and rapid drinking puts these groups at-risk of experiencing fragmentary and en-bloc blackouts.

What Causes a Blackout?

Alcohol-induced blackouts happen when someone’s BAC levels rapidly increase. The liver doesn’t have enough time to process the alcohol and the brain gets impaired. Binge drinking is one of the most common causes of blacking out because it consists of the rapid consumption of alcohol in a short period. Blacking out can also be influenced by low alcohol tolerance and not eating before drinking.

What Happens to Your Brain When You Blackout?

When someone blacks out from drinking alcohol the hippocampus region of the brain (the area responsible for memory) temporarily loses the ability to store memories. Neurotransmitters responsible for connecting memories between the prefrontal lobe and hippocampus become impaired and can no longer carry out their usual functions.

While blacking out causes memory loss the person can appear fine. Because the hippocampus still has long-term memory function, people can engage in conversations with peers and carry on for the rest of the night in most cases. Sadly, some alcohol and brain issues are fatal.

What Happens to Your Body When You Blackout?

Blacking out also has adverse effects on the body. Fine motor functions become impaired and it’s harder to walk in a straight line. Blacking out can also lead to vomiting, changes in blood pressure, breathing, and body temperature can also occur. People who suffer from blackouts can even experience bouts of hypothermia endured by rapid dehydration.

Blacking out also leads to issues after the body clears the alcohol. The next day people can experience headaches, diarrhea, stomach discomfort, vomiting, and more. When it comes to the body, alcohol effects vary based on how much is consumed.

What Complications do Blacking Out Lead to?

Blacking out can cause complications that range from mild headaches to death. There are several factors that determine the outcome of a blackout and most factors depend on how much alcohol you consumed. The more alcohol you consume the higher the risk of severe side effects.

Some of the most common complications of blacking out include:

  • Injuries from falling
  • Memory loss
  • Vomiting
  • Choking on vomit (occurs during sleep)
  • Headaches
  • Dehydration
  • Hypothermia
  • Changes in blood pressure
  • Changes in breathing patterns (slowed breathing or rapid breathing)
  • Diarrhea
  • Stomach discomfort

Depending on the person, someone who blacks out can experience none or all of these symptoms.

Are Some People More Prone to Blackouts?

Yes, blackouts are more likely to occur in people with lower body weights and among people who binge drink. Low body weight is a contributor because it decreases the amount of alcohol you need to raise BAC.

People who binge drink, particularly people of college-age and younger, also tend to blackout more than adults. Binge drinking is a factor because people rapidly increase their BAC and people within this age group have a lower alcohol tolerance.

How to Prevent Blackouts

Blacking out is preventable as long as you take the necessary measures to keep your BAC levels low.

Below we have a few of the best methods to prevent blackouts:

  • Eat a meal rich in complex carbohydrates and fats
  • Don’t engage in binge drinking (5 drinks in 2 hours for men, 4 drinks in 2 hours for women)
  • Stay hydrated
  • Sip on your drink instead of chugging it

These are a handful of ways to prevent blacking out but the best way to avoid it is to not drink at all. If you must drink, always make sure you drink responsibly.

Is Blacking Out a Sign of Alcohol Use Disorder?

Yes, blacking out can be a sign of alcohol use disorder. Alcohol use disorder (AUD) is the term used for alcohol addiction. People who suffer from AUD have uncontrollable urges to drink or need alcohol to have a good time. AUD can cause long-term health effects like high blood pressure, increased risk of stroke, and even certain types of cancer. Some people can even lose relationships and lose control of their lives when suffering from AUD.

There are several signs of alcoholism but frequent binge drinking and blacking out can be linked to the condition. That said, blacking out is not a sign of alcohol use disorder unless someone is blacking out frequently. In fact, 50% of all drinkers have experienced a blackout at least once in their lives. Still, blacking out even once is cause for concern and signifies an unhealthy relationship with alcohol.

What is the Difference Between Blackouts and Passing Out?

Blacking out and passing out are used interchangeably by some people but the two conditions are not the same. Blacking out is a loss of memory whereas passing out is a loss of consciousness. That said, blacking out and loss of consciousness can happen at the same time or during the same evening.