Why Do I Blackout After Drinking Alcohol?

Woman in bed staring at an open window and wondering why she blacked outImage via twenty20photos

Blackout drinking is a scary and often unintended consequence of heavy or binge drinking. If blackout drinking, which is another phrase for alcohol-related memory loss, is something you experience with drinking, know that you are not alone. Research shows that as many as 50 percent of drinkers experience blackouts while drinking. 

We spoke to Dr. Kristine De Jesus about the causes of blackout drinking, what happens, why folx are likely to experience blackouts, and how much individuals think they can drink versus what happens physiologically.

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What is blackout drinking?

Blackout drinking is a term used to describe the effects of heavy alcohol use on the brain, specifically memory. Alcohol-induced memory issues are called amnesia, whereby a person experiences mild to complete memory loss during part of, or all of, a drinking event. In other words, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), blackouts produce a gap in memory transfer, known as memory consolidation, in the brain (in the area called the hippocampus).

The NIAAA defines heavy alcohol use as four or more drinks on any day, or more than 14 drinks per week, for a person assigned “male” at birth; and three or more drinks on any day, or more than seven drinks per day, for someone assigned “female” at birth. Binge drinking is defined as anything that brings the blood alcohol concentration (BAC) to more than 0.08 grams per deciliter. 

What’s particularly frightening and dangerous about blackouts is that a person is still conscious and can still engage with their environment—it’s just that the memory doesn’t make a recording of the event. Meaning, you wake up in the morning, either completely unaware of what happened the night before or only with a partial memory.

We asked Dr. Kristine De Jesus, PsyD, why blackouts occur. She explained, “A blackout occurs after a period of alcohol use when the concentration of alcohol in the blood is high and the body is trying to reduce harm by streamlining bodily functions.” 

This explains why a person is still conscious and can interact with their surroundings and even have detailed conversations. During a blackout, the body focuses on more critical functions than memory. 

“Recording new memories is not essential to sustain life, therefore the body prioritizes the functions of the autonomic nervous system over the production of recording memories to preserve life,” says De Jesus.

More specifically, she explains, blackouts are generally associated with high Blood Alcohol Content (BAC). 

“Blackouts generally occur when a person’s BAC is upwards of .14 (or in layperson’s terms, 14% of the blood contains alcohol). However, science suggests that this threshold for blackouts varies from person to person.” 

At this blood alcohol level, you might be feeling euphoric but progress to feeling unpleasant. You might find you struggle to walk or stand, and your judgment might be significantly impaired.  

You might sometimes remember snippets of the night before and other times recall nothing because there are two types of blackouts: temporary (fragmentary) or complete (en-bloc). 

Enbloc occurs at a higher BAC and involves complete memory loss during the drinking event, and fragmentary causes a partial memory loss where people may be able to recall some events from the night before with the relevant queues. Fragmentary blackouts are also sometimes referred to as brownouts. Researchers at Wetherill and Fromme (2016) state that fragmentary blackouts are more common, but you must exceed a BAC of 0.06.

Blackouts were a real part of my acute alcohol use disorder, starting in my late teens and continuing through to my early twenties. I recall waking up in the morning and having a routine of checking my phone to see who I’d called, texted, or interacted with. Next, I’d check to see if there were any pictures that gave a clue to where I’d been. Then I’d scour my apartment to try and patch together a picture of what had happened the night before. 

Why Blackouts Occur

In De Jesus’ opinion, many reasons cause blackout drinking and why some folks may even seek out harmful drinking as part of their coping methods. 

“While some people seek to blackout, to reduce or numb pain, to forget, or because society has normalized blacking out as a part of being intoxicated, in my experience, for most people, blackouts are an unintended consequence of over-consumption of alcohol,” says De Jesus. 

It also depends on social group, according to Dr. Aaron M. White. Blackout drinking is more often associated with social drinking, including college drinking. Certainly, in my case, I was socialized around heavy drinking. It was considered a rite of passage with my friends while growing up, and later with co-workers going to the bar after work was a way we all blew off steam. Drinking after work, and sometimes during a Friday afternoon or lunchtime, was the culture I was engaged in for nearly every job I had. It wasn’t until I started looking after my mental health that I realized I could reduce harm about my drinking.

How to Apply Harm Reduction to Blackout Drinking

I asked Dr. De Jesus what measures a person can put in place to prevent blacking out when drinking. Her suggestions include:

  • Limiting alcohol consumption to one serving of alcohol per hour (as that is the amount the body can metabolize and process through the liver without getting overwhelmed) 
  • Alternating between alcoholic and non-alcoholic drinks  
  • Being mindful of how much alcohol is in a drink (not all drinks are created equal and some have more alcohol than others)
  • Tracking the servings of alcohol one has consumed (make a note in your phone, or count the straws if you’re out).

“For those who struggle to limit their alcohol intake once they start drinking,” De Jesus says, “it may be helpful to replace alcoholic drinks with non-alcoholic options.”

A Note on Tolerance

While regular drinkers may think they can tolerate more alcohol than their friends, they could be ill-advised when it comes to what their bodies can handle. 

“People rarely understand the notion of tolerance,” contends De Jesus. She explained that individuals generally assume tolerance is how much alcohol a person can handle and often think that if a person has a high tolerance, their BAC is low compared to a person with a low tolerance. But they’re wrong. 

“BAC is a mathematical constant. The amount of alcohol, time in which it is consumed, gender, and weight of the person determine BAC, whereas tolerance is the time in which the body shows the impact of BAC.”

It’s important to be mindful that while you might not feel inebriated, your body could be telling you otherwise. That’s important to know when it comes to driving or anything else that requires you to be under a certain limit of BAC.

Blackout drinking doesn’t have to mean progressing to the acute stages of alcohol addiction, nor does it have to lead to a DUI. There are plenty of options to reduce harm now if you’re already experiencing blackouts. If you feel like you’re struggling with alcohol, it’s best not to try quitting cold turkey. Instead, consider reaching out to the Substance Abuse and Mental Health Services (SAMHSA) hotline or reading the CDC’s fact sheet on alcohol. If you’re interested in learning more about the effects of alcohol or are considering changing your relationship with alcohol, an online community of like-minded folx might be the perfect fit. At Tempest, we believe that all of you matters when you’re thinking about quitting drinking, and our online alcohol treatment program and community are designed to address it all.

About the Author

Olivia Pennelle

Located in Portland, OR, Olivia Pennelle (Liv) is a writer, journalist, and content strategist. She is the founder of the popular site Liv’s Recovery Kitchen, a site dedicated to providing the ingredients to live a fulfilling life in recovery. Liv also co-founded the podcast Breaking Free: Your Recovery. Your Way Liv is passionate about challenging limiting mentalities and empowering others to direct their own lives, health, and recovery. She found recovery in 2012 and her pathway is a fluid patchwork of what works for her. You can find her articles across the web on podcasts and publications, including The Fix, Ravishly, Grok Nation, STAT News, and The Temper.

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