What does blacking out mean — and what happens to your body? Experts explain

Experts say that blacking out means you have no memory of what you did or what happened. (Photo: Getty Images)
Experts say that blacking out means you have no memory of what you did or what happened. (Photo: Getty Images)

Andy Cohen made headlines after his alcohol-induced rant about former New York City mayor Bill de Blasio during CNN’s New Year’s Eve Live with Anderson Cooper and Andy Cohen. However, Cohen recently shared that he didn’t recall badmouthing de Blasio.

When Cohen and Cooper got in the car after the CNN special, “I saw on Twitter the rant I did about de Blasio,” the Watch What Happens Live with Andy Cohen host admitted during an appearance on Jimmy Kimmel Live! on Feb. 3, according to People. “And I did not recall — though it was about 40 minutes earlier — saying, ‘Sayonara, sucka’ to the outgoing mayor of New York.”

Cohen shared that he needed Anderson to confirm what he’d actually said. "I go, 'Oh, my God… I said, 'Sayonara, sucka'?" Cohen recalled with a laugh. 'And he goes, 'Yes, you did!'"

So what, exactly, happens when you have memory loss from drinking too much alcohol? Sometimes, it's called a blackout.

“A blackout means you are amnestic” — as in, experiencing amnesia — “for a period of time while you are intoxicated,” Dr. Anna Lembke, professor and medical director of addiction medicine at Stanford University School of Medicine, tells Yahoo Life.

Brad Lander, a clinical psychologist who specializes in addiction medicine at the Ohio State University Wexner Medical Center, tells Yahoo Life that “a blackout from alcohol occurs when alcohol interferes with the conversion of short-term memory to long-term memory. There is no memory of what you did or what happened.”

Lander explains that the hippocampus is a brain structure that’s responsible for converting short-term to long-term memory. “The hippocampus is essentially ‘shut down’ by high amounts of alcohol,” he says. “Also, alcohol reduces glutamate, an important neurochemical involved in memory formation.”

This is not to be confused with passing out, which experts say is “very different” from blacking out. “Passing out is a loss of consciousness from drinking too much,” says Lander. “Alcohol is a sedative, and if the brain is sedated enough, the person passes out. A blackout is a loss of memory. In a blackout, people are walking and talking but don’t remember it the next day.”

In fact, one of the most surprising characteristics of an alcohol-induced blackout is that people can actually appear to be aware and — on the surface — able to make decisions. “They might seem a little intoxicated, but with superficial interactions they would seem to be awake and also compos mentis,” says Lembke.

She adds: “They can even engage in complex behaviors, and they appear to be able to give consent and yet they can be not actually present for what’s happening in the way we usually think of in terms of consciousness. Later, when they emerge from a blackout state, they don't have any memory for that period of time.”

Others can experience what are called brownouts or partial blackouts — essentially, having “pieces of time missing but also vague memories,” says Lembke, which is possibly what Cohen experienced. It's what Lander calls a “spotty memory” of how your evening actually went. “The memory ‘stutters’ so bits and pieces can be recalled,” says Lander. “A complete, or total, blackout is no memory of the time at all.”

Certain drinking behaviors can put people at risk for blackouts. They’re more likely to happen to those who consume “large amounts of alcohol,” says Lembke, such as with binge drinking. According to the National Institute on Alcohol and Alcohol Abuse, blackouts also tend to happen at blood alcohol concentrations of about 0.16 percent — which is nearly twice the legal driving limit — and higher.

“The higher your blood alcohol, the more likely you are to have a blackout,” says Lembke. “And the faster you consume the alcohol, the more likely you are to have a blackout.”

Once you’ve experienced a blackout, “you’re more likely to have another,” says Lembke, and “some people are prone to blackouts for reasons we don’t understand.”

In addition to the health risks associated with consuming alcohol, which include high blood pressure, heart disease, stroke, liver disease and certain cancers, what effect do blackouts have on your health?

“Repeated blackouts can cause permanent damage to the hippocampus and reduction of glutamate,” explains Lander. “This leads to ongoing memory problems and, possibly, dementia.”

As Lembke puts it, “Alcohol is toxic to the brain.”

Alcohol-induced blackouts also leave people more vulnerable to sexual assault, as well as risky behaviors that can put a person’s health in danger. “When you're in a blackout, you appear to be conscious but you're not, so people assume you have the ability to make decisions that you don’t actually have,” says Lembke, including giving informed consent.

She adds: “You’re compromised in all the other ways you would be if you were not all there,” meaning not conscious. “It’s like you're on automatic pilot. And that might be OK if there are no storms, but if there’s a storm or the engine goes out, you’re not going to be able to engage your cortex and be able to make good decisions — or any decisions.”

Want lifestyle and wellness news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.