Why forget when drunk

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. Drinking alcohol without food gets you intoxicated much faster and increases your risk of blacking out. 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.

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.

Some studies suggest that women are more likely to experience an alcohol blackout than men even when they drink less. Although alcohol is legal for those over 21, its frequent and heavy use is dangerous. By Alexandra Sifferlin. Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Please attempt to sign up again. Sign Up Now. An unexpected error has occurred with your sign up. Please try again later.

Check here if you would like to receive subscription offers and other promotions via email from TIME group companies. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Service and Privacy Policy. He found that out of alcoholics, more than 60 experienced regular blackouts , some total and some fragmentary.

He also revealed that individuals experiencing a blackout can act in a remarkably coherent manner. But 30 minutes later, these events were forgotten. In one he showed participants pornography, then asked detailed questions about what they had seen.

In another, with a frying pan in hand, he asked individuals if they were hungry. When they answered, he told them that the pan had dead mice inside. The drunk subjects had forgotten these memories after 30 minutes and could still not recall the events the following day. They could, though, recall these events up to two minutes later, revealing that their short-term memory was working. For many decades it was believed that only alcoholics reached the state of being blackout drunk, we now know that is not the case Credit: Getty Images.

Though these experiments were performed with alcoholics, they set the stage for understanding how even non-alcoholics act during a blackout. They remain influential in part because today — for obvious ethical reasons — scientists cannot ply participants with alcohol to induce memory loss. They must largely rely largely on questionnaires of past events instead.

That chunks of memory are completely lost during a blackout goes some way into revealing what is going on in the brain. People with severe damage to this area cannot create new memories. Alcohol therefore shuts off brain circuits central to making episodic memories memories of specific times and places , explains White, who has studied the process on a cellular level with rodent brains.

We now also know more about other factors that influence blackouts , such as drinking on an empty stomach or when sleep deprived. Another major risk has to do with how fast alcohol is consumed, as the quicker we gulp the faster our blood alcohol level spikes.

A blood alcohol level of between 0. That level could be reached by having 15 or more standard UK drinks over four hours, depending on sex and body weight. Blackouts are more common among college students and women Credit: Getty Images. Blackouts are more common in people with lower body weights. Women also experience blackouts more often. They are smaller on average than men and have a higher percentage of body fat, which means their bodies have less water to dilute the alcohol they drink — so their blood alcohol level rises faster.

In , Amie Haas of Palo Alto University in California found that women would routinely blackout with three fewer drinks than men. Aside from the sex differences, there could be a genetic component to who is more likely to blackout. Individuals whose mothers had a history of alcohol problems were found to be more at risk. Another study, this time on more than 1, pairs of twins, found that a genetic link accounted for half the blackouts experienced.

The genetic difference seems to play out in the brain, too. One longitudinal study of adolescents aged , led by Reagan Wetherill of the University of Pennsylvania, showed that certain individuals who later went on to abuse alcohol and experience blackouts, were less able to suppress their actions.

This could be seen on brain scans, even before they were drinking alcohol. Alcohol can shut off brain circuits important for making memories of specific times and places Credit: Getty Images.