What Happens to Your Brain If You Drink Too Much?

For many of us, the festive season is a time for overindulgence: too much sugar, too much TV and too much alcohol. But, after a month of Christmas parties, seasonal cocktails and family festivities, you might be starting to wonder what all of this festive cheer is doing to your body.

Everyone deserves to let their hair down every now and then, but the throbbing in your frontal lobe after one too many eggnogs might have left you wondering "what is all of this binge drinking actually doing to my brain?"

Newsweek spoke to experts to find out.

What Is Binge Drinking?

The Centers for Disease Control and Prevention (CDC) defines binge drinking as drinking five or more alcoholic beverages in one sitting for men and four or more for women. It is the most common pattern of excessive alcohol use in the U.S., with one in six American adults admitting to doing so.

Consuming large quantities of alcohol in a single sitting can be dangerous and is associated with unintentional injuries and alcohol poisoning. It can also have longer term effects due to the way alcohol interacts with our body and brain.

What Are the Short-Term Effects of Alcohol on the Brain?

When we drink, the communication pathways in our brain get interrupted, affecting our balance, memory, speech and judgment. "The acute effects of alcohol are quite complex because it affects so many neurotransmitters," Greg Sutherland, a neuropathologist at the University of Sydney, Australia, told Newsweek.

Sutherland said the major effects of alcohol were as a sedative because of how the molecules inside it interact with the communication pathways in our brains.

This is because the ethanol in the alcohol blocks receptors in the brain that are involved in exciting your neurons, causing the brain to function more slowly. At the same time, alcohol also activates the receptors that are involved in making us feel calm and sleepy, which slows the brain down even more.

Because of this slowing-down of the brain, alcohol can be described as a depressant—something that reduces brain activity. One area of the brain that is particularly sensitive to these effects is the cerebellum, the part of the brain that controls coordination and movement. As a result, we quite literally become tipsy and lose our sense of balance and coordination.

Alcohol also causes our brains to release dopamine, which is responsible for the buzz you feel when you knock back your first cocktail of the night. Combined with the calming effect of slowing down our nervous system, this can make us feel more confident and relaxed.

Henry Kranzler, a professor of psychiatry at the University of Pennsylvania, said that this effect was correlated with alcohol consumption. "As the brain's alcohol concentration increases [...] the effects increase," he told Newsweek. "These effects are also related to the intensity and length of alcohol exposure."

He said the effects of alcohol on the brain lag behind ingestion by about 40 minutes, so it is easy to overdo it without realizing you have already had too much.

How Does Alcohol Affect the Brain in the Long Term?

"It is well documented that regular heavy drinking adversely affects both brain structure and function," Kranzler said.

In a paper published in Nature Communications in March 2022, Kranzler and his colleagues demonstrated how even moderate drinking can impact the brain. Remi Daviet, a professor at the Wisconsin School of Business and first author on the paper, said these effects can impact our behavior: "Repeated exposure to high levels of alcohol leads to inflammatory reactions in the brain resulting in potential neuronal damage and cell death," he told Newsweek. "Ultimately, this can affect behavior and impair cognition in the long term."

Daviet said that these effects can be even more severe if alcohol is consumed while the brain is developing. Our brains change a lot during our teenage years and are particularly vulnerable to the neurological effects of intoxication, especially when it comes to learning and memory.

The Dietary Guidelines for Americans recommends that adults of a legal drinking age drink no more than two glasses a day for men and one for women. However, even this moderate consumption can impact brain structure. "We see that long-term repeated exposure to two small drinks or more a day is associated with reduced gray and white matter in the brain," Daviet said. "This is exponential, every additional drink is associated with more damage than the previous one."

Gray matter contains the control centers of the cells in our brains while white matter contains the fatty extensions that extend from each brain cell and connect our neurons together. A loss of gray matter can result in neurodegenerative diseases, like Alzheimer's and dementia, while a loss of white matter can disrupt the flow of information between different parts of the brain, resulting in impaired memory, balance and mobility.

While it is difficult to be sure that the association between drinking and loss of brain matter is a direct result of the alcohol, Sutherland said that there is some evidence that white matter in the brain can begin to recover if an individual abstains from drinking alcohol.

"We are currently working on what happens to the white matter," he said. "This is made up of axons–parts of neurons that connect between different regions of the central nervous system–and myelin. We know there is loss of myelin, but not why. Interestingly in those people who abstain there is a partial recovery of their myelin. So finding the mechanism could be really important."

Sutherland said the effects of alcohol on other organs, particularly the liver, can also affect the brain. "The liver is important because the build-up of toxins, like ammonia, is not good for the brain either," he said. This is because these toxins can build up in the blood and slowly make their way up into the brain, which can affect cognition and cause swelling.

"In some ways the indirect effects of alcohol are probably as bad or worse than direct effects for the brain," Sutherland said.

What causes Hangxiety?

Alcohol can also affect our mood. Anxiety after a heavy night of drinking is so common that it has earned its own name: hangxiety.

"Alcohol consumption can increase the presence of stress hormones and disrupt sleep," Daviet said. "Both of these can affect our emotional state."

Not everyone experiences hangxiety, but a study published in the Journal of Human Psychopharmacology in 2017 found that 22.6 percent of participants reported feeling anxious when they were hungover, while 34.2 percent reported feelings of depression.

People with social anxiety more often report feeling anxious the morning after a night of heavy drinking, and alcohol is known to make low-level anxiety worse due to its effects on our brain chemistry. You might also feel more anxious because you are dehydrated or have not had enough sleep.

Kranzler said that these effects are likely to be magnified in people who are regular heavy drinkers. "People who drink heavily for extended periods of time are also at risk of alcohol withdrawal, the most common symptoms of which are anxiety and tremor."

Is There Such a Thing as a 'Safe' Amount of Alcohol?

The negative impacts of alcohol on the brain are by no means the only health consequences of heavy drinking. Alcohol can damage your heart, liver, immune system and can increase your risk of developing several types of cancer.

However, Daviet said that, in terms of brain damage, drinking smaller amounts—below the standard recommendations–does not appear to have noticeable impacts on the brain. "I cannot say that there is a safe level of alcohol to drink, but in terms of brain damage, we couldn't detect any change at one small glass of 5-percent beer per day, or one bottle of wine per week," he said.

"We start seeing long-term differences once we reach and pass the daily consumption of a second glass."

Is there a health issue that's worrying you? Do you have a question about alcohol? Let us know via health@newsweek.com. We can ask experts for advice, and your story could be featured on Newsweek.

References

Ma H, Zhu G., The dopamine system and alcohol dependence, Shanghai Arch Psychiatry, April 26 2014, doi: 10.3969/j.issn.1002-0829.2014.02.002.

Luo J. Effects of Ethanol on the Cerebellum: Advances and Prospects. Cerebellum, August 2015, doi: 10.1007/s12311-015-0674-8.

Daviet R, et al., Associations between alcohol consumption and gray and white matter volumes in the UK Biobank. Nat Commun. March 4 2022, doi: 10.1038/s41467-022-28735-5.

Smith CC, et al., Lipidome changes in alcohol-related brain damage, J. Neuro. 26 October 2021, https://doi.org/10.1111/jnc.15530

National Center for Chronic Disease Prevention and Health Promotion, Excessive Alcohol Use, CDC Online, Last Reviewed July 11 2022

Lantman MS, et al., The impact of alcohol hangover symptoms on cognitive and physical functioning, and mood, Human Psychopharmacology: Clinical and Experimental, July 27 2017, https://doi.org/10.1002/hup.2623