We all know we're going to get a hangover after a night of alcoholic partying—but what's really happening when you drink?

How can one genre of beverages wreak so much havoc on your behavior and on the morning after? Science has the answers.




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Anything you drink slithers down your esophagus, into the stomach, and then into the small intestines.

Consider them the waiting room en route to being drunk.

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The walls of the small intestine are porous, so the alcohol that hasn't been absorbed into any former food lingering in your stomach or the intestines starts to seep out and into the blood stream.

Your circulatory system is pretty speedy. So when it picks up the alcohol, it moves it around pretty rapidly—leading to you feeling drunk quite quickly.

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The alcohol has undergone very little processing by your body at this point—that's actually how breathalyzers work.

They're not measuring how much alcohol you put down your throat, they're measuring how much alcohol is seeping back into your lungs and then from your lungs into your circulatory system, hence the term "blood alcohol."

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Meanwhile, your liver is trying to mediate the situation by detoxifying the alcohol that's now in your bloodstream. The speed with which the liver can do that is based on the type of alcohol you consumed, the mixer it was consumed with, and whether there was anything in your stomach to absorb some of it and re-direct it to the digestive system.

That's why a shot of bourbon straight up on an empty stomach is going to get you drunk faster than a mixed drink or a carb-laden beer—your liver can't cope with all that liquor at once, so more of it stays in your bloodstream longer.

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The liver is trying to be super helpful by detoxing you and metabolizing the alcohol into nutrients the body can process and dispose of.

Unfortunately, the liver's detox process results in the creation of acetaldehyde. Acetaldehyde is the real culprit of the worst hangovers. It's a toxic, vinegar-like substance that your liver, stomach lining, and brain don't like—thus the horrible feelings of nausea, vomiting, heartburn, and part of the headaches you feel the morning after.

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The detoxed alcohol then makes its way back into the digestive tract and to your kidneys—they're in charge of any liquids that make their way through the body. The kidneys direct their liquid bounty out to the bladder.

In an effort to aid the liver, they might have even scooped up some unprocessed liquor before it looped its way through your blood and liver. This is why drinking alcohol also means tons of pee-breaks throughout the night.


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You're not only just peeing out straight alcohol or detoxed alcohol. Your body wants to get the bad bits out of you ASAP.

To trigger the mechanism that lets you know its time to go to the bathroom—your body pulls out any hydration it can and sends it to the bladder.  This is why drinking makes you dehydrated. And it's especially why you have that headache the next morning. Your brain is the first thing to feel the pain of not having had enough water. Never go to bed after drinking without first guzzling some straight H2O.

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Okay, so that's how you get drunk. But what do the biological and medical sciences have to say about why alcohol has the effect on us humans that it does?

The answers are mostly all in our heads. Literally.

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Alcohol messes with the neurotransmitters that zoom around our brains directing our conscious and subconscious emotions, actions, and motor skills.

The neurotransmitters glutamate and GABA translate alcohol into the sluggish movements and speech typical of being a bit more than tipsy. The changes wreak havoc on the cerebellum. That's the back bit of our brain that's our center of balance and movement. Messing with the cerebellum means a lot less dignified walking, and a lot more confused stumbling and shambling.

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The cerebral cortex at the front of the brain simultaneously gets depressed by alcohol. Slowing things down there means less thinking clearly and less inhibitions to what you do and say.

It also means that your capability to process incoming information from your eyes, ears, and other sensors is stunted.

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The hypothalamus and pituitary gland (the tiny red bits in the image) also get depressed by alcohol and slow down.

Normally, they control the release of your hormones. And without their vigilance, your hormones are free to pounce on whatever hottie crosses your path. Between the hormone burst and the dopamine also released by the presence of alcohol—your pleasure centers are all quite happy. That's both why you like drinking and why you like to get it on after you've had a few drinks (despite the fact that, ironically, the alcohol also limits all of our motor skills in the bedroom department).

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Meanwhile, pressure from alcohol's presence in the body and its affects on the system result in the medulla's crackdown on everything while your body tries to process out the toxic bits of the alcohol (and the toxins created by detoxifying it).

This means that your heart rate gets lowered and your body temperature is turned down.  Even your breathing is slowed as the body tries to regulate energy towards detoxification. Combined, this means that the medulla basically puts the body (and therefore you) to sleep while it works out the new eternal kinks you guzzled at the bar.

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Your late night desire for pizza, fried things, and french fries is a response to that sleepiness.

Your body knows a carbohydrate boost will give the body more energy to process everything —and keep you awake long enough to stumble home or survive the Uber ride back.

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Want to know more about the science of being drunk and its after-effects? Or want to measure up against the stats on how much it should take to get you drunk?

Check out the ultimate alcoholic infographic—it will walk you through it. And you could probably turn it into a poster for your dorm room/grown up adult man-cave.