Drunkenness occurs when a large amount of alcohol enters a person’s bloodstream. The alcohol causes many visible symptoms. The drinker’s speech will slur, their balance will become impaired, and their face and eyes may redden. Emotionally, their feelings can easily range from euphoric to melancholy.

Alcohol is processed by the liver after being ingested. An ounce of alcohol can be metabolized between every sixty to ninety minutes. When the liver is unable to keep up with the amount of alcoholic drinks entering the body, the central nervous system becomes depressed. Sleepiness and a clear lack of energy are two of the biggest indicators that alcohol is having an effect over every part of the body.

Alcohol poisoning is an extreme level of drunkenness exhibited by nausea, vomiting, extremely shallow breathing, and unresponsiveness. These are the emergency symptoms of respiratory distress. The body has become unable to process the alcohol and is beginning to slip into a coma.


Science of Getting Drunk infographic

What’s happening inside your body when you’re getting drunk?

A drink is consumed; it passes down the esophagus, through the stomach and into the small intestine.  The bloodstream rapidly transports the ethanol throughout the body, where it is absorbed into the body issues in proportion to their water content.  The vast majority of alcohol enters the bloodstream through the walls of the small intestine, and your blood alcohol levels increases when your body begins taking in alcohol faster than it can release it.

The liver detoxifies and removes alcohol from the blood.  A minute amount is excreted unchanged in the breath, sweat, and urine.   How quickly it’s absorbed and metabolized by the liver depends on the alcoholic content of the drink, and whether you have eaten.  The kidneys direct fluids straight through the bladder, causing frequent urination and accelerating the loss of fluid from the body… eventually causing dehydration, which leads to a hangover.   Un-metabolized alcohol is distributed throughout the body, causing the drunkenness you feel until the alcohol makes its way through your body.

What’s happening inside your brain?

We’re all familiar with the signs of drunkenness:  slurred speech, memory lapses, falling down… All occur because of the way alcohol affects the brain and central nervous system.


Alcohol increases the effects of the inhibitory transmitter GABA in the brain, causing sluggish movements and impaired speech.  It also inhibits the excitatory neurotransmitter glutamate; by suppressing this stimulant, alcohol causes a similar type of physiological slowdown to GABA.  In addition, alcohol increases the amount of the chemical dopamine in the brain’s reward center, which creates the feeling of pleasure.

Regions of the Brain:

Cerebral cortex:  Alcohol depresses the behavioral inhibitory centers, making the person more likely to do things they wouldn’t otherwise do; it slows down the processing of information from the eyes, ears, mouth, and other senses; and it inhibits the thought processes, making it more difficult to think clearly.

Hypothalamus and pituitary gland:  These coordinate automatic brain functions and hormone release.  Alcohol depresses nerve centers in the hypothalamus that control sexual arousal and performance.  Although sexual urge may increase, sexual performance decreases.

Cerebellum:  Alcohol affects this center of movement and balance, resulting in the staggering, off-balance swagger we associate with the “falling-down drunk”.

Medulla:  By acting on the medulla, alcohol induces sleepiness. It can also slow breathing and lower body temperature, which can be life threatening.

Why do I feel shaky and sleepy?

Low blood glucose levels are responsible for the shaking feeling, heaving sweating, dizziness, and blurred vision.  Low glucose levels also result in feeling tired.

Why do I feel so sick after being drunk?

When the liver is metabolizing alcohol, it produces acetaldehyde, a vinegar-like substance that has toxic effects on the liver, brain, and stomach lining, resulting in headache, nausea, vomiting, heartburn, and a general feeling of unwellness.  Alcohol also plunders our stores of vitamins and minerals, which need to be in the correct balance for the body to function normally.  In particular, it affects our stores of calcium, sodium, and potassium.  Dehydration affects the concentrations of these ions, resulting in thirst, muscle cramps, dizziness, and faintness.

The liver needs water to get rid of toxins from the body, but since alcohol acts as a diuretic, there will be insufficient amounts in the body… so the liver is forced to divert water from other organs, including the brain, which causes headaches.

Why am I hungry when I’m drunk?

To overcome the feeling of lethargy and tiredness, the body will be craving a carbohydrate boost, which is why many people feel hungry when drinking.

Will I really sleep better if I’m drunk?

Though some people feel a “nightcap” helps them fall asleep, scientific evidence suggests the quality of sleep will drop due to dehydration.


  1. this information has really quenched my desire to understand how alcohool affects human behaviour. big shout out to the blogger.

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