What causes a hangover? A hangover is caused by a combination of things, including acetaldehyde poisoning, dehydration, inflammation, irritation of the stomach, low blood sugar, and lack of sleep.
As an interesting aside, the word “hangover” only became associated with the morning after drinking too much in 1904. It was used in the Foolish Dictionary, under the entry for Brain. It said “usually occupied by the Intellect Bros … but sometimes sub-let to Jag, Hang-Over & Co.” The word had always been used to refer to something left over, but from this point on it started to become used mainly for leftover alcohol.
Drinking can be fun, but nobody enjoys the feeling that comes the morning after. At best, it can be a mild headache, at worst, it can be a completely debilitating experience. So, what causes it?
Alcohol is a toxin, and the body tries to remove it as quickly as it can. The alcohol is absorbed from the intestines into the blood, and it travels along the portal vein to the liver. Once there, the liver goes to work and an enzyme called alcohol dehydrogenase is activated to metabolize the alcohol. The goal is to make the alcohol more water soluble so it can be removed from the body by the kidneys. Alcohol dehydrogenase turns the alcohol into acetaldehyde, which is easier to remove from the body, but is 30 times more toxic for the body than the alcohol itself. Because of this, the liver then uses another enzyme called acetaldehyde dehydrogenase to turn the acetaldehyde into acetic acid as quickly as possible. Acetic acid is harmless, and it gets converted into carbon dioxide and water. If you only have one drink in an hour, the liver will be able to remove all of the alcohol, and you won’t feel the effects, but more than that, and the liver won’t be able to cope. The amount of toxic acetaldehyde will build up in the body. Some people have more of the second enzyme than others, which means they can handle more alcohol, but even their livers can be overwhelmed.
The liver’s attempts to get rid of the toxin in the body account for a lot of the symptoms of a hangover. The first is a headache, which is usually caused by dehydration. The liver removes poisons from the blood and passes them to the kidneys to be removed from the body. To do this, the kidneys produce more urine, leading to dehydration, which can cause headaches.
However, most of the symptoms come from the toxicity of the acetaldehyde itself. If the amount of toxin overwhelms the body’s ability to remove it, the immune system gets triggered. This causes a lot of inflammation in the body. When our inflammatory response is triggered, the blood vessels dilate to allow more fluid to enter the affected areas. This increase of blood flow near the skin is the reason why people who are drunk often have a red face. The dilated blood vessels can activate nerves near the brain as well, causing headaches. Inflammation in the stomach and intestines causes the nausea and the stomach irritation. This is a natural response to remove a poison from the body.
Many of the other symptoms of a hangover are side-effects of this. Too much alcohol disrupts the production of melatonin, which regulates our sleep-wake cycle. Drunk people often cannot reach the necessary REM sleep, and they wake up throughout the night. Being unable to sleep adds to the headache and the generally bad feeling of a hangover.
There is also a lot of evidence that congeners, which are produced in the fermentation process, or sometimes are added to the drink play a part. Generally, the more congeners an alcoholic drink has, the darker it is. That is why hangovers from red wine and brandy tend to be worse than those from vodka.
There are a lot of remedies for a hangover, such as a strong cup of coffee, but in actuality, there are none that will work. The hangover is caused by the toxin still in the body, and the only cure for a hangover is to wait for the liver to remove it all. This is why people generally start to feel a little better in the early afternoon. If you only had a bit too much to drink, your liver will take time, but it will fix you. If you have drunk far too much in a very short space of time, the enormous amount of acetaldehyde in the blood, and alcohol’s depressing effect on the central nervous system could mean that the vital organs start to shut down. This is called alcohol poisoning, and medical attention is vital. And this is what I learned today.
Sources
https://www.nm.org/healthbeat/healthy-tips/the-science-of-a-hangover
https://en.wikipedia.org/wiki/Hangover
https://www.etymonline.com/word/hangover
https://www.addictioncenter.com/alcohol/hangover
https://www.ucdavis.edu/health/news/why-do-some-people-get-headaches-drinking-red-wine
https://my.clevelandclinic.org/health/diseases/16640-alcohol-poisoning
Photo by Andrea Piacquadio: https://www.pexels.com/photo/young-man-in-sleepwear-suffering-from-headache-in-morning-3771115/