You already know what causes hangovers… it is the digestion of alcohol. You take a sip of your favorite drink and swallow it. The liquid goes down your esophagus and enters your stomach. So far you are probably pretty safe unless you are drinking Everclear or 151 straight up, in which case there is a good chance you have already irritated your throat. Now the fun begins…
When the alcohol hits your stomach it immediately begins to irritate the stomach lining. Alcohol also causes your stomach to secrete something called hydrochloric acid. If you fill your belly with too much booze this acid will trigger a message to your brain that you are harming yourself. This message comes in the form of feeling nauseous. Although puking is never that fun, it might be in your best interest if you have been drinking heavy because there will be less alcohol in your system to process.
If you do keep the liquor down it eventually enters your bloodstream, which triggers your pituitary gland to stop the creation of a chemical called vasopressin. I’ll spare you from the biology lesson here, but in short this chemical tells your body it is time to start releasing fluid. This loss of fluid is also what causes hangovers. This is what us drinkers call “breaking the seal”. Most of the liquid you consume from this point forward goes directly to the bladder instead of getting absorbed into your body… leading to dehydration.
Your body will now try to protect itself. In fact, it will try to let you know that you are getting dehydrated, often times in the form of a dry mouth. Unfortunately these signals usually cause you to drink more alcohol (instead of water). Your internal organs will attempt to replenish themselves by stealing water from your organs (including your brain). When your brain is robbed of fluid it shrinks and pulls on membranes which connect to your skull. Hello headache!
As you continue to piss the night away (pun intended) salt and minerals are also lost.
Loss of Glycogen
Furthermore, your continued consumption of alcohol begins to turn your body’s supply of glycogen into glucose and sends it (along with salt and minerals) out of your body in your pee. This loss of electrolytes and glycogen is also what causes hangovers, subsequently limiting your energy reserves in the morning.
Reduction of Glutamine
If you have really tied one on you probably will not get restful sleep. When alcohol enters your bloodstream it reduces a protein called glutamine. However, once you stop drinking your body will try to compensate for this reduction in glutamine by producing more. The surplus of glutamine created from this yo-yo effect now over-stimulates your brain and messes with your REM sleep (severe glutamine rebound can even cause tremors, anxiety, restlessness, and increased blood pressure in some people).
To put it bluntly, if you feel poisoned in the morning it’s because you have basically just poisoned yourself. Congeners, acetaldehyde and (in some instances) histamine are also what causes hangovers.
There is some truth in the claim that what causes hangovers is what type of alcohol you drink. Red wines and dark liquors such as brandy, scotch, tequila, bourbon and whiskey contain the greatest amounts of congeners. White wines and clear liquors such as gin, vodka, and clear rum will have fewer congeners comparatively. As a result some people will find that they feel worse the next day from consuming dark colored alcohols compared to lighter colored alcohols. Want to learn more about what causes hangovers regarding different types of alcohol? Click here.
As mentioned above, when alcohol is finally broken down in your liver you are left with a toxin called acetaldehyde. Acetaldehyde is actually more toxic than the alcohol you’ve consumed, so it is quickly attacked in your body by two compounds (acetaldehyde dehydrogenase & glutathione) working together to form acetate. If you only drank a small amount of alcohol you’ll be okay… but you probably would not have read this far if you are a tea toddler and unfortunately for you, your liver only has a limited amount of glutathione. So guess what? At this point you and your liver are now enemies. You can learn a little more about alcohol metabolism here.
Lastly, histamines (which are found in the skins of grapes) will increase the severity of hangover symptoms in some people (if they are sensitive to histamines). Red wine will affect a histamine-sensitive drinker more than white wine because red wine has spent more time in contact with grape skins.
And that my friend is what causes hangovers.