Surprising Reasons for Your Hangover, According to Science

Surprising Reasons for Your Hangover, According to Science

Why you feel so lousy after a night of drinking—plus tips for staying hangover-free.

Whether you're having beers with a buddy or celebrating Wine Wednesday with your BFFs, a choice beverage can help make for a memorable evening. The potential problem: drinking more than the recommended daily amount could land you with some brutal next-day symptoms.

Before you try any questionable home remedies, it could help to know why hangovers happen in the first place. Here’s the science behind hangovers, plus proven tips on how to make the morning after as painless as possible.

Why you get hangovers
Researchers have identified a few possible explanations for hangovers, although more studies are needed to determine the exact cause. Various physical processes take place when you drink alcohol, a number of which may contribute to your symptoms when the buzz wears off:

  • Dehydration: Alcohol is a diuretic, or a substance that causes you to urinate more frequently. If you lose fluids faster than you’re able to replace them, you can become dehydrated. Dehydration may lead to hangover symptoms like headaches, dizziness, dry mouth and mental fog.
  • Inflammation: People with hangovers have been found to have higher levels of certain cytokines in their blood. Cytokines are proteins that your immune system releases when it detects a threat. They’re a key part of the inflammation process, which sets your body’s defenses in motion. Inflammation causes pain, swelling and redness around injuries; body aches and fevers when you have the flu. When the “threat” to your body is alcohol, inflammation may be to blame for symptoms like aches, tiredness and irritability.
  • Toxin buildup: When alcohol breaks down in your system, it releases a harmful chemical called acetaldehyde. This toxin builds up in your brain and tissues, causing flushing, nausea and a number of other symptoms.

Dark alcohols such as whiskey and cognac contain substances called congeners as well. Congeners are chemicals that form during the alcohol fermentation process and make hangovers worse. They also take a longer time to leave your system than alcohol, which is why hangovers from dark beverages tend to linger.

Why some people are more sensitive to hangovers
Is your morning-after headache harsher than your friend’s—even after drinking the same amount? If so, there may be a number of factors at work. The severity of hangovers depend on how much and how quickly you drank, along with:

  • Your age: As you get older, your liver, kidneys and immune system all work at a slower pace, causing alcohol and its toxins to stay in your system longer.  
  • Your gender: Drink for drink, alcohol tends to affect women more than men.
  • Your genetics: Certain people inherit a genetic mutation, which causes their body to turn alcohol into acetaldehyde at a faster rate than the average person. That makes the toxin build up in their system more quickly than they’re able to eliminate it through urine. They may even start to experience symptoms like flushing while they’re still drinking. People with East Asian heritage are prone to this condition.
  • What you’ve had to eat that day: You’re more likely to get drunk and wind up with a nastier hangover if you drink on an empty stomach. That’s because alcohol is absorbed from your digestive tract and into your bloodstream faster when there’s no food to slow it down.
  • Which drinks you choose: There may be something to the popular wisdom that says mixing liquors is a mistake. Since each type of alcohol contains different chemicals and stays in your system for varying lengths of time, blending them together may open you up to a longer list of symptoms.

Commit to one type of alcohol for the evening. Opt for clear alcohols like vodka or white wine to avoid headache-inducing congeners. If you get bored, mix juices, sodas and craft cocktail ingredients into your beverage, rather than other alcohols. But choose regular soda instead of diet if possible—the sugar in regular soda slows down the rate at which alcohol is absorbed into your bloodstream. That means you may get drunk faster if you mix with diet soda.

Also, alternate alcohol with water throughout the night to protect against the effects of dehydration. Electrolytes are minerals like calcium and potassium, which your heart, kidneys and other organs need to carry out key functions. Sip on a sports drink or chicken broth to replenish your stores.

Tips for bouncing back the next morning
Hangovers are unpredictable: You could wind up with one despite your best efforts to drink wisely. That’s because there’s so much variety when it comes to beverage choices, and each alcohol may affect every person differently. If you wake up feeling under the weather, here are some tips to get you through the day:

  • Skip the Bloody Mary: Drinking the next morning will only make you drunk again. You might feel better briefly, but a hangover will still be waiting for you.
  • Hydrate instead: Drink plenty of water to ease dehydration symptoms and help you flush toxins out of your system. 
  • Don’t fall for popular “hangover cures”: There are no science-backed home remedies or products to cure a hangover. Instead, reach for an anti-inflammatory medication like ibuprofen or naproxen. These over-the-counter meds can relieve your headache and body aches. But don’t take acetaminophen (Tylenol)! Combining acetaminophen and alcohol interferes with your liver’s ability to work properly and could cause you to overdose.

From bacon grease to Tabasco sauce, there are plenty of rumors about how to fix a hangover. But the only way to truly treat your symptoms is with fluids, anti-inflammatory meds and rest.

Medically reviewed in January 2018.

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