What Causes a Hangover and How to Prevent the Pain

Woman lying in bed, turning off alarm clock

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The hangover, what a dreaded word! It brings chills to the bones and your head begins to throb just thinking about the possibility of waking up in the morning tired, nauseous, and just plain crappy. Yet, often enough, we do not think about this while we are having a good time with friends and ordering another old-fashioned or, worse yet, a Jäger bomb.

So, why do we get hangovers? How can we avoid them? How bad can it get? And what can we do when we have one? Those are the questions we are going to answer and that is really what you want to learn. That is why you are here, is it not?

Hangover Symptoms

How will you know if you have a hangover? First of all, you will know it when you have one. If you have never had a hangover, consider yourself lucky. 

There are common symptoms of a hangover. Hopefully, you will not suffer from all of these at once. If this entire list describes your current condition, tell everyone to leave you alone and go back to bed.

  • Dehydration and dry mouth
  • Tiredness and trouble sleeping
  • Headache, nausea, and weakness
  • Anxiety, irritability, and pessimism
  • Difficulty concentrating
  • Sensitivity to light and noise
  • Suspension of the laws of gravity

10 Factors That May Cause a Hangover

There are a number of factors that play a part in whether or not you will suffer from a hangover after a night of drinking. Many of the causes are obvious and most of us know what our own limitations are.

It goes without saying that the one true way to avoid a hangover is to avoid or severely limit the amount alcohol you consume. Other than that, there are no guarantees.

  1. Not Enough Water. The ethanol contained in alcoholic beverages has a dehydrating effect which causes headaches, dry mouth, and tiredness. This effect can be lessened by drinking plenty of water before and throughout your night of drinking.
  2. Effects on Your Liver. Your liver breaks ethanol down with the aid of enzymes produced by liver cells. These chemical reactions do many things that include impairing the liver's ability to supply glucose to tissues, in particular to the brain. Glucose is responsible for the brain's energy and the lack of it results in fatigue, weakness, moodiness, and decreased attention.
  3. Congeners. Congeners are the by-products of the process of alcohol fermentation and exaggerate the symptoms of a hangover. The more congeners consumed, the worse a hangover is likely to be. Dark spirits such as brandywhiskey, and red wine contain more congeners than lighter spirits like vodka and white wine. Likewise, cheaper spirits have had fewer of these impurities removed through filtration and are more likely to cause a hangover. This means that cheap vodka may actually affect you more than a high-end whiskey.
  4. Sweet Drinks. Some people believe the sugar in sweeter cocktails contributes to the severity of hangovers. There may be something to this. The more likely explanation is that sweeter drinks tend to mask the alcohol's flavors and cause our taste buds to crave more sugar at the same time. This inadvertently encourages us to drink more.
  5. Smoking. Smokers (and even some non-smokers) tend to smoke more when they are drinking. This can lead to nicotine poisoning which will also worsen hangovers.
  6. Genetics. Some people are genetically lucky when it comes to hangovers and will rarely if ever, suffer the effects. Others have a predisposition to suffer and the symptoms can be more severe and frequent. It should not take you long to figure out where you fall on this spectrum.
  7. Weight Is a Factor. The less one weighs, the more that person will feel the effects and the after-effects of alcohol at lower amounts. This is one reason why women tend to get drunk faster than men and may have a harder time with hangovers.
  8. Your Age. The older you are, the more likely you are to have a severe hangover. This is usually not a factor because we tend to take it a little easier as we learn from the mistakes of our younger years. Of course, this is not always the case and you have been warned.
  9. Is It in Your Head? There is something to be said about psychosomatic effects. If you think you will get a hangover, you will probably get one. Look on the bright side and save yourself: it's no guarantee, but it may help.
  10. Take It Easy. Finally, the more you drink or the more you guzzle in a short time, the worse your hangover will be. This one should be obvious, but all of us could use a reminder from time to time.

Preventing a Hangover

Before and throughout your night of drinking, there are some wise choices you can make that may lessen the effects of your misery the next day. Who knows, you may even avoid one completely, though the only way to guarantee that is to not drink alcohol at all.

Before You Drink

  • Eat. Fill your stomach with a healthy meal of starches and essential vitamins and minerals. The food will absorb the alcohol and lessen its effects on you. If you decide a greasy bar burger or drippy pizza is your idea of a good meal, you may regret that idea. The grease can mix the wrong way with liquor and carbonation and you just may end up staring at the toilet bowl later in the evening.
  • Hydrate: Drink a lot of fruit juice and water now. Think of it this way: for every glass of non-alcoholic beverage you drink now, you will save yourself from having to drink two glasses in the morning to rehydrate.
  • Prep: Prepare your favorite hangover remedy and place it in an easy to open container in the fridge or next to your bed. If you do overindulge, the last thing you will want to do in the morning is gather ingredients, mix things or, worse yet, run the blender.
  • Prickly Pear: A clinical study from 2004 suggests that drinking prickly pear fruit extract several hours prior to drinking will reduce the symptoms of a hangover.
  • OTC Fixes: Try one of the many anti-hangover remedies found at convenience store registers and drug stores. 

While You Drink

  • Eat: Grab a bite to eat at the bar. This is when greasy fries would be okay because it is a snack that will keep your stomach full and add extra material to absorb the alcohol. Bar peanuts, popcorn, or any type of food will do the job.
  • Quality: Choose booze carefully. Again, dark spirits contain more congeners; light spirits fewer; cheap liquor more. More impurities equal more headaches. Stick with quality light-colored drinks most of the night to reduce your hangover chances.
  • The Order of the Drink: Memorize this rhyme and abide by it, it may save you a lot of pain. "Liquor before beer, never fear. Beer before liquor, never sicker." Some will say that it is a myth, and that may be so. However, no matter which order you drink in, quantity is the biggest factor.
  • Alternate Alcoholic With Non-Alcoholic Beverages: This trick will slow your alcohol consumption down while giving you something to drink. Choose water, fruit juices, or lightly carbonated beverages like tonic or club soda and drink one for every alcoholic drink you consume. If you are worried about what your friends may think, order a mocktail or dress up a straight virgin beverage with a garnish and lie. Call Sprite or 7-Up with a​ lime wedge a vodka tonic or orange juice a Screwdriver or cranberry juice with a lime a Cape Codder. They are probably too drunk to know the difference and who cares anyway. You will feel so much better in the morning than they will.
  • Consume Less Than One Drink per Hour: Your liver breaks down alcohol at the rate of one beer per hour. Spreading your drinking out over many hours will give your body a chance to keep up with you. Remember that is beer and not liquor. There is a big difference in the alcohol content of the two, so if you're a cocktail drink, slow down even more.
  • Before Bed: Once you make it home and before you crash on the bed, force yourself to drink a glass of water and take some vitamin B. This is also not the time to take any headache medicine (acetaminophen, ibuprofen, aspirin, etc.) as they could seriously damage your liver.

Important: If you experience tremors, stomach pain, or see blood in your vomit, seek professional medical attention IMMEDIATELY. You may have severely overdone it and should go to the emergency room right away.

Article Sources
The Spruce Eats uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. National Institutes of Health. Hangovers. Updated March 2019.

  4. Jackson KM, Rohsenow DJ, Piasecki TM, Howland J, Richardson AE. Role of tobacco smoking in hangover symptoms among university students. J Stud Alcohol Drugs. 2013;74(1):41-9.  doi:10.15288/jsad.2013.74.41

  5. Wiese J, Mcpherson S, Odden MC, Shlipak MG. Effect of Opuntia ficus indica on symptoms of the alcohol hangover. Arch Intern Med. 2004;164(12):1334-40.  doi:10.1001/archinte.164.12.1334

  6. Cleveland Clinic. Hangover: prevention. Updated October 2, 2017.