What is a hangover?
A hangover is when you have unpleasant physical and mental symptoms after drinking too much alcohol.
When does a hangover start?
Hangovers usually begin several hours after you stop drinking. The symptoms can vary in intensity, depending on the person and the type and amount of alcohol consumed.
How much alcohol causes a hangover?
Having more than one drink per hour can cause problems. Your body needs about an hour to metabolize, or process, one drink, which is:
- 12 ounces of regular or light beer — about one can (5% alcohol).
- 8 to 9 ounces of malt liquor or many types of craft beers — approximately half a pint glass (7% alcohol).
- 5 ounces of table wine — about one glass (12% alcohol).
- 1.5 ounces of liquor — approximately one shot (40% alcohol).
How common are hangovers?
Hangovers are very common in people who consume too much alcohol. In one study, researchers found that about 75% of people who drank excessively the night before reported hangover symptoms. The researchers concluded that 25% to 30% of people who drink may be resistant to hangovers.
Symptoms and Causes
What causes a hangover?
Alcohol causes hangovers — but it’s not simple. Drinking affects your body in several ways:
Direct effects of alcohol
- Dehydration: Alcohol is a diuretic. It causes you to pee more, so you lose a lot of fluid. (You can lose up to a quart of urine in the hours after having four drinks.) Alcohol also reduces the release of the hormone vasopressin. This hormone balances your body’s fluids. Dehydration causes thirst, fatigue and headaches.
- Electrolyte imbalance: Your body needs certain chemicals, called electrolytes, to perform at its best. Passing large amounts of urine throws electrolytes out of balance.
- Gastrointestinal problems: Alcohol irritates the lining of your stomach and intestines. It slows the rate of digestion, increasing fatty substances in your liver and stomach and pancreas secretions. All these processes lead to an upset stomach and nausea.
- Inflammation: Alcohol increases inflammation throughout your body. It can contribute to the general unwell feeling of a hangover.
- Low blood sugar: This effect usually happens in people who have alcohol use disorder. They may binge drink and fail to eat properly over a few days. As the body processes alcohol, it produces lactic acid. Lactic acid reduces blood sugar production, resulting in fatigue, sweating, hunger and shakiness.
- Disruption of sleep and other processes: While alcohol is a sedative and can promote sleep, hangover symptoms usually interfere with sleep. You may have insomnia as your blood alcohol levels get lower, so you feel fatigued. Alcohol also makes it difficult for your body to regulate its temperature and interferes with hormone production.
Effects of alcohol withdrawal
A hangover is a milder form of alcohol withdrawal. Both have similar effects and symptoms. Drinking helps you feel calm, relaxed and even happy. Your nervous system adjusts to these effects. But when the alcohol wears off, your nervous system has to readjust. You may end up feeling more restless, anxious and irritable than before you drank.
Effects of alcohol metabolites
When the body processes alcohol, one of the byproducts is acetaldehyde. This substance can cause a fast pulse, sweating and nausea. In most people, the body breaks down acetaldehyde before it causes problems. But it can cause inflammation in organs, leading to uncomfortable symptoms.
If you have alcohol intolerance, you may have a genetic inability to process the acetaldehyde fast enough. You may feel the effects after drinking even a small amount of alcohol.
Effects of factors other than alcohol
- Congeners: These compounds contribute to how alcohol tastes, smells and looks. Researchers think they also contribute to the intoxicating effects of alcohol and a hangover’s severity.
- Using other drugs: Cigarettes, marijuana, cocaine and other drugs also produce intoxicating effects. Using them while consuming alcohol can affect hangover severity.
- Personal differences: Researchers have found that feeling neurotic, angry, defensive or guilty over drinking can increase the hangover risk. If you have a family history of alcohol use disorder or are at high risk of developing it, you may also get more hangovers.
What are symptoms of a hangover?
Symptoms of a hangover include:
- Depression, anxiety or irritability.
- Disturbed sleep.
- Dizziness and vertigo (a sensation of moving when you’re not).
- Fatigue and weakness.
- Headache, red eyes and sensitivity to light and sound.
- Increased pulse and blood pressure; rapid heartbeat.
- Muscle aches and weakness.
- Nausea, vomiting and stomach pain.
- Sweating and thirst.
- Tremor (shaking).
You’re also more likely to have memory, concentration and coordination problems when you have a hangover. In general, the severity of your symptoms depends on how much you drank and for how long. But your health and other factors also play a role. Some people get a hangover after even one drink. Other people who drink heavily don’t get symptoms.
How long does a hangover last?
Typically, your symptoms are the worst when your blood alcohol level returns to zero. Symptoms can last about a day or possibly longer.
Diagnosis and Tests
How are hangovers diagnosed?
Most people who get hangovers can diagnose themselves based on their alcohol consumption and symptoms. If you feel sick after consuming alcohol, you most likely have a hangover.
Management and Treatment
How is a hangover treated?
Many hangover remedies claim to treat a hangover. But they’re often not based in science, and some can be dangerous. For example, drinking more alcohol (“hair of the dog”) will not cure a hangover. More alcohol just increases the toxicity of the alcohol already in your body.
Steps you can take to improve hangover symptoms include:
- Eating bland foods with complex carbohydrates, such as toast or crackers. You’ll boost low blood sugar levels and reduce nausea.
- Drinking water, juice, broth and other nonalcoholic beverages to reduce dehydration.
- Getting sleep to counteract fatigue.
- Taking antacids to help settle your stomach.
- Trying aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, to help your headache or muscle ache. However, use them sparingly since they can upset your digestive system. Do not take acetaminophen (Tylenol®) — it can be toxic to your liver when combined with alcohol.
- Being patient. Hangover symptoms tend to ease up over eight to 24 hours. Your body has to clear the toxic byproducts of alcohol, rehydrate, heal tissue and restore functions and activity to normal.
Can I speed up hangover recovery?
While people may claim that coffee or a shower helps you recover faster, there’s no way to truly speed recovery. The brain and body need time to recover and heal, and there’s no way to fast-track that.
Can I prevent a hangover? (Or reduce its severity?)
If you want to enjoy a drink without unpleasant hangover symptoms, you can try hangover prevention steps:
- Drink less: Symptoms are less likely if you drink small amounts of alcohol. Drink less than the amount it takes to make you feel intoxicated. Even if you do become intoxicated, drinking less can make hangover symptoms less severe.
- Drink slowly: If you’re having carbonated alcoholic beverages such as champagne, drink them slowly. The carbon dioxide bubbles can speed the rate of alcohol absorption in the bloodstream and compete with oxygen absorption.
- Choose wisely: Consume drinks with lower amounts of congeners. Lighter-colored drinks such as vodka, gin, light beer and white wine typically result in less severe hangover symptoms. Darker-colored drinks with high levels of congeners, such as bourbon, scotch, tequila, brandy, dark beers and red wine, cause more severe symptoms.
- Drink water: Alternate alcoholic beverages with plain water. The water helps prevent dehydration.
- Eat: Food helps slow the absorption of alcohol. It’s best to eat before drinking, and a heavier meal can offset alcohol’s effects on your body. Even adding non-diet cola, ginger ale, fruit juice or punch to your drink can help slow absorption.
- Pace yourself: Limit consumption to one drink per hour. That’s about how much your body can process. You’ll help keep your blood alcohol levels from reaching the point of intoxication.
Outlook / Prognosis
Are hangovers dangerous?
Hangovers can cause more than just unpleasant symptoms. With a hangover, you’re not thinking clearly. Alcohol impairs your attention, decision-making processes and muscle coordination. You might engage in risky behavior you wouldn’t ordinarily do. For example, driving during a hangover can be dangerous or even deadly. People can also injure themselves at work.
When does a hangover need emergency care?
Call 911 if you’re with someone who’s been drinking and has any of these signs:
- Breathing that’s slow (fewer than eight breaths a minute) or irregular (if there’s a gap longer than 10 seconds between breaths).
- Cold to the touch (hypothermia).
- Passing out (unconscious) or having trouble staying conscious.
- Severe vomiting.
- Skin that’s pale or blue (in people with dark skin, check the gums, lips and whites of the eyes).
When should I see a healthcare provider?
Hangovers tend to go away on their own, even if you don’t do anything. As the body readjusts to the lack of alcohol, you start to feel better.
However, talk to your provider if you have signs of alcohol use disorder. Your provider can talk to you about options for treatment. Signs include:
- Frequent episodes of heavy drinking.
- Severe alcohol withdrawal symptoms.
- Hangovers and drinking affecting your quality of life, including your relationships and your job.
What else should I ask my healthcare provider?
If you are concerned about hangover symptoms, ask your provider:
- Do I have risk factors for alcohol use disorder?
- Do I have alcohol intolerance or alcohol allergy?
- What can I do to prevent or reduce hangover symptoms?
- How much alcohol is safe for me to drink?
A note from Cleveland Clinic
A hangover is unpleasant, but symptoms tend to go away within a day or so. If you drank too much alcohol and feel sick, try at-home hangover remedies such as drinking plenty of water, eating some carbs and sleeping. There’s no quick cure for hangovers. You need to let your body rid itself of the alcohol and heal. If excessive drinking and hangover symptoms are interfering with your life, talk to your healthcare provider.