Hangovers - Symptoms and Causes

What Happens During a Hangover

A hangover refers to a set of uncomfortable symptoms that follow excessive alcohol consumption. These symptoms can range from mild to severe. They often include headaches, nausea, fatigue, and sensitivity to light and sound.

Drinking large amounts of alcohol increases your chances of experiencing a hangover the next day. Unfortunately, there’s no reliable formula to determine exactly how much alcohol will cause a hangover for any specific person.

Most hangovers resolve without treatment, though they may last up to 24 hours. During this time, many people experience decreased productivity and increased tension in their relationships at home, work, or school.

Making responsible choices about alcohol consumption remains the most effective way to prevent hangovers. This includes knowing your limits and not exceeding them when drinking.

Signs of a Hangover

A hangover starts when your blood alcohol level drops to near zero. These effects are usually strongest the morning after drinking too much. Based on what kind of alcohol you drank and how much, you might experience:

Extreme fatigue and weakness
Thirst and dry mouth
Headaches and muscle pain
Stomach discomfort, nausea or vomiting
Poor quality or insufficient sleep
Sensitivity to light and sound
Dizziness or vertigo
Trembling and sweating
Difficulty thinking clearly
Mood changes like sadness, worry or irritability
Rapid heartbeat

When to Talk to a Healthcare Provider

Hangovers from a single night of drinking normally go away on their own. If you’re worried that you drink heavily often and this might lead to serious health issues like alcohol withdrawal, speak with your doctor.

Emergency Warning Signs

Sometimes heavy drinking causes more dangerous symptoms that signal alcohol poisoning—a potentially fatal emergency. Drinking large amounts of alcohol quickly can affect your breathing, heart rate, body temperature, and gag reflex, sometimes leading to coma or death.

Call 911 immediately if someone who has been drinking shows these signs:

Confusion
Vomiting
Seizures
Slow breathing (fewer than 8 breaths per minute)
Irregular breathing patterns with long pauses
Clammy or sweaty skin
Bluish or grayish skin tone
Slow heart rate
Low body temperature
Trouble staying conscious
Passing out and being unable to wake up

A person who cannot be awakened is at serious risk of dying. Even if you don’t see all these symptoms, get medical help right away if you suspect alcohol poisoning.

Why Hangovers Happen

Drinking too much alcohol causes hangovers. Some people get hangovers after just one drink, while others can drink heavily without feeling bad the next day.

Alcohol makes you urinate more often, which can lead to dehydration. When you’re dehydrated, you might feel thirsty, tired, and dizzy. You might also have a headache.

Your immune system responds to alcohol with inflammation. This can make you feel sick, with symptoms like trouble thinking clearly, poor memory, and loss of interest in activities.

Alcohol irritates your stomach lining and increases stomach acid. This can cause stomach pain, nausea, and vomiting.

When you drink, your blood sugar levels can drop too low. This can make you feel weak, shaky, and tired. It might even change your mood or cause seizures in severe cases.

Alcohol disrupts your sleep quality. Even if you fall asleep quickly, alcohol prevents restful sleep. You might wake up during the night or too early in the morning, leaving you tired and groggy.

Congeners

What are congeners? These are ingredients in alcoholic drinks that give them their distinct taste and smell. They also play a significant role in causing hangovers.

Dark liquors contain more congeners than clear liquors:

Liquor Type	Congener Level	Examples
Dark liquors	High	Brandy, bourbon, whiskey
Clear liquors	Low	Vodka, gin

Drinks with more congeners are more likely to cause hangovers or make them worse. However, drinking too much of any alcoholic beverage—even those with fewer congeners—can still result in a hangover.

Your body needs time to process alcohol and its byproducts. The more you drink, the longer this takes, and the worse your hangover might be the next day.

Risk Factors

Hangovers can affect anyone who drinks alcohol. However, certain factors may increase your chance of getting a hangover or make symptoms worse.

Your genes play a role in how your body processes alcohol. Some people have a genetic variation that causes flushing, sweating, or feeling sick after drinking even small amounts.

Several factors can make hangovers more likely:

Drinking without eating first – When your stomach is empty, alcohol enters your bloodstream faster.
Combining alcohol with other substances – Using nicotine while drinking increases hangover risk.
Poor sleep after drinking – Alcohol disrupts normal sleep patterns, leading to poor-quality rest.
Family history – If close relatives have alcohol problems, you might process alcohol differently.
Choosing dark drinks – Beverages like red wine, dark rum, and whiskey—contain higher levels of congeners (natural compounds formed during fermentation) that may worsen hangover symptoms.

Wine Headache

Some people experience headaches within hours of drinking wine, particularly red wine. This reaction differs from a typical hangover and may occur even after consuming small amounts.

The exact cause remains unclear, but researchers believe certain compounds in wine might trigger these headaches. Possible culprits include:

Tannins (natural compounds that give wine its bitter taste)
Histamines (which can cause inflammation)
Sulfites (preservatives added to wine)

People who get wine headaches may have a sensitivity to these substances. The headache typically develops faster than a hangover headache and may occur without other hangover symptoms.

Scientists continue to study this phenomenon to better understand why some people are more susceptible than others.

Complications

Hangovers can lead to several problems with your thinking skills. You may find it hard to think clearly, remember things, or pay attention to tasks. Your coordination might also be affected.

These temporary issues can cause problems in your daily life:

Tardiness or absence at school or work
Difficulty completing tasks
Conflicts with other people
Falling asleep during important activities
Unsafe operation of vehicles or machinery
Injuries in the workplace

Your ability to function normally is reduced during a hangover. This can affect your performance and safety in many situations. The impact can be felt at home, school, or work environments.

Prevention

Preventing a hangover is much easier than treating one. There’s only one sure way to avoid a hangover – don’t drink alcohol.

For those who choose to drink, moderation is key. Healthy adults should follow these guidelines:

Women: No more than one drink daily.
Men: No more than two drinks daily.

The risk of a hangover increases with the amount of alcohol consumed. Here are practical strategies to reduce your chances of waking up with hangover symptoms:

Eat before and during drinking sessions. An empty stomach allows alcohol to enter your bloodstream more quickly. Having food in your system can slow this process.
Be selective about your drinks. Beverages with fewer congeners may cause less severe hangovers. However, all alcoholic drinks can lead to hangovers regardless of type.
Stay hydrated. Drink a full glass of water between alcoholic beverages. This helps maintain hydration and naturally slows your alcohol consumption.
Set limits and stick to them. Before going out, decide how many drinks you’ll have and don’t exceed that number. Don’t let social pressure influence your decision.
Pace yourself properly. Limit yourself to one alcoholic drink per hour, and stop when you’ve reached your predetermined limit.

Some people take pain relievers preventatively, but this approach requires caution. Consult with a healthcare provider about potential risks. Aspirin and ibuprofen can increase stomach acid production, while acetaminophen combined with alcohol may cause serious liver damage.