What causes a hangover?

As your blood alcohol content falls and you start sobering up, you will begin to experience tiredness, nausea, shaking, sweating and a headache. These are the symptoms of a hangover, and they will be at their worst until almost all of the alcohol has been removed from your body.

Hangover severity is directly proportional to the level of intoxication

A hangover is caused by alcohol withdrawal symptoms. A blood alcohol content of just one per mille causes your blood sugar to fall and your body to dry out, which in turn causes a hangover. These symptoms will be at their worst until almost all of the alcohol has been removed from your system.

The severity of your hangover will be directly proportional to your level of intoxication. There will be no connection between the type of alcohol you drank and the severity of your hangover. Read more about intoxication.

Hangover symptoms

The most common hangover symptoms are tiredness, nausea, shaking, sweating and a headache. These symptoms usually appear about 4–12 hours after you either stop drinking or significantly reduce your alcohol consumption. Hangover symptoms are usually strongest 1–2 days after you stop drinking, after which they will gradually reduce in about 4–5 days. The withdrawal symptoms caused by considerable and long-term alcohol consumption may last for weeks after you quit drinking.

Hangover treatments

There is no medication or other way of curing a hangover. How long you will take to recover depends on the severity of your hangover.

Rest is usually the best remedy for hangover symptoms. If you feel up to it, eating and drinking non-alcoholic liquids may help. Having some ‘hair of the dog’ is not a remedy. Consuming more alcohol will remove the unpleasant symptoms by returning you to a state of intoxication and will merely postpone the hangover.

It is a good idea to avoid sport and other strenuous exercise when you have a hangover. Exercise may be life-threatening, particularly to elderly people suffering from coronary and cardiovascular diseases. Even completely healthy people may experience arrhythmia. Read more about the effects of alcohol on sport and exercise.

Article sources:
Duodecim Current Care Guidelines
Finnish Student Health Service

Tips to avoid a hangover
  • Don’t binge drink.
  • Drink alcoholic beverages with food.
  • Choose a low-alcohol or non-alcoholic beverage.
  • Drink water in between. When you drink water in between alcoholic beverages, you will also end up drinking less alcohol. Read more about the benefits of drinking water.