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By Mayo Clinic staffHangovers are caused by drinking too much alcohol.
A single alcoholic drink is enough to trigger a hangover for some people, while others may drink heavily and escape a hangover entirely. In general, however, more than three to five alcoholic drinks for a woman and over five to six for a man will usually result in a hangover. About 75 percent of people who drink to intoxication will have a hangover the next day.
Various factors may contribute to the problem. For example:
- Alcohol stimulates your body to produce more urine. In turn, urinating more than usual can lead to dehydration — often characterized by thirst, dizziness and lightheadedness.
- Alcohol irritates the lining of your stomach, increases the production of stomach acid and delays stomach emptying. Any of these factors can cause abdominal pain, nausea or vomiting.
- Alcohol can cause your blood sugar to fall. If your blood sugar dips too low, you may experience fatigue, weakness, shakiness and mood disturbances.
- Alcohol causes your blood vessels to expand, which can lead to headaches.
- Alcohol can make you sleepy — but your quality of sleep will suffer. This may leave you groggy and fatigued.
- Alcoholic beverages contain ingredients called congeners — which give many types of alcoholic beverages their flavor and which can contribute to hangovers. Congeners are found in larger amounts in dark liquors, such as brandy and whiskey, than in clear liquors, such as vodka and gin.