Binge drinking, or downing an excessive amount of alcohol in a short time, is definitely one way to almost guarantee a hangover the next day. However, you certainly don't have to be a binge drinker to experience one. In fact, some people can get a hangover after just one little drink. How is this possible?
Whether you'll have a hangover after drinking depends on numerous factors, including your body size and sex. The average man will have some kind of hangover after knocking back five to eight drinks, while a woman will only have to down three to five for the same effect [source: Johns Hopkins Medicine]. In addition, your ethnicity can play a factor in how prone you are to a hangover. The Japanese, for example, tend to develop hangovers after fewer drinks because their bodies are genetically less able to break down acetaldehyde, alcohol's main byproduct. Suffer from migraines? Then you're probably more prone to hangovers, too, as are those who are taking certain medications that affect liver enzymes. Ironically, those who drink liquor regularly often are less likely to become drunk or to suffer a hangover the next morning [sources: Hudepohl, Johns Hopkins Medicine].