What are Hangovers?

The term "hangover" was originally a 19th century expression describing unfinished business — something left over from a meeting — or "survival". In 1904, the meaning "morning after-effect of drinking too much" first surfaced.

A hangover describes the sum of unpleasant physiological effects following heavy consumption of alcoholic beverages. Among the most disturbing treatable effects of a hangover include nausea, sour stomach, headache, vomiting, diarrhea and thirst — all usually felt several hours after cessation of drinking.

Hypoglycemia (low blood sugar) and dehydration are among the most theorized causes of hangover symptoms. If left untreated, these symptoms may persist for several days after alcohol was last consumed.

Hypoglycemia is caused by the impaired ability of the liver to supply glucose (blood sugar) to tissues, especially the brain. Since glucose is the primary energy source of the brain, this lack of glucose contributes to hangover symptoms such as fatigue, weakness, mood disturbances, and decreased attention and concentration.

Dehydration is caused by the osmotic effect of ingested alcohol drawing water out of the tissues into the blood, and directly into the kidneys. This leads to increased urine production (diuresis), otherwise known as "breaking the seal" (ultimately causing dry mouth, lethargy and headaches), as fluids in the brain become depleted.

Dehydration and increased stomach acidity due to alcohol consumption also irritate the nerve signals in the stomach lining, resulting in headache, nausea, heart burn, sour stomach and vomiting.