Hangover

Definition

Hangover is the collection of physical and mental symptoms that occur after a person drinks excessive amounts of alcohol.

Description

Hangovers have probably been experienced since prehistoric time when alcohol was first discovered. A survey found that about 75% of the persons who drank enough to be intoxicated (drunk) sometimes experienced hangover. Although very prevalent, hangovers have not been extensively studied. It is known that ethanol is the primary chemical component of alcohol to produce the effects associated with drinking.

Whether hangover affects complex mental tasks and the performance of simple tasks is unclear. Studies on these areas have yielded conflicting results, presumably due to differences in methods. Clearly, alcohol consumption can affect sleep, and sleep deprivation is known to affect performance.

Causes & symptoms

The cause of hangover is believed to be multifactorial. Hangover is likely caused by a combination of direct effects of ethanol, effects of ethanol removal, effects of ethanol breakdown products, effects of other components of the alcoholic beverage, personal characteristics, and behaviors associated with alcohol use.

Direct effects of ethanol

Ethanol can directly affect the body by causing dehydration (loss of fluids), electrolyte (body chemicals) imbalance, stomach and intestinal irritation, low blood sugar, and sleep disruption. In addition, alcohol directly affects the circadian rhythm (internal 24-hour clock) causing a feeling similar to jet lag. Ethanol causes vasodilation (enlarged blood vessels) and affects bodily chemicals, like serotonin and histamine, which may contribute to the headache associated with hangover.

Effects of ethanol removal

Because hangover symptoms peak at around the same time that the blood alcohol concentration falls to zero, some researchers propose that hangover is actually a mild form of withdrawal. Excessive drinking causes changes in the chemical messenger system of the brain and, when the alcohol is removed, the system becomes unbalanced. Many of the symptoms of hangover are similar to those associated with mild withdrawal. Some differences exist, however, between hangover and withdrawal; specifically, hangover symptoms do not include the hallucinations, seizures, and the lengthy impairment of withdrawal.

Effects of ethanol breakdown products

In the body, ethanol is first broken down to acetaldehyde and then to acetate. Acetaldehyde is a reactive chemical that, at high concentrations, can cause sweating, rapid pulse, skin flushing, nausea, and vomiting. Some researchers believe that acetaldehyde causes hangover. Although there is no acetaldehyde in the blood when the blood alcohol concentration reaches zero, the toxic effects of acetaldehyde on the body may still persist.


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