'Hangover' is a blanket term for the various after-effects of excessive alcohol consumption. The chief symptom of a hangover is a crippling headache, and an inability to concentrate. Other symptoms include nausea, shaking, weakness, and lack of coordination. A hangover is caused by a combination of many factors, including dehydration, methanol poisoning, salt loss, sugar loss, and vitamin and mineral deficiencies. The most important factors are dehydration and methanol poisoning, as they are the main causes of the headache. All other symptoms are merely annoying, not incapacitating.
Certain drinks are (relatively) high in methanol, which your liver breaks down into various toxins, including formaldehyde. These toxins can cause headache and nausea. The liver processes ethanol in preference to methanol, so consuming further ethanol will halt the methanol breakdown, postponing it until the the ethanol is used up again. This can lower the peak concentration of methanol-related toxins, resulting in a hangover that is longer, but less severe. In general, the clearer the drink, the less methanol -
whiskey, red wine, brown tequila, brandy, etc. contain more methanol than white wine and beer, which contains more methanol than vodka, gin, etc.
Ethanol is a diuretic; it interferes with the re-absorbsion of water by the kidneys, causing the body to become dehydrated. Dehydration causes the internal organs to contract. When the brain contracts, it pulls away from the inside of the skull, irritating the dura (the membrane surrounding the brain), which causes the headache. The psycological effects of alcohol (reduced sense of pain, impaired judgement) make this dehydration less obvious than normal. During the night, the anaesthetic effects of the alcohol may wear off, which can cause the headache to become perceptable, reducing the quality of sleep, or even causing one to awaken. Sleeping poorly can contribute to the secondary symptoms of a hangover. Painkillers may help in improving the quality of sleep, and may still be effective by morning, reducing the perception of the headache. Certain painkillers may react adversely with alcohol - it would be wise to read all the information that comes with your painkillers, preferably before you consume alcohol.
The liver disposes of around one unit of alcohol per hour. It is entirely possible to wake up after a drinking binge, and still be intoxicated (For example, the alcohol from only four pints of lager could take ten hours to completely metabolise). This can contribute to the feelings of nausea, and will also reduce coordination. If you think that there is a chance you may still be drunk, please do not attempt to drive.
Secondary symptoms may also be influenced by a loss of vitamins, salts and sugars. The increased rate of urination and the effects of alcohol on the liver can lead to a loss of sugars and salts, which can cause weakness, nausea, and shaking. Isotonic sports drinks, and 'hangover powders' can help replace these lost sugars and salts. Breaking down alcohol can result in an increased need for vitamin B1 - over-the-counter supplements, or foods rich in B vitamins (such as fortified breakfast cereals, eggs and meat) provide vitamin B1, which may reduce hangover symptoms.
While there is not much that can be done the night before about the methanol, save from not drinking it in the first place, dehydration is easy to cure. Any isotonic or hypertonic liquid that does not contain a diuretic (such as caffeine) will act to rehydrate the body. Water is probably best, being hypertonic, cheap, and having no caffeine. Drink far more water than you think you need. A good rule-of-thumb is to attempt to drink as much water before bed as beer you consumed previously (250ml of water per unit of alcohol). Fill up a resealable bottle with water, and leave it by your bed in case you wake up in the night. The sealed bottle prevents it from spilling when you knock it over fumbling for it.
The following steps should be sufficient to avoid the headache. The secondary symptoms of a hangover are many and differ from person to person, as do their remedies.
- If you are susceptable, avoid drinks high in methanol
- Drink lots of water, far more than you feel you need
- Take a bottle of water to bed with you
Ned Rozell "Anatomy of the New Year's Hangover" Alaska Science Forum
December 23, 1998. September 11, 2003
"Hangovers Are No Holiday"
07 February 1999. September 11, 2003
"Hangover Cures" H2G2
16th November 2000. September 11, 2003