Opinion: as Dry January ends, some advice and myth-busting about how best to avoid hangovers

For something that happens to so many people so often, the clinical understanding of the hangover is quite limited. The symptoms are well-known: a dark constellation of unpleasantness and misery including fatigue, headache, increased sensitivity to light and sound, redness of the eyes, muscle aches, thirst, nausea, vomiting, dizziness, and sometimes depression, anxiety and irritability. Quite the cocktail.

The root of some of these symptoms is clear enough. For example, alcohol promotes the production of urine, thus causing dehydration and thirst. Alcohol also directly irritates the lining of the stomach, causing nausea and vomiting. On a stranger note, alcohol disrupts our circadian rhythm, the "inner clock" of our body which carries out activities depending on the time of the day; as a consequence of this, having a hangover can be similar to suffering from jetlag and vice-versa.

"The hangover is clearly dependent on how much and how fast you drink"

The strangest thing of all is that research has not been able to pinpoint whether hangovers are caused by direct effects of alcohol or by its withdrawal. After all, hangover symptoms begin hours after drinking, when the alcohol concentration in the blood is falling, and peak when it reaches zero. Also, hangover symptoms are a milder version of those experienced by alcohol withdrawal in heavy drinkers. Hence the "hair of the dog" cure (which is really not a good idea at all, in case you were wondering).

The hangover is clearly dependent on how much and how fast you drink. It is generally considered that a healthy adult body can eliminate one standard drink (equivalent to about 10 grams of alcohol) per hour, although this depends heavily on size, sex, muscle/fat ratio, metabolism, previous exposure to alcohol and genetic makeup.

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In general, we can say that spirits – which have higher alcohol content in smaller volumes and therefore get absorbed quicker – are responsible for worse hangovers than beer or wine. Carbonated alcoholic drinks are also absorbed faster in most people. This is true of carbonated drinks like champagne (it doesn’t go to your head so much as straight into your bloodstream) but also of spirits with a carbonated mixer. Beware of the innocent tonic in your gin!

Drinking on an empty stomach also causes alcohol to be absorbed quicker, as a full stomach will take longer to empty into the intestines where most of the alcohol is absorbed. Once the alcohol has been absorbed, however, food will make no difference to your hangover (or drunkenness).

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Some studies have shown that the amount of alcohol consumed does not always go hand in hand with the severity of the hangover. This could be because of congeners, chemical compounds present in alcoholic drinks that give flavour, colour and smell. Tannins in wine are a classic example of congeners. Clear beverages such as vodka have very small quantities of congeners, while beverages such as bourbon, red wine and rum contain significant amounts.

A small study carried out with university students (who were paid for this, if you can believe it) showed that drinking bourbon and cola resulted in worse self-reported hangovers than drinking vodka and cola. In spite of the students assessing their bourbon hangovers as worse, their performance in skills tests was the same after drinking either beverage. Researchers currently agree that although there may be a small worsening effect of congeners in hangovers, the total amount of alcohol ingested is the main issue.

Having different types of drinks makes it easier to lose track of how much you have been drinking so people who mix usually end up drinking more

What about mixing drinks? Popular wisdom claims that mixing drinks will result in a hangover of nuclear proportions, whereas if you stick to the one drink type you’ll be fine(ish). But is there evidence for this? In broad terms, no. Although it is true that people who mix drinks have worse hangovers overall than those who don’t, this is likely not caused by the mix itself. Having different types of drinks makes it easier to lose track of how much you have been drinking, particularly when shots are involved, so people who mix usually end up drinking more.

However, a mix that turns out to be quite nuclear indeed is that of alcohol and energy drinks. The caffeine in these drinks is a stimulant, which decreases perception of drunkenness in drinkers. They are still getting drunk, but they consider their heads to be clearer than they really are because of the stimulating effect of the caffeine. As a result, people who mix alcohol and energy drinks end up not only drinking more overall – and therefore having worse hangovers – but are also more likely to be involved in general shenanigans and more serious events such as fights and car accidents.

"Unfortunately, medicine has not yet found the miracle cure that will rid humanity of all hangover symptoms"

So what to do if you’re already there? Unfortunately, medicine has not yet found the miracle cure that will rid humanity of all hangover symptoms. However, some interventions have shown promise, particularly in reducing tiredness, stomach ache, nausea and vomiting.

These are polysaccharide rich extract of Siberian ginseng, red ginseng drink, Korean pear juice, KSS formula (a Chinese folk remedy containing tangerine pith, ginger, brown sugar and dextrin), and After‐Effect (a mixture of borage oil, fish oil, vitamins B1, B6, and C, magnesium, milk thistle and prickly pear extract). Not quite the stuff you find in your local supermarket. Nevertheless, these results need to be confirmed in larger studies (as they were all carried out in small numbers of volunteers) and also to be carried out in women (as all of the volunteers were men, and women are known to get hangovers too).

READ: the science of a hangover

Of course, the most effective way of avoiding a hangover is not drinking too much to begin with, but you know that already. If you’re putting an end to your dry spell, be sure to have a big dinner beforehand, stay away from energy drinks and enjoy responsibly.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ