alcohol hangover

Credit: Pixabay.

Science knows surprisingly little about what causes hangovers or how we can tackle them. While there are thousands of studies dealing with alcohol one way or the other, there are only a handful of published scientific papers that explore what causes hangovers and whether or not there’s a cure. That’s quite a shame too, considering hangovers are the bane of every weekend warrior all over the world.

What physiological changes or biological interactions with alcohol could be responsible for the diabolical melange of headache, nausea, poor appetite or diarrhea, to name a few? According to the Alcohol Hangover Research Group (AHRG), “an international expert group” which aims to “elucidate the pathology, treatment, and prevention of the alcohol hangover,” most of what we know about the morning-after effects of heavy drinking is wrong.

What causes hangovers?

According to the AHRG, “alcohol hangover develops when blood alcohol concentration (BAC) returns to zero, and is characterized by a feeling of general misery that may last more than 24 h.” 

In a 2008 article published in the journal Alcohol & Alcoholism, Dutch researcher Joris Verster dispels a number of popular beliefs surrounding the triggers for alcohol hangover symptoms.

One of the most widely cited reasons why people feel wretched following heavy drinking is dehydration. Alcohol is known to suppress a hormone called vasopressin, which typically keeps you from feeling the need to urinate. Because you urinate more often, the body also loses more water. What’s more, if you’re drinking whiskey or other spirits, water is likely not on the menu for the rest of the evening, which worsens the dehydration. Why is it then that even if you neck copious amounts of water before you go to bed or while drinking alcohol, there will still be a dreadful hangover the next morning? That’s because dehydration doesn’t have much to do with it, says Verster.

Research suggests that levels of electrolytes — naturally occurring elements and compounds in the body that conduct electricity when dissolved in water — are more or less the same in both controls and people with hangovers. Even in those cases where there were some differences in electrolyte levels, these didn’t correlate with the severity of hangover symptoms. What’s more, studies haven’t been able to link hormones associated with dehydration and hangover severity.

According to Verster “alcohol hangover and dehydration are two independent yet co-occurring processes that have different underlying mechanisms.” In other words, drinking alcohol will dehydrate causing symptoms such as dry mouth and thirst. Drinking alcohol will lead to a hangover but not because you’re dehydrated. 

To be fair, there’s one major hangover symptom that can be attributed, or at least largely so, to dehydration: the annoying monster headache. Blood vessels narrow because of dehydration, restricting the flow of blood and oxygen to the brain in the process. In an attempt to restore fluid levels, blood vessels begin to dilate causing swelling around the brain.

The nausea we feel the morning after can be explained by alcohol’s effects on the stomach and intestines, which become irritated, causing inflammation. Alcohol also triggers the production of extra gastric acid along with more pancreatic and intestinal secretion.

Acetaldehyde, a byproduct that builds up in response to alcohol processing in the body, is thought to be 30 times more toxic than alcohol itself. Studies have shown that it produces hangover symptoms. The substance may partly explain the origin of hangovers.

Another intriguing hypothesis that might explain the origin of hangovers suggests that alcohol affects the immune system. Previously, researchers found a strong correlation between high levels of cytokines, which are the immune system signaling molecules, and hangover symptoms. When the body gets infected, cytokines trigger fever or inflammation, but it seems that excessively drinking alcohol can trigger a similar response, causing symptoms like muscle aches or headache, but also cognitive effects like memory loss and irritation.

Why hangovers are worse for some people

Some people seem more prone to hangovers. One study found that age may play a big part in hangovers, with adolescent drinkers reporting the symptoms of alcohol withdrawal less frequently than older adults. Another study found adolescent rats are less sensitive to the effects of a hangover has on anxiety and sociability.  The jury isn’t out yet as a recent Danish study which examined younger and older adult drinkers and found that the tendency to experience hangovers after binge drinking actually decreased with age.

Women seem to report the worst hangover effects, but that may be due to lower body weight than men rather than some intrinsic female biology. A total of 12.6 percent of women surveyed in the study say they ‘almost always’ or ‘always’ have a hangover after having more than five drinks at a party. The figure for men is 6.1 percent.

Are some types of alcohol more likely to give you a hangover?

Credit: Verster et al.=

Credit: Verster et al

You might have heard friends say that some types of alcohol give you a worse hangover or you might have experienced the feeling yourself. Like a lot of things related to hangovers, this hypothesis is rather poorly studied, but one important review from the 1970s seems to suggest there’s some truth to the idea. According to the study, alcoholic drinks with congeners — substances produced during the alcohol fermentation process or added later in the production — may enhance the toxicity effect of alcohol and, hence, increase the likelihood of a hangover.

Specifically, it seems like gin and vodka, both drinks with fewer congeners, are less likely to introduce a hangover episode than drinks with higher levels of congeners like brandy or red wine. Another study which followed 95 heavy drinkers compared vodka versus bourbon and reached similar results. 

So what can you do to cure a hangover?

There are a couple of things you can do to make things easier for you the next morning.

  • Don’t drink too much alcohol in the first place… but if that’s not an option,
  • At least don’t drink quickly or on an empty stomach.
  • Food doesn’t absorb the alcohol but a full digestive tract will slow down alcohol’s absorption into the bloodstream. Eating also replenishes electrolytes.
  • As we’ve learned, dehydration doesn’t really cause a hangover but it is partly responsible for some symptoms. Drinking a glass of water for every alcoholic beverage could prevent a very serious headache.

If you arrived here by googling a ‘science-based cure for hangover’, I’m sorry to break it to you but there’s no such thing yet. You’ll find many urban legends and anecdotal cures for hangovers — from coffee, eggs Benedict, tripe soup, and all the way to shrimp — but there’s no study that suggests any of these works. What you can do, however, is attack some of the symptoms. Aspirin or ibuprofen (Advil) can treat headaches and muscle pain while drugs like Tums or Pepto-Bismol can reduce nausea.

Until science comes up with a cure for hangovers, it’s best you wait it out.

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