The margaritas you downed on Friday night leave you slumped in bed all Saturday. On Sunday, you wake up, and you’re still parched and jittery. Your head hasn’t stopped throbbing. Could you be in the throes of a two-day hangover?

In order to metabolise alcohol, the body breaks it down into acetaldehyde, a chemical compound. A hangover can be the byproduct of this process. For a vast majority of people in a vast majority of cases, hangovers follow a predictable pattern: they make you feel weak and weary for about 24 hours and then they abate. But in some cases, the symptoms can last longer.

The more alcohol one drinks, the more likely the hangover is to linger. However, some people are predisposed to hangovers that stretch beyond one day even when they drink a moderate amount, said Emmert Roberts, a psychiatry fellow at Stanford University in the US, who studies hangovers.

Scientists aren’t totally sure why this is, but they are working to untangle it. “There’s been such a dearth of hangover research in general,” Roberts said. Here’s what experts know.

Who has these?

After a big night of drinking, those most prone to feel the after-effects for multiple days fall, paradoxically, into two camps: people who drink heavily quite often, and people who rarely do.

If you routinely consume large quantities of alcohol, you might be familiar with the agony that sets in as your body strains to process it all. This is particularly true if you binge-drink, which the US Centers for Disease Control and Prevention defines as a woman having at least four drinks on one occasion or a man having at least five. However, in some cases, what you consider to be a hangover may actually be the start of serious alcohol withdrawal, said Lara Ray, a professor of clinical psychology at the University of California, Los Angeles, US, who researches alcohol use disorder.

The symptoms of a hangover and alcohol withdrawal can overlap, and it’s important to know the difference, said Dr Anthony March, an addiction medicine specialist at Northwestern Medicine Central DuPage Hospital in the US. If you are vomiting persistently and cannot keep fluids down, having frequent diarrhoea, experiencing confusion or even mild hallucinations, or if your skin is turning blue, you may have a severe form of alcohol withdrawal and you should go to the emergency room as soon as possible.

Conversely, if you don’t drink very often but overindulge one night, one hypothesis for why you may have a longer hangover is that your liver may not be conditioned to produce acetaldehyde, Ray said. That means your hangover symptoms might stick around.

Your age

An older person’s liver may take more time to metabolise alcohol, Ray said. In addition, she said medications such as SSRIs (including Zoloft) can interact with alcohol, potentially leading to more drawn-out hangover symptoms.

As for those unlucky people who suffer from two-day hangovers even after moderate drinking, researchers have a few theories. Some people might be genetically predisposed to more severe hangovers, Roberts said; they may have an abnormally intense reaction to the way booze boosts their blood sugar, which can lead to worse, persistent headaches, or their immune system may struggle to defend against the toll alcohol takes, which can exacerbate and prolong general feelings of sickness.

Other biological factors may contribute as well. “Some people are very sensitive to beer because of yeast; some people are sensitive to different wines because of the sulfites,” March said. “It’s highly individual, and it’s difficult to predict.”

And because “hangover” is such a broad condition (researchers have identified as many as 47 symptoms), something that seems like an alcohol-induced sickness could be another problem entirely.

People may think they are experiencing a long hangover when in fact their symptoms stem from stress or an underlying condition, Roberts said.

How to avoid pain

The obvious guidance is to drink in moderation, since the more drunk you get, the worse your hangover will probably be and the longer it can last. And conventional wisdom on how to ward off a hangover — drinking a glass of water in between alcoholic beverages, eating ahead of time — can help prevent one in the first place.

The type of beverage you drink also matters: tequila, whiskey and darker alcohols contain compounds called congeners, which are more likely to bring on longer-lasting hangovers because of how they are metabolised, Roberts said.

If you consistently experience multi day hangovers because of drinking in excess, it could be a sign of problematic alcohol consumption.

New York Times News Service