If you were out partying last night, you're probably feeling at least a little rough today. Perhaps your head is throbbing, your mouth is dry, and you are craving salt and sugar but aren't certain you can stomach any food. Even worse, if you have to get any work done, your mind is foggy and it's hard to focus. We get it. But what is it about veisalgia — the medical term for a hangover, derived from kveis, a Norwegian word that means "uneasiness following debauchery" and -algia, a Greek root that means "pain" — that leaves you feeling that way? Just a note: We're looking at hangover symptoms specifically here, not the effects of long term alcohol abuse or alcoholism, though frequent hangovers are a sign that you could have a drinking problem. Linette Lopez contributed to an earlier version of this article. A major component of hangovers has to do with the way our bodies break down alcohol. Researchers still don't know exactly what causes a hangover, but the way we metabolize alcohol is at least partly responsible, according to Richard Stephens, a psychology professor and member of the Alcohol Hangover Research Group, an organization that's trying to answer questions in what they call the "neglected issue" of hangover studies. Stephens told The Atlantic that one thing researchers know that our body first metabolizes ethanol, the main alcohol in booze. But after we break that down we start to break down other alcohols, including methanol, which our body turns into formaldehyde and formic acid — toxins that make you hurt. This process happens about 10 hours after we stop drinking. There's a biological basis for the idea that "hair of the dog" helps — but that also explains why hangovers are a risk factor for alcoholism. If someone has a drink the next morning, their body will soon realize that there's more ethanol in their bodies to start breaking down. Since our bodies prefer ethanol, they'll stop breaking down methanol into those toxins at this point, which is why a bit of the "hair of the dog that bit you" can at least temporarily take the pain and sick feeling of a hangover away. Stephens says that researchers think this is why hangovers may be a risk factor for alcoholism instead of a natural deterrent to becoming an alcoholic. Studies show that alcoholics get some of the most severe hangovers around. Hangovers actually get less severe as you get older. This may seem impossible — lots of people recall being able to party AND study back when they were in college. But a study in the journal Alcoholism of 51,645 Danish men and women found that the older someone gets, the less likely they are to experience a severe hangover after a binge drinking session — even after controlling for food consumption and quantity and frequency of regular drinking. Our bet? You might just physically feel worse in general if you are older and less fit than you once were. Plus, you might have more responsibilities that force you to get off the couch. See the rest of the story at Business Insider