Can You Really Sweat Out a Hangover?

man standing over treadmill — Exercising after drinking won't do a thing to shorten your hangover. And it can leave you even more dehydrated. Image Source/Getty Images

A hangover is the body's way of saying "I hate you." The spinning nausea. The pounding headache. The, er, "stomach issues." We hope last night was a blast, because today is going to suck.

Ever since the first overzealous Mesopotamian guzzled too much fermented barley meal, there have been hangovers. And for nearly as long, there have been scientifically questionable hangover preventions and "cures." Among the favorites, eating a bunch of greasy food to soak up the alcohol and settle your stomach. Drinking only beer or liquor on the same night, but never both. And of course the classic "hair of the dog," waking up to a shot of the stuff that nearly killed you.

You might even have a drinking buddy who jogs home from the bars every Friday night and swears that working up a good sweat is the best way to leach out the toxins that cause a hangover. Not only is your friend absolutely wrong, but he could be putting himself at risk of serious dehydration.

First, the source of the confusion. Like all good hangover myths, the "sweat it out" cure contains a grain of truth. The body flushes alcohol out of its system in two ways. The first is through urine, breath and sweat. So it would stand to reason that if you sweat more, the more alcohol you will flush out and faster.

But this conclusion completely ignores the second way that the body gets rid of alcohol, which is through a process called oxidation in the liver. Scientists believe that more than 90 percent of alcohol is oxidized by the liver and less than 10 percent is flushed out through water loss via urine, breath and sweat.

So even if it's technically true that you can sweat out a sip of your gin and tonic, it amounts to a very small sip. So that's strike one against the sweat cure. Strike two is that alcohol itself is not what causes many of the symptoms of a hangover. For that, we have to go back to our old friend the liver.

The oxidation of alcohol in the liver is a chemical process by which molecules of ethanol are first broken down and converted into acetic acid and ultimately into harmless carbon dioxide and water. But within that beneficial process is a nasty intermediate stage. When ethanol is first broken down, it's converted into an organic compound called acetaldehyde that's straight up toxic to the body.

If you drink slowly and in moderation, the liver can process the equivalent of one drink (0.5 ounces of alcohol) an hour without building up toxic levels of acetaldehyde in the blood. But if you drink too much alcohol too quickly, the concentration of toxic acetaldehyde in your system will trigger a number of unpleasant symptoms, including sweating, flushing of the facial skin, headaches, dry mouth and nausea.

What Happens to Your Body During a Hangover

A hangover is the pitiable result of the body not having time to metabolize all of the alcohol quickly enough. Long gone is the pleasant buzz of drunkenness and all that's left is the bitter poison. And since more than 90 percent of alcohol is processed in the liver, the tiny bit that leaves the body through sweat, even lots of sweat, wouldn't significantly reduce overall acetaldehyde levels.

But here's the truly dangerous part of running home from the bar in a rubber tracksuit like Matthew Modine in "Vision Quest." Alcohol is a natural diuretic, prompting the kidneys to produce more urine, which explains why you go to the bathroom a lot more when you drink beer than when you drink Shirley Temples.

Not only do you pee more when you drink alcohol, but your body temperature rises, causing you to naturally sweat more. After a serious night of drinking, your body lose a lot of fluids, which leads to dehydration. Dehydration, in fact, is the root cause of many of the classic hangover symptoms like dry mouth, headaches and lethargy.

Imagine how much more dehydrated you'd be, and how much worse you'd feel, if you went for a sweaty jog after all those Jagermeister shots. Severe dehydration can even lead to coma, organ failure and death. Not to mention running around drunk and dehydrated could lead to a nasty fall.

If you really want to prevent a hangover, do the opposite of sweating it out. Make sure to stay well-hydrated by alternating alcoholic beverages with a glass of water. Not only will you stay hydrated, but the intervening glass of H₂O will give your body time to naturally process the alcohol before the next cocktail.