[movies]

So I was out drinking last night and to ensure that I could make it into lab again at the usual time this morning I had a few glasses of water before I went to bed.  Since I'm a big nerd, I tend to think about chemistry a lot when I've had a few drinks and this time I got to thinking about why drinking water would prevent a hangover.  Given some other recent discussions on the forums, I thought someone here might have some input.

Here are my thoughts: It seems unlikely that additional water would have any effect on the oxidation of ethanol to acetaldehyde, which I understand to be the culprit of intoxication.  Also, I can't imagine that drinking water well after drinking alcohol has much of a dilution effect on the alcohol you've ingested (if you were drinking water and alcohol at the same time, I suppose this could have some effect though.)  Finally, I have heard that you need the water to complete the Krebs Cycle, but for that to be true then the ethanol has to have some effect on the Krebs Cycle too because there is always some water in your body.  Anyway, I suppose that if there wasn't a sufficiency of water then you might end up building up a concentration of one of the Krebs intermediates which might then have a toxic effect.

So my ultimate questions are, what are the principle compounds directly responsible for drunkeness, what are the compounds responsible for a hangover the next day, and finally, how does drinking water "fix" the problem?

[Mitch]

You only have one data point. You need to drink the exact same amount tonight without drinking water and let us know how it goes.

[movies]

You only have one data point. You need to drink the exact same amount tonight without drinking water and let us know how it goes.

Ha!

No.

That would not be a good idea.  On Friday however.... :drink:

[Qazzian]

I was under the impression that hangovers was due to dehydration from the alcohol. Mind you, no-one in my family gets hangovers, so I couldn't tell you for sure.

[movies]

Suppose you had 10 beers.  At 355 mL a pop that's a total of 3.55 L of beer.  At about 5% alcohol (by volume), that'd be 0.177 L of ethanol and 3.37 L of water, plus the amount of water that is in your body to begin with (something like 60% of your bodyweight is water, I think).  I can't imagine that small an amount of ethanol would have such a significant effect.

Perhaps I'm wrong though....

[DrCMS]

Ethanol suppresses the formation of ADH (anti diuretic hormone) and even though you are consuming a large volume of liquid your body pisses away even more.  So you become dehydrated and your brain which has a higher water content than the rest of your body is most effected.  Replacing some of that water before you go to sleep reduces the hangover.

[savoy7]

I concur with DrCMS.  Alcohol dilates the blood vessels in ones kidneys and thus more liquid is released as urine.

[Donaldson Tan]

are u all saying that hangover is caused by dehydration?

[DrCMS]

Hangovers are caused by a combination of dehydration, toxic trace impurities in the drink and toxic metabolites.

[jdurg]

That is why drinking a lot of water before going to bed/passing out after a night of drinking is a cure for a hangover.  The water helps flush out the metabolized alcohol, as well as keeping you hydrated.  If your body is fully hydrated then the concentration of the metabolites will be lessened.  You get really nasty hangovers because the brain becomes quite dehydrated which causes the concentration of the 'nasties' to increase tremendously.  This makes you feel horrendous that next morning.