Is there a physiological reason for a blackout. Or for a hangover?

any ideas
Answer:
Yes for both... since you're asking about a hangover, I assume you mean a blackout from drinking, and not a non-alcoholic blackout.

A hangover is a syndrome, meaning there are several reasons for the feelings you experience. First you're dehydrated due to the alcohol, second if you started drinking at 6-8pm and continued until 2-3am you haven't eaten anything in a while and your body is still awake, so you're starting to switch into the early stages of starvation, and you begin burning your liver and muscle glycogen stores...but wait! Your liver can't do that because it's too busy detoxing the alcohol, so instead you start breaking down muscle and stored fats. Also since your liver is breaking down the alcohol it can't completely keep up with producing the other cofactors needed for reactions throughout the body. Alcohol also causes the smooth muscle around your blood vessels to relax, which causes bloodshot eyes, as well as that pounding headache. These symptoms along with the fact that alcohol is a gastrointestinal irritant, gives you the nausea you might feel.

So for ideal hangover prevention (not a guarantee by any means) eat something before you go to bed, preferably something semi-healthy rather than fast food. Drink at least two full glasses of water, take two anti-inflammatories (ibuprofen) and maybe a pepto also. 8 hours of sleep, and drinking water throughout the night of drinking will also help reduce the hangover possibility.

As far as a blackout goes, its a little more complex, and still a bit unknown. The biggest question is the recurrence of blackouts, meaning if you have a blackout from drinking once, the fact that it happens easier the next time, and may happen everytime when drinking heavily.

In general an alcoholic blackout is mainly due to the alcohol and its effect on the brain, depressing reactions, and slowing normal processes. Alcohol affects the cerebrum first, which is where your general knowledge is stored, and generally works its effects downward to the cerebrum (balance and word slurring) and then to the brainstem (problems breathing and death). Its the drinking that is enough to affect the cerebrum when blackouts mainly occur, because you've now affected beyond where memories are integrated and stored into long term from short term memory...this line is kind of hazy too, explaining why you might not remember a funny event from last night's drinking episode until someone reminds you of what happened, and it becomes clear again.

So to sum it up, alcohol is a systemic drug, and has different physiological effects on every part of the body because it is seen by the body as a toxin, so your body wants to get rid of it as soon as possible, and it leaves other normal processes by the wayside while trying to eliminate the immediate toxic threat.

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usually people black out when oxygen is cut off (or lowered)to the brain.

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