The hangover can have the following symptoms: dryness in a mouth, headache, tremor (a shiver in all body), irritability, reddening of eyes, hypersensibility to light and noise, nausea, vomiting, melalgia, appetite and sleep loss, a depression, diarrhea. The following conditions are possible: full apathy and so-called “adrenalinic melancholy” — sense of guilt, feeling that the day before made something improper, wrong, even having a distinct memory on occurring events and accurate understanding of that fact that no really shameful actions existed.
Ethanol causes increased formation of urine (raised diuresis) that leads to origin of headaches, dryness in a mouth and to feeling of fatigue, prostration, dehydration.
Other factor causing a hangover is formation of products of decay of ethanol in a liver:
Ethanol => acetic aldehyde => Acetic acid
In a liver there is an intercurrent transformation (oxidation) of ethyl alcohol in acetic aldehyde by means of enzyme , and then there is a transformation acetic aldehyde to acetic acid by means of enzyme acetic aldehyde dehydrogenase. In case of excess of alcohol in blood fermental systems doesn't cope with complete transformation of acetic aldehyde in acetic acid, the intercurrent product аcetic aldehyde — more toxic, than alcohol as a result is collected. Acetic aldehyde (ethanal) is 10 — 30 times more toxic than alcohol. Besides, alcohol causes formation of the CYP2E1 enzyme, which itself can form toxins and free radicals.
For mentioned above two reactions of oxidation of ethanol NAD+transformation (Nicotinamide adenine dinucleotide) in NADH (got into condition NAD +). In case of excess of NADH framing of three enzymes of a cycle of tribasic carboxylic acid (citrate synthesis, isocitrate dehydrogenase and complex oxoglutarate dehydrogenase) is broken up to their complete lock. Pyruvate (the final product of glycolysis) starts to collect and excess of NADH forces lactic dehydrogenase to synthesize a lactate from pyruvate to fill NAD + and to support life. Thus, pyruvate is excepted from other processes, such as gluconeogenesis that deprives a liver of possibility to compensate falling of level of glucose, especially in a brain. As glucose — is the principal power source for a brain, the originating shortcoming glucose (hypoglycemia) promotes such symptoms of a hangover, as fatigue, weakness, the mood violation, the under attention and concentration.
Also it is considered that presence of other substances (such as fusel oils), appearing together with ethyl alcohol in the course of fermentation, considerably strengthens many symptoms of a hangover. In hard alcohol drinks also add zinc and other metals for a drink sweetening. These facts explain the relative softness of a hangover in case of the use of the distilled alcohol, for example, vodka. In research of 2009 certificates that a hard liquor of more dark painting, such as bourbon, cause heavier hangover, than light were received. The content of tannin in drink also matters. Sugar also aggravates effect therefore behind sweet cocktails the reputation of the drinks leading to a heavy hangover was set. Dark beer or strong Stout lead to a stronger hangover, than similar quantity on volume of the alcohol dissolved in water. Whisky, tequila lead to heavier hangover, than vodka, in case of the use in equal (in terms of pure ethanol) quantities. The reason that fusel oils and other accompanying substances aren't deleted from these drinks for taste and flavor formation.
It is necessary to note that the hangover from the use of the beer, which in itself provokes diuretic effect, causes aspiration of the person to visit a toilet more often, and to get rid not only of the used beer, but also from remaining liquid of an organism. Alcohol causes diuretic effect, causes irritations of a hypophysis of a brain and pauses separation of watery substance which influences kidneys in a special way so that they reduce outflow of water which shall accumulate in a bladder. As a result at first beer provokes excessive separation of liquid from an organism, and then in case of accumulation of sufficient concentration of alcohol in blood breaks a natural urinary flow that causes dryness appearance. For the purpose of liquid compensating, the organism absorbs water from other organs and tissues including from a brain, causing its temporal abbreviation. Researchers consider that despite own immunity of a brain to pain, it is supposed that the outer solid brain tunic is reduced also. And it is in turn already connected to fibers which can feel pain – thus strong headaches can be explained. The strong headache is provoked by also large amount of used beer, and as a result its strongest impact on vessels because of what the normal blood circulation in the head is affected. And alcohol keeping in a stomach for a long time causes its irritation and the subsequent sick. Thus the beer hangover except the strong headache, nausea, differs by the increased dryness in a mouth and thirst. The reason is that beer being a much less strong drink than vodka is drunk in much bigger doses.
Poisoning with fusel oils and other by-products of distillation of the alcohol can considerably strengthen symptoms accompanying hangover, they are often available as a part of self-made (moonshine, home brew), and also forged of crude technical alcohol, cheap and of bad quality alcohol drinks.
Poisoning with nicotine can strengthen also the severity of a hangover as under the influence of alcohol smokers smoke more often than normally (and also occasionally those smoke who don't smoke in a sober status).
Medical researches enable to define the significant role of a deficit of magnesium in development of a hangover syndrome. In total in a few minutes after coming of alcohol in an organism magnesium is removed through kidneys and gets to a bladder. Magnesium ceases to lock calcic channels in cells, and calcium easily penetrates in cells, causing their excessive excitation. From here the person has a nervousness and irritability status and there is a headache. The magnesium deficit causes also muscular weakness, warm arrhythmia and a fever. Besides, in case of consuming of a large amount of alcohol there is an acidity increase in blood (acidosis).
Genetic predisposition also matters: so, some people cannot almost suffer from a hangover syndrome, irrespective of quantity drunk, or rarely suffer from it: it is genetically explained by the ability to work out alcohol dehydrogenase at the different peoples. It is worse at white-skinned light-eyed Europeans and it is better at black, dark-haired, dark-eyed peoples.
The majority of people of the East Asian origin possess a mutation in a gene which is responsible for production alcohol dehydrogenase which forces this enzyme to turn improbably intensively ethanol in acetic aldehyde. Besides, at a half of such people ability to turn acetic aldehyde in acetic acid is reduced. Thus, after alcohol consumption acetic aldehyde collects in an organism that causes effect of “an alcoholic flush” with the subsequent hardest hangover. For this reason among such people there is a smaller number of alcoholics.
It is often affirmed that the hangover becomes worse with age; this phenomenon is normally connected with deterioration of supply of an organism with alcohol dehydrogenase — the enzyme participating in a metabolism of alcohol.