The hangover is a mild manifestation of alcohol withdrawal. In the earlier
stages, it is the all too familiar "hangover headache." This is more likely
related to vasular changes and has nothing to do with the brain. The brain itself has no
pain receptors. So, any headache pain must be from nerves surrounding the lining, skin,
vessels, or muscles. Although the alcohol has been eliminated, the body's chemical balance
has been upset, digestive organs have been abused, and an overpowering fatigue is felt.
There is lack of consensus among researchers on the cause of hangovers. The explanations
most frequently cited are decribed below.What are the causes of a hangover?
Central Nervous System (CNS)
Alcohol has a depressant effect on the CNS. With abstinence, this depressant affect is
removed and there is a "rebound" of sensitivity to stimuli. An area of the CNS
particulary affected is the reticular activating system which oversees the general arousal
level and CNS activity.
Congeners
The congeners or chemicals added to color, flavor, preserve, or stabalize alcoholic
beverages may cause headaches.
Dehydration
Alcohol suppresses the hormone regulating the amount of urine produced, therefore, too
little of the hormone is released and the kidneys form excessive urine. The kidney's
capacity to reabsorb water is diminished and water is excreted from the body. Therefore,
intoxication causes the body to lose water (including vitamins and minerals). This
produces the sensation of thirst or "cotton mouth."
Depleted Body Blood Sugar/Glucose
Alcohol depletes the body of its blood sugar causing a hypoglycemic state. In this
state there is a reduced concentration of blood sugar. The brain is deprived of its proper
nourishment. Symptoms include hunger, weakness, nervousness, sweating, headache, and
tremor.
Deprivation of Brain Oxygen
The brain is the organ most sensitive to alcohol. It also receives less oxygen when
alcohol is present, which adds to the feeling of fatigue the following morning.
Stomach Irritant/Digestion Rebound
Alcohol is an irritant which produces the flow of gastric juices in the stomach lining,
causing nausea and vomiting. The next morning, a "rebound effect" is produced as
the stomach works extra hard to neutralize the gastric acid. This may cause an upset
stomach.
Sleep Disturbance
Alcohol alters the neurochemical balance within the brain. Although some people fall
asleep faster with a drink, alcohol depresses REM (Rapid Eye Movement) sleep and causes
more sleep disturbance later at night. REM sleep is an important component of a healthy
sleep cycle. Even if people think they sleep well, the loss of REM sleep makes people want
to sleep longer in the morning and would then feel tired during the day. Deprivation of
REM sleep is what causes people to feel tired.
Vascular Changes
Alcohol is a vasodilator. It increases blood flow to the extremities. One reason for
morning chills may be a rebound effect. As the blood vessels constrict, there is reduced
blood flow to the extremities, and therefore less warmth. These vascular changes have also
been related to the hangover headaches. Migraine sufferers should avoid alcohol because
use may aggraavate their tendency to vascular headaches.
Are there any cures for a hangover?
The simple cause is too much alcohol. The only prevention is to avoid drinking too
much, too fast. There is no cure for a hangover. Once excessive drinking has taken place,
only time will cure a hangover -- none of the many popular home remedies have been shown
to be cures.
