a library of information on how to mix exotic drinks,
they could find little about what happens after the
The person who wants to drink responsible y must
know the short-term and long-term effects of alcohol on
the body. Those who want to understand the social
custom of drinking, problem drinking, and alcoholism
must also know these effects.
SHORT-TERM EFFECTS. Most people drink
alcoholic beverages to get feelings of pleasure as well
as to relieve tension. No doubt that is the reason for the
popularity of alcohol as a social beverage. Drinking has
become such a familiar part of our society that we do
not think of alcohol as a drug. However, it is as much a
drug as one prescribed in carefully regulated dosages by
Alcohol affects the whole body through the central
nervous systemthe brain. Alcohol does not act directly
on the tongue or legs to cause the familiar signs of
slurred speech and an unsteady gait connected with
drunkenness. Instead, it affects the parts of the brain that
control those parts of the body.
Alcohol can act as a stimulant at low doses and as a
brain depressant at higher doses. The speed with which
alcohol brings on drunkenness and drunken behavior
depends upon the rate of its absorption into the
bloodstream and a person's tolerance for alcohol.
Although the body must digest food before it can
enter the bloodstream, it does not have to digest alcohol.
Alcohol immediately passes directly through the wall of
the stomach and small intestines into the bloodstream.
Then the blood rapidly carries it to the brain.
Even the first few sips of an alcoholic beverage may
cause changes in mood and behavior. These changes
may be influenced by what the person has learned to
expect from previous drink experiences.
Alcohol is metabolized (burned and broken down)
in the body at a fairly constant rate. As a person drinks
faster than the alcohol can be burned, the drug
accumulates in the body. That results in higher and
higher levels of alcohol in the blood.
BEHAVIOR. The first consistent changes in mood and
behavior appear at blood-alcohol levels of
approximately 0.05 percent; that is, 1 part alcohol to
2,000 parts blood. That level would result if a 150-pound
person took two drinks in succession. A blood-alcohol
level of 0.05 percent can affect a persons thought,
judgment, and restraint and cause the person to feel
carefree. The person feels a release from many ordinary
tensions and inhibitions; in other words, the person
loosens up. Most people drink in moderation mainly to
achieve this relaxed state.
As more alcohol enters the blood, the depressant
action of alcohol involves more functions of the brain.
At a level of 0.10 percent (1 part to 1,000), voluntary
motor actions-hand and arm movements, walking, and
sometimes speech-become clumsy.
A level of 0.20 percent (1 part to 500) measurably
impairs the controls of the entire motor area of the brain
as well as that part of the brain that guides emotional
behavior. At this stage the person will stagger and may
want to lie down. The person may also become easily
angered, may become boisterous, or may weep. The
person is drunk.
A concentration of 0.30 percent (1 part to 300) dulls
the persons response to stimulus and understanding
controlled by the deeper areas of the brain. At this level
a person may be confused or may lapse into a stupor.
Although aware of surrounding sights and sounds, the
person has poor understanding of what he or she sees or
With 0.40 to 0.50 percent alcohol in the blood (1
part to 250 or 200), the person becomes unconscious and
may go into a coma. Still higher levels of alcohol block
the center portions of the lower brain that control
breathing and heartbeat, causing death to occur.
This progression of effects is not unique to alcohol.
Other hypnotic-sedative drugs, such as barbiturates,
ether, and chloral hydrate, can also produce this
progression of effects.
Blood-alcohol levels have important legal
implications. In most states, a person with a
blood-alcohol level of 0.05 percent or less is legally
presumed sober and in condition to drive a motor
vehicle. However, in some states, a person with a level
of 0.10 percent or 0.08 percent is legally presumed
intoxicated or under the influence; in others, the
0.15-percent level means legal impairment.
CHRONIC HEAVY DRINKING. Drinking large
amounts of alcohol for an extended length of time
reduces the brains sensitivity to the alcohol. Therefore,
a person must drink greater amounts of alcohol to feel
its effects. This change in the sensitivity of the brain is
called tolerance. Increased tolerance is a symptom of all
chronic users of addictive drugs and is believed to be the
basis of addiction or dependence.