THE PHYSIOLOGICAL EFFECTS OF ALCOHOL

First and foremost, alcohol is classified as drug – a very strong CNS depressant.  The primary depressant effect of alcohol occurs in the brain and spinal cord.  Many people think of alcohol as a stimulant because of the way most users feel consuming a serving or two of their favorite drink.  Any temporary sensations of jubilation, boldness, or relief are attributable to alcohol’s ability as a depressant drug to release personal inhibitions and provide temporary relief from tension.

Factors That Influence the Absorption of Alcohol

The absorption of alcohol is influenced by several factors, most of which can be controlled by the individual.  These factors include the following:

·         Strength of the beverage.  The stronger the beverage, the greater the amount of alcohol that will accumulate within the digestive tract.

·         Number of drinks consumed.  As more drinks are consumed, more alcohol is absorbed.

·         Speed of consumption.  If consumed rapidly, even relatively few drinks will result in a large concentration gradient that will lead to high blood alcohol concentration.

·         Presence of food.  Food can compete with alcohol for absorption into the bloodstream, slowing the absorption of alcohol.  When alcohol absorption is slowed, the alcohol already in the bloodstream cab be removed.  Slow absorption favors better control of blood alcohol concentration.

·         Body chemistry.  Each person has an individual pattern of physiological functioning that may affect the ability to process alcohol.  For example, in some conditions, such as that marked by “dumping syndrome,” the stomach empties more rapidly than is normal, and alcohol seems to be absorbed more quickly.  The emptying time may be either slowed or quickened by anger, fear, stress, nausea, and the condition of the stomach tissues.

·         Gender.  Women produce much less alcohol dehydrogenase than men do.  This enzyme is responsible for breaking down alcohol in the stomach.  As a result, women absorb about 30% more alcohol into the bloodstream than men, despite an identical number of drinks and equal body weight.

Three other reasons help to explain why women tend to absorb alcohol more quickly than men of the same body weight: (1) women have proportionately more body fat than men.  Since alcohol is not stored easily in fat, it enters the bloodstream relatively quickly. (2) Women’s bodies have proportionately less water than men’s bodies of equal weight.  Thus alcohol consumed does not become as diluted as in men. (3) Alcohol absorption is influenced by a woman’s menstrual cycle.  Alcohol is more quickly absorbed during the premenstrual phase of a woman’s cycle.  Also, there is evidence that women using birth control pills absorb alcohol faster than usual.

With the exception of a person’s body chemistry and gender, all factors that influence absorption can be moderated by the alcohol user.

Blood Alcohol Concentration

A person’s blood alcohol concentration (BAC) rises when alcohol is consumed faster than it can be removed (oxidized) by the liver.  A fairy predictable sequence of events takes place when a person drinks alcohol at a rate faster than one drink every hour.  When the BAC reaches 0.05%, initial measurable changes in mood and behavior take place.  Inhibitions and everyday tensions appear to be released, while judgement and critical thinking are somewhat impaired.  This BAC would be achieved by a 160-pound person consuming about two drinks in an hour.

At a level of 0.10% (one part alcohol to 1000 parts blood), the drinker typically loses significant motor coordination.  Voluntary motor function becomes quite clumsy.  At this BAC, most states consider a drinker legally intoxicated and thus incapable of safely operating a vehicle.  Although physiological changes associated with this BAC do occur, certain users do not feel intoxicated or do not outwardly appear to be impaired.

As the BAC rises from 0.20% to 0.50%, the health risk of acute alcohol intoxication increases rapidly.  A BAC of 0.20% is characterized by the loud, boisterous, obnoxious drunk person who staggers.  A 0.30% BAC produces further depression and stuporous behavior, and the drinker becomes so confused that he or she may not be capable of understanding anything.  The 0.40% or 0.50% BAC produces unconsciousness.  At this level, a person can die, since the brain centers that control body temperature, heartbeat, and breathing may virtually shut down.

An important factor influencing the BAC is the individual’s blood volume.  The larger the person, the greater the amount of blood into which alcohol can be distributed.  Conversely, the smaller person has less blood into which alcohol can be distributed, and as a result, a higher BAC will develop.

Sobering Up

Alcohol is removed from the bloodstream principally through the process of oxidation.  Oxidation occurs at a constant rate (about ¼ to 1/3 ounce of pure alcohol per hour) that cannot be appreciably altered.  Since each typical drink of beer, wine, or distilled spirits contains about ½ ounce of pure alcohol, it takes about 2 hours for the body to fully oxidize one typical alcoholic drink.

Although people may try to sober up by drinking hot coffee, taking cold showers, or exercising, the oxidation rate of alcohol is unaffected by these measures.  Thus far the FDA has not approved any commercial product that can help people achieve sobriety.  Passage of time remains the only effective remedy for diminishing alcohol’s effects.

First Aid for Acute Alcohol Intoxication

Not everyone who goes to sleep, passes out, or becomes unconscious after drinking has a high BAC.  People who are already sleepy, have not eaten well, are sick, or are bored may drink a little alcohol and quickly fall asleep.  However, people who drink heavily in a rather short time may be setting themselves up for an extremely unpleasant, toxic, potentially life-threatening experience because of their high BAC.

Although responsible drinking would prevent acute alcohol intoxication (poisoning), it will never be a reality for everyone.  As a caring adult what would you know about this health emergency that may help you save a life – perhaps even a friend’s life?

The first real danger signs to recognize are the typical signs of shock.  By the time these signs are evident, a drinker will already be unconscious.  He or she will not be able to be aroused from a deep stupor.  The person will probably have a weak, rapid pulse (over 100 beats per minute).  The skin will be cool and dump, and breathing will be increased to once every 3 or 4 seconds.  These breaths may be shallow or deep but will certainly occur in an irregular pattern.  Skin will be pale or bluish.  (in the case of a person with dark skin, these color changes will be more evident in the fingernail beds or in the mucous membranes inside the mouth or under the eyelids.)  whenever any of these signs are present, seek emergency medical help immediately.

Involuntary regurgitation (vomiting) can be another potential life-threatening emergency for a person who has drunk too much alcohol.  When a drunker has consumed more alcohol than the liver can oxidize, the pyloric valve at the base of the stomach tends to close.  Additional alcohol remains in the stomach.  This alcohol irritates the lining of the stomach so much that involuntary muscle contractions force the stomach contents to flow back through the esophagus.  By removing alcohol from the stomach, vomiting may be a life-saving mechanism for conscious drinkers.

An unconscious drinker who vomits may be lying in such a position that the airway becomes obstructed by the vomitus.  This person is at great risk of dying from asphyxiation.  As a first-aid measure, unconscious drinkers should always be rolled onto their sides to minimize the chance of airway obstruction.  If you are with someone who is vomiting, make certain that his or her head is positioned lower than the rest of the body.  This position minimizes the chance that vomitus will obstruct the air passages.

It is also important to keep a close watch on anyone who passes out from heavy drinking.  Party-goers sometimes make a mistake of carrying these people to bed and then forgetting about them.  Monitoring the physical condition of anyone who becomes unconscious from heavy drinking is crucial because of the risk of death.  Observe the person at regular intervals until he or she appears to be clearly out of danger.  This may mean an evening of interrupted sleep for you, but you could save a friend’s life.  Are you aware of any recent alcohol-related death among U.S college students?