Alcohol Abuse - How alcohol affects the body
The overall effects of alcohol on the body and on behavior vary a great deal depending on many factors. One factor should be noted at once: if the blood reaching the brain contains a certain percentage of alcohol, there are marked changes in reaction. As the percentage increases, the functioning of the brain and central nervous system is increasingly affected. As the alcohol is gradually metabolized and eliminated, the process reverses itself.
If at any given time the blood contains a concentration of about 3/100 of one percent (0.03 percent), no effects are observable. This amount will make its way into the bloodstream after you have had a highball or cocktail made with one and one-half ounces of whisky, or two small glasses of table wine, or two bottles of beer. It takes about two hours for this amount of alcohol to leave the body completely.
Twice that number of drinks produces twice the concentration of alcohol in the bloodstream (0.06 percent) with an accompanying feeling of warmth and relaxation.
If the concentration of alcohol in the bloodstream reaches 0.1 percent—when one part of every thousand parts of blood is pure alcohol—the person is legally drunk in most states. The motor areas of the brain are affected; there is a noticeable lack of coordination in standing or walking. If the percentage goes up to 0.15 percent, the physical signs of intoxication are obvious, and they are accompanied by an impairment of mental faculties as well.
A concentration of as much as 0.4 percent can cause a coma. At the level of 0.5 to 0.7 percent there may be paralysis of the brain centers that control the activities of the lungs and heart, a condition that can be fatal.
Alcohol affects the brain and nervous system in this way because it is a depressant and an anesthetic.