A Guide to Understanding Blood Alcohol Concentration and Alcohol Impairment

Alcohol is one of the most common forms of addiction. In moderate quantities it is just an inebriant, but in larger doses it begins to impair our intellectual and mental capacity. What actually matters is the concentration of alcohol in blood, which depends not only on the quantity ingested but also the rate of ingestion as well as the capacity of the body to detoxify and get rid of it

Alcohol: The Most Commonly Consumed Non-Nutritious Substance

Alcohol is perhaps the most commonly consumed non-nutritious substance among the human beings. Right from the very ancient times, it has been an object of desire, primarily because of its effects on the brain. However, not all of its effects can be considered desirable.

As a very permeable substance, alcohol can permeate through cell membranes of most cells including those of the brain, once it has entered the blood stream. Its effects on the brain are generally related to its blood level, though the actual manifestations may differ from person to person, depending on their innate metabolic characteristics, and the amount of their usual alcohol consumption.

Alcohol Metabolism in the Body

Alcohol is metabolized by the microsomal enzyme system in liver, and the enzyme system can grow to take care of the larger and more frequent intake of alcohol, thereby adopting the person's capacity to tolerate even larger doses of alcohol. This is the main reason, why a person who is not used to taking large doses of alcohol regularly may be much more vulnerable to its effects than a habitual drinker.

In the brain, the effects of alcohol are to primarily depress the central nervous system neurons. However, its first effects often given an almost opposite impression. Alcohol sensitizes the N-methyl-D-aspartate (NMDA) system of brain making it more receptive to 'glutamate', which is a neurotransmitter and increases brain activity at lower levels of alcohol (0.03 to 0.12%), leading to a kind of euphoria and pleasure seeking behavior.

Effects of Alcohol on Brain

The first casualty of the depressive activity of alcohol is one's sense of inhibition that is primarily derived from our understanding of consequences of our actions. As the person loses the ability to think of and take cognizance of the results of his/her actions, the inhibition in behavior gets suppressed. So a person who would otherwise not quarrel with his friend in public because of the adverse impact it will have on his image, will no more bother about the impacts of his action and do just what he really desired.

The same is the effect on driving. As the brain gets depressed, the abilities of the brain, including driving are diminished but because the ability to understand and take stock of the consequences of one' actions is lost even further, a drunk man, not in a condition to drive safely, still wants to drive, thereby creating a danger for his own as well as other's lives.

As the blood level rises, the brain gets suppressed further, to the extent that one loses consciousness.