Blood alcohol concentration
From Drug Rehab Wiki
Blood alcohol concentration, also known as BAC or blood alcohol content, is a scientific method used to measure the level of alcohol intoxication in law enforcement or medical settings. It is usually written as the percent of alcohol within the blood, but without the percent sign. For example, a blood alcohol concentration of .08 means .08% not 8%, as it would be read in other mathematical contexts. Unfortunately, many jurisdictions vary in how they determine blood alcohol concentration.
In most jurisdictions in the US, a BAC of .08 means that the person could be found legally intoxicated and, therefore, shouldn’t be driving. Thirty years ago, this limit was a generous .15. In some countries, including many counties in Eastern Europe, there is zero tolerance for driving after drinking alcohol, whereby it is a crime to drive with any level of alcohol in the blood. The vast majority of countries limit BAC to .05. While the above limits apply to adults most countries, including the US, show zero tolerance for underage drinking.
The number of drinks required for a person to reach a particular blood alcohol concentration will vary based on the person’s weight, body fat, sex, stomach contents, health, and prior drinking history. Further, differences in how the body metabolizes, excretes and evaporates alcohol will all affect the BAC. Although the body’s liver will eventually metabolize over 95% of the alcohol, first into acetaldehyde (more toxic than the original ethanol) and then into acetic acid, the rest will be eliminated from the body via feces, milk, saliva, breath, sweat and urine. People whose bodies have trouble converting to acetaldehyde, such as the majority of Asians, will experience stronger hangovers.
Blood alcohol concentration is significant as there is a direct correlation between BAC and how alcohol affects a person, both physically and mentally. When a person has a BAC below .03, he or she will usually appear completely normal, although some changes could be identified with specific tests. A blood alcohol concentration above .03 but below .06 typically impairs concentration and results in marked changes in behavior such as slight euphoria, increased relaxation and chattiness and reduced inhibition. This level of intoxication is more commonly known as being “buzzed.”
When blood alcohol concentration rises between .06 and .09, however, the drinker may become legally intoxicated and will experience significant impairment in reasoning, depth perception, glare recovery and peripheral vision. Blood alcohol concentrations above .10 but below .20 result severe side effects including decrease in reflexes, reaction time, gross motor control, staggering and slurred speech. Given that these skills play a vital role in night driving, it is no surprise that a significant number of drunk driving accidents happen when a driver is at this level of intoxication.
When a drinker’s body has reached blood alcohol concentrations above .20, he or she can be in serious trouble. Not only is this the BAC at which blackouts occur, but there can also be decreases in breathing, heart rate and central nervous system functioning. When blood alcohol concentration reaches above .30, death can occur and will most likely occur when BAC reaches .50.
