Blood Alcohol Concentration



Blood Alcohol Concentration (BAC) Questions and Answers


What is BAC?


The amount of alcohol in an individuals body is measured by the weight of the alcohol per volume of blood. This can be better explained by understanding how alcohol is absorbed.  Alcohol is absorbed first through the walls of the stomach, and small intestine, next going into the bloodstream, and finally traveling throughout the body and to the brain. The absorption of alcohol does not take long. Typically, alcohol can be measured within 30 - 70 minutes after a person has had alcohol.

Does the type of alcohol your drinking make a difference in your BAC?

The type of alcohol consumed (wine, spirits, or beer) does not make a difference on BAC.  Overall, the amount of alcohol that is consumed over a given time period, is what effects your Blood Alcohol Concentration.  For example, the amount of alcohol in one 12 ounce beer is equal to one shot of distilled vodka or one 5 ounce glass of wine,  all containing about half an ounce of alcohol (.54 ounces).

What affects my BAC?

A number of factors play into your BAC.  The number of alcoholic drinks you have is the biggest factor. The more drinks you have, the higher your Blood Alcohol Concentration will be. Another factor that comes into play is how quickly you drink.  The faster you take in alcoholic drinks, the faster your BAC goes up than compared to consuming slowly over an extended period. Your gender also is a factor. Women have a higher percentage of body fat per pound of weight compared to men, which leaves them less water in the body to help move the alcohol through the body. Alcohol does not get absorbed in fat cells as easily as other parts of the body, leaving more alcohol remaining in the blood of women. The weight of a person also affect BAC. When a person weights more it means they have more water present in their bodies.  This water dilutes the consumed alcohol which in turn lowers the Blood Alcohol Concentration. One thing that does not change your BAC is the use of other medications or drugs.  However,  if you take drugs or certain types of medication while drinking alcohol, you may actually feel more impaired and your reaction time could be compromised while operating a vehicle.

How do I know when I'm Impaired?

Due to the number of factors that affect BAC it is difficult to know your own BAC or impairment level while drinking. Although, very small amounts of alcohol can affect your brain without your BAC going over the legal limit, this does not always mean you have the ability to drive safely. Sometimes, the failure to recognize your own alcohol impairment is the sign of impairment. A person will usually be too impaired to drive a vehicle before looking, or acting drunk.

 Knowing when I'm impaired?

It has been proven that alcohol steadily decreases a person's ability to operate a motor vehicle safely.  The more a person drinks, the greater the effects of the alcohol. Each state has laws making it illegal to drive while under the influence with a BAC of .08 or higher. A driver can also come into scrutiny with a BAC under .08 when a law officer has probable cause based on the driver's behavior.


BAC Levels and Typical Symptoms
BAC   Typical Effects


 .02%
  • Some loss of judgement
  • Changing mood
  • More relaxed
  • Slight increase in Body temp.
 .05%
  • Lower inhibition
  • Lower alertness
  • Feeling "good"
  • Some loss of small muscle control ex.eyes
  • Impaired judgement


 .08%
  • Noticeable deterioration of reaction time
  • Unclear/Slurred Speach
  • Slow thought process
  • Poor coordination


What To Do If You Know You are Unable To Drive?


In the event that you have had too much to drink DO NOT DRIVE your vehicle. Have a friend or relative come pick you up, take advantage of public transportation, or call a taxi service.  These choices are far better than getting a DUI / DWI and in the long run much cheaper!  Ideally, have a plan in place before you ever leave the house like a designated driver.