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Wellness Center

Blood Alcohol Levels and Alcohol Impairment

Blood Alcohol Content (BAC)

The amount of alcohol in your blood stream is referred to as Blood Alcohol Content (BAC). It is recorded in milligrams of alcohol per 100 milliliters of blood, or milligrams percent. For example, a BAC of .10 means that 1/10 of 1 percent (or 1/1000) of your total blood content is alcohol. When you drink alcohol it goes directly from the stomach into the blood stream. This is why you typically feel the effects of alcohol quite quickly, especially if you haven't eaten in a while.

BAC depends on: 1. Amount of blood (which will increase with weight) and 2. The amount of alcohol you consume over time (the faster you drink, the higher your BAC, as the liver can only handle about a drink per hour--the rest builds up in your blood stream).

Understanding the effects of a rising BAC can be very useful in controlling drinking.

Below are the effects of increasing BAC:
  • .02 Mellow feeling. Slight body warmth. Less inhibited.
  • .05 Noticeable relaxation. Less alert and self-focused. Coordination impairment begins.
  • .08 Drunk driving limit. Definite impairment in coordination and judgment.
  • .10 Noisy. Possible embarrassing behavior. Mood swings. Reduction in reaction time.
  • .15 Impaired balance and movement. Clearly drunk.
  • .30 Many lose consciousness.
  • .40 Most lose consciousness. Some die.
  • .50 Breathing stops. Many die.

BAC Calculator


As can be seen, the most reliably pleasurable effects of alcohol occur when BAC rises to about .03-.05. Alcohol researchers have discovered that low levels of alcohol have a specific effect on thinking; alcohol results in a reduction of "self-monitoring." What this means is that small quantities of alcohol enable you to take your mind off yourself and your worries. Not surprisingly, this effect reduces tension and enhances relaxation in many people. Some people find this effect so rewarding that they continue to drink. Unfortunately, the effect on self monitoring diminishes as BAC rises above .05. Instead emerge a host of negative effects, such as less emotional control, coordination and judgment impairment, hangovers and obnoxious behavior.

Remember - it is illegal to drive with a BAC of .08% or higher (if you are under 21 it is illegal to drive with a BAC of .02% or higher) BACs above .25- at risk of an overdose (alcohol poisoning)

Other Factors Impacting BAC and Impairment
In addition to the amount of alcohol consumed, the speed at which it is consumed, and your tolerance, here are a number of other factors that will also affect how quickly and to what degree you will get impaired if you choose to drink:
  • Food in the stomach will slow the absorption of alcohol into the bloodstream and delay impairment. The type of food ingested (carbohydrate, fat, protein) has not been shown to have a measurable influence on BAC. However, we do know that the larger the meal and the closer the time between eating and drinking, the lower the peak blood alcohol content. Studies have shown reductions in peak blood alcohol content (as opposed to those of a fasting individual under otherwise similar circumstances) of between 9 percent and 23 percent.
  • Alcohol mixed with carbonated beverages such as Coca-Cola or Seven Up will be absorbed more quickly into the bloodstream. This is also true for champagne and wine coolers.
  • Women who are pre-menstrual and sometimes those on birth control pills tend to get more impaired more quickly.
  • Strong emotions — anger, fear, loneliness — tend to hasten impairment.
  • If you are tired, sick or just getting over an illness, you tend to get more impaired more quickly.
  • Mixing alcohol with other drugs often leads to increased impairment in a shorter period of time.

For more information contact the Wellness Center, at (509) 963-3213.


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