Blood Alcohol Content

Blood alcohol content, or blood alcohol concentration (BAC), refers to the percentage of alcohol in the bloodstream. A BAC of .10% means that there is 1 part alcohol for every 1000 parts blood in a person’s bloodstream.

Factors that determine BAC are the number of drinks consumed, the amount of time in which they are consumed, your body weight, whether you’re male or female, any medications or other drugs being used, and, to a lesser extent, the amount and type of food consumed while drinking.

Alcohol is absorbed into the bloodstream quickly and completely, with about 20% absorbed through the stomach and 80% through the upper intestine. It is then distributed evenly throughout the body, coming in contact with all organs and cells.

Roughly 95% of the alcohol that is ingested metabolizes in the liver and 5% is excreted via urine and through the lungs. (This is how breathalyzer tests work.) Alcohol is metabolized at a constant rate in most individuals, usually about ¾ of an ounce per hour. Drinking more than that increases blood levels, induces intoxication, and depresses the activity of all brain cells.

At a BAC of .01-.03%, aside from slight elevations in mood for some, there are little apparent effects. At .04-.06% we begin feeling relaxation, sensations of warmth, and minor impairment of reasoning and memory. From .07-.09% we see impairment of balance, speech, and vision control. At this point you are considered intoxicated and driving is illegal and extremely dangerous. Most states currently have a blood alcohol content limit of .08%. If an individual were to keep drinking, from .10-.12% there is significant impairment of motor coordination, slurred speech, and loss of judgment. From .13-.20% BAC all of the symptoms above are magnified and dysphoria (anxiety and restlessness) sets in. At a BAC of .25% an individual is severely intoxicated, needs assistance walking, experiences mental confusion, and may begin to experience nausea or vomiting. From .35-.40% and up, a person will likely experience a loss of consciousness, onset of coma, and a likelihood of death due to respiratory failure.