At Any Age, It Does Matter:
Substance Abuse and Older Adults (for Professionals)

Module 3: Alcohol and Aging - Page 3 of 11

Blood Alcohol Levels and Behaviors at Various Levels

Blood alcohol level (BAL) is the concentration of alcohol in the blood. BAL is calculated using the weight of alcohol (milligrams) and the volume of blood (deciliter). This yields a blood alcohol concentration (BAC) that can be expressed as a percentage (e.g., .10 percent alcohol by volume) or as a proportion (e.g., 100 mg/dL). For example, a BAC of .08 percent means a concentration of 80 mg/dL.

In a healthy person, one standard drink raises the BAL about 20 mg/dL. (One standard drink=12 oz. beer, 5 oz. table wine, 1½ oz. 80 proof liquor, or 4 oz. liqueur). The body metabolizes alcohol at a rate of about 20 mg/hour.