How to Understand Blood Alcohol Levels

Reference: eHow.com


The level of alcohol in the blood is measured by BAC, which stands for blood alcohol content or concentration. Typically, this number is measured by the mass of alcohol per unit of volume of blood. The procedure for measuring BAC as well as the legal limit for drivers differs by country. If you are drinking, it's a good idea to be aware of your own body as well as the limits.

Instructions

1. Step 1

   Know the legal limits of the country and state you are in. In much of the world, the legal limit is .05 percent BAC. In the United State, federal regulations dictate that the legal limit is no more than .08 percent, but many states have lower limits.

2. Step 2

   Learn the units BAC is measured in. In the United States, BAC is typically measured in a percentage derived from determining the grams of alcohol consumed per 100 grams of blood in the individual's body.

3. Step 3

   Study the conversion units. Most alcoholic beverages will have a gram measurement listed on the container, but if they don't you will need to convert liters or milliliters into grams. You will also need to determine the individual's weight in grams, which you can do by dividing the number of pounds by 2.205.

4. Step 4

   Know the alcohol content of the beverage you are drinking. This can be found using the proof, which is twice the percentage of alcohol in the drink. For example, 100 proof liquor is 50 percent alcohol by content.

5. Step 5

   Calculate the blood or water percentage of body weight. When determining how much alcohol is in the blood, you will use the person's weight in kilograms to determine the amount of blood in kilograms. Men are typically about 58 percent water or blood, while women are 49 percent. To find the blood content of a man's body, then, you need to convert his weight from pounds to kilograms to grams and multiply by .58.

6. Step 6

   Recognize that mathematical calculations are tedious and may not reflect the exact BAC of an individual. Metabolic rate and body fat percentage both influence the rate at which alcohol will leave the blood stream.

7. Step 7

   Grasp the difference between BAC and tolerance for alcohol. People who are heavy drinkers may develop a high tolerance for alcohol and seem fine even when they are over the legal limit. Individuals who are unable to gauge their own BAC may want to acquire a device for measuring the alcohol content in their breath before driving.

8. Step 8

   Use informal rules to gauge your BAC. Generally, two drinks will raise the BAC by .05 percent. A drink is considered to be one can of beer, one small glass of wine or one small shot. If you're unsure of your BAC and how to calculate it, aim to drink no more than two drinks an hour to remain within the legal limits.

9. Step 9

   Be aware that law enforcement officials may use a variety of methods to determine your BAC or level of impairment, from a breath test to a sobriety test to lab tests done after the fact.