Understanding your body and alcohol: What does a .08 blood-alcohol level really mean?

BAC varies greatly based on gender, weight

One of the biggest challenges in combating drunk driving is the lack of understanding of the definition of driving drunk.  It is illegal to drive at a .08 BAC (blood-alcohol concentration) or higher in all 50 states.

But many people are unclear as to what a .08 actually means. That's because there's no easy answer.

How many drinks it takes to get you to .08 varies greatly depending on your gender, weight, how much time passes between drinks and how much you've eaten.

Your age, metabolism and whether any prescription drugs are in your system also impact your blood-alcohol.

For example, you could drink a certain amount on one day and be under the limit but have the same amount the next day and be over .08.  The only completely safe limit is to avoid drinking entirely when driving.

According to the National Institute of Health, a .08 is roughly equivalent to 4 drinks for a 180-pound male. For a 140-pound female only 2 drinks could put her at a .07.  Three drinks would raise her blood-alcohol to .10.

While blood-alcohol levels do decrease over time, it's typically by only about .015 an hour.  So a person who is at a .08 would likely need 6 hours to completely sober up.

One drink is defined as a 12-oz. beer, a 5-oz. glass of wine or 1.5 oz. of a 72-proof distilled liquor.

But even if a driver is below a .08, studies show driving skills are significantly affected at the .04 level. That would be just two drinks for the average male and 1.5 drinks for the average female.

It's also important to remember drivers can be arrested for driving under the influence even if they test below a .08.

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