Blood Alcohol Concentration (BAC) Levels and Their Effects on the Body

Estimated Read Time: 4 Minutes

Alcohol's effects on the body

Getting into the swing of conference season this year, we decided to go with a fun new idea for a give away item – the Floome smartphone breathalyzer. The compact breathalyzer plugs into your smartphone and measures your Breath Alcohol Concentration (BrAC) using an app. While it may not be a compliant method for testing employees on the worksite, it is a fun tool for checking your BrAC at the end of a party or happy hour.

One thing about this breathalyzer  – it is only accurate 20 minutes after your last drink. If you take a swig of whiskey and blow into it, it’s going to give you some pretty crazy readings.

Blood Alcohol Concentration – the amount of alcohol in the bloodstream. If someone has a 0.08% BAC (the legal limit for driving), that means there are 0.08 grams of alcohol in a 100mL sample of blood. The body can only metabolize about 1 alcoholic drink per hour. Anything above this cannot be processed by the liver and will stay in the blood stream. Drinking more than 4 drinks in a 2 hour period results in an almost exponential increase in BAC level.

What’s the difference between BAC and BrAC? The difference between the two measurements is simple: Blood Alcohol Concentration (BAC) is a measurement of alcohol in the blood, while Breath Alcohol is a measurement of alcohol in the breath that indicates the amount of alcohol in the blood. Confused? Don’t worry about it. BrAC and BAC levels use the same measurements so a .02% BAC is equal to a .02% BrAC.

So, most of us know that the legal limit for driving is a BAC level of .08%. But that’s usually where our knowledge of BAC levels and their associated effects ends. The table below shows a more detailed list of different BAC levels and their associated effects.

Effects of Blood Alcohol Concentration

Source: Center for Disease Control, Effects of Blood Alcohol Concentration (BAC)

Looking through the table, you can see that the top of the spectrum at .15% BAC is the approximate equivalent of having 7 drinks. That’s a decent amount of alcohol. According to data provided by Lifeloc Technologies, At 0.15% you are 380 times more likely to be in a fatal accident than if you were sober. The national average for drunk drivers killed in car accidents is 0.17% BAC. Coincidently, that is also the national average for drivers arrested for drunk driving.

What about even higher BAC levels?

0.20% BAC – At this level, you would feel out of it, confused, and/or dizzy. You would require help to stand or walk. If injured, you may not feel the pain. Nausea and vomiting are likely to occur. The gag reflex is impaired and you can choke if you do vomit. Blackouts and “lost time” are likely.

0.25% BAC – At this level, all mental, physical, and sensory functions are severely impaired. Near total loss of motor function control, increased risk of asphyxiation from choking on vomit, and of seriously injuring yourself by falls or other accidents.

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0.30-0.40% BAC – This level of intoxication is extremely life threatening. You would have little comprehension of where you are. You may pass out suddenly and be difficult to awaken. You may become completely unconscious – coma or death is possible. This is the level of surgical anesthesia.

0.45% BAC Most people will die at this level of intoxication

How Long Before You Can Drive?

It takes about an hour to burn through .015% BAC or approximately 1 alcoholic drink. Each person metabolizes alcohol at a different speed. With this rate of metabolism in mind, let’s look at how long it takes to metabolize a 0.17% BAC level after a night of heavy drinking.

0.17% BAC level = Approx. 8-9 drinks

At a metabolism rate of .015% BAC per hour, it would take roughly 7 hours for your BAC level to be under the legal limit. It would take up to 12 hours for the alcohol to completely leave your system.

For Employers

With how long it takes to sober up after a night of heavy drinking, if an employee decides to drink heavily on a weeknight then they may still be under the influence when they come into work the next day. If they are required to operate dangerous machinery, they may be a safety hazard until they are completely sober. Educating your employees on this can help to prevent overdoing it on week nights. For those who still decide to come in after a night of heavy drinking, there’s always reasonable suspicion breath alcohol testing.