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Which Factors Influence Blood Alcohol Concentration?

by Oct 26, 2021Criminal Defense Attorney, Dea Cortney, DWI / DUI, Kevin Sieben, Sam Edmunds

Most of us have heard advice about how to control our level of intoxication while drinking. Common tips include, “Don’t have more than one drink per hour and you’ll be fine to drive,” and “Just have a glass of water between drinks if you need to drive home!” These are common guidelines many Minnesotans use to determine whether they can safely drive after having a couple drinks, but they ignore one giant problem: how much our blood alcohol concentrations can vary from person to person. 

While this advice could possibly be enough to keep a 6-foot-tall young man from receiving a DUI, the same can’t always be said for a petite middle-aged woman. To make matters worse, blood alcohol levels aren’t always an accurate predictor of intoxication. Here are some of the most common factors that may affect blood alcohol concentration from one person to the next. Consider where you fall on these spectrums before you decide whether to drive home from the party. Or, if you want our Minnesota DUI-DWI attorneys’ professional opinion — don’t get behind the wheel after even one drink if you want to guarantee you won’t be charged with a crime. 


This may be the most well-known factor that impacts how alcohol affects us. Most of us have seen firsthand that a taller or larger person can hold their liquor better than someone who has a short stature and a thin frame. It makes sense that the amount of alcohol we consume will turn into different ratios in the body based on its size. The larger a person’s body, the more blood it contains, and the less concentrated the alcohol will be.

Another size-related factor to consider is the ratio of muscle to fat in the body. Fatty tissue is low in water content which makes it difficult for these cells to absorb alcohol. Muscle, on the other hand, is higher in water content and will absorb alcohol. 


There’s a reason most people start to suffer from worse hangovers as they get older. We may have been able to bounce back quickly after a night of drinking when we were in college, but that ability fades as we age due to biological factors that are out of our control. As we get older, our ability to metabolize alcohol declines. This means the alcohol stays in our blood longer and increases our blood alcohol concentration more quickly. The amount of water in our body also decreases as we age, which means the ratio of alcohol in the blood will be increased compared to a younger drinker. 

Interaction with Medications

Certain prescription medications should not be mixed with alcohol because they can drastically affect your perceived level of intoxication. In most cases you may feel more drunk than your BAC actually reflects, which can affect your safety but may not affect your BAC measurement. However, certain prescriptions can also impact the way your body metabolizes alcohol. This may lead to an increase in blood alcohol concentration that you wouldn’t expect if you had not taken the medication. A few drinks can quickly put you into an extremely altered state.

Minnesota DUI Defense Lawyers See Inaccurate BAC Readings

There are so many factors that can affect your BAC, which in turn may affect your risk of being charged with a DUI if you choose to drink and drive. If you have been charged with a DUI and you believe your breathalyzer reading may have been inaccurate, be sure to retain a Minnesota DUI defense attorney in Minnesota right away. These tests are often inaccurate, especially if they are administered improperly, and they don’t always reflect the driver’s actual level of impairment. 

Our DUI defense lawyers in Minnesota and Wisconsin have had our clients’ DUIs thrown out based on poor BAC readings from breath, blood, and urine tests. Reach out to our Minnesota criminal defense attorneys as soon as possible to learn how we can help you protect your rights.

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