Understanding The Physiology of Your BAC

If the police arrested you for driving under the influence of alcohol, you were likely asked to submit to a chemical test to determine the concentration of alcohol in your system.

When you take a breath, blood, or urine test, you might wonder how it works and why the police and prosecutors rely on the results to decide whether or not to charge you with a DUI.

Understanding the physiology of how alcohol works in your system might make the importance of your blood alcohol concentration clearer.

When you work with a DUI lawyer in Chester County at DiCindio Law, you might be able to successfully challenge the results of your chemical test and secure a better resolution to the charges against you.

Alcohol and Your Body

Ethanol, which is the chemical compound in alcoholic drinks, is a central nervous system depressant. When you drink, alcohol you ingest will not affect you until it reaches your central nervous system. The CNS is made up of your spinal cord, brain, and brain stem.

Ethanol reaches your brain through the bloodstream. The primary way alcohol reaches your blood is by drinking it. While there are other ways that alcohol can be introduced into your body, it is almost always introduced orally.

Absorption of Alcohol on an Empty vs. Full Stomach

When you drink alcohol, ethanol reaches your stomach before it enters your blood through absorption. You do not have to digest alcohol before it can be absorbed, and it can be absorbed through the stomach lining.

This means that alcohol absorption can occur rapidly, especially if you drink when you haven’t eaten. If you drink while eating, the process of absorbing alcohol will be slower.

When you drink on an empty stomach, you will absorb around 20% of the ethanol through your stomach lining. The other 80% will enter your small intestine and be absorbed into your blood without being digested.

If you eat food, it must be partially digested before it will be passed into your small intestine. The presence of food prompts a muscle to contract at the base of the stomach, closing off the entrance to your small intestine.

As long as this muscle is contracted, the passage to your small intestine will not be available to the contents of your stomach. While your body is digesting part of the food, it will also break down a portion of the alcohol in your stomach.

As digestion continues, the muscle will start to relax, allowing the partially digested food and alcohol to enter your small intestine. The slower process means that your body will absorb alcohol more slowly, preventing your blood alcohol concentration will be lower when you drink while eating food than if you drink on an empty stomach.

How Alcohol is Distributed in Your Body

Once alcohol is absorbed through your stomach and small intestine into your bloodstream, your blood will distribute it throughout your body. The alcohol will be distributed to your organs and tissues according to their different water contents.

A fairly large amount will be distributed to your brain. The brain has a fairly high water content, which alcohol has an affinity to. Since fat tissue contains little water, little alcohol will be distributed to your fatty tissue.

Since women have a higher percentage of fatty tissue and a lower concentration of water than men, a greater percentage of the alcohol that women drink will reach the brain. By contrast, men have a higher percentage of muscle tissue, which also contains a high water content.

This means that men experience a more diverse distribution of alcohol in their bodies. If a woman and man drink the same amount of alcohol, the woman’s BAC will climb higher than the man’s.

The Elimination Process

Immediately after your body absorbs alcohol, it will begin to try to eliminate it. Some of the alcohol you ingest will be expelled from your body directly through your urine, sweat, and breath. Your body will directly eliminate between 2% to 10% of the alcohol you ingest.

You will eliminate most of the alcohol through your body’s metabolic processes. During these processes, alcohol will undergo chemical changes by reacting with oxygen in your body.

It will continue changing until it is broken down into water and carbon dioxide, which will be expelled from your body through the processes of exhalation, sweating, and urination. Your liver metabolizes most of the alcohol you ingest, using an enzyme called alcohol dehydrogenase.

The speed at which your body will metabolize alcohol can vary. On average, your blood alcohol concentration will climb, peak, and then begin falling at a rate of approximately 0.015% per hour.

This means that if your BAC peaks at 0.15%, it will take your body around 10 hours to eliminate the alcohol from your system. Men eliminate around 66% of a single drink in an hour, but women only eliminate about 50% of a drink in one hour.

The rate that alcohol is absorbed into your bloodstream can be affected by whether you drink on an empty stomach and how fast you consume alcoholic beverages. It can also be affected by the number of drinks you consume in a sitting.

However, once alcohol is absorbed into your bloodstream, you can’t do anything to eliminate it faster. For example, drinking coffee, taking a shower, exercising, or breathing deeply will not cause you to eliminate alcohol more quickly.

Instead, your body’s metabolism will control how quickly alcohol will be eliminated.

How Alcohol Affects you

Many people wonder how much alcohol can be ingested before they will be impaired. However, this can vary from person to person, depending on their age, body composition, weight, gender, and other factors. Pennsylvania has established a legal limit of 0.08% for alcohol concentration.

However, some people might be impaired when they have a lower concentration of alcohol in their systems, and others might not be impaired even when they have a BAC at the legal limit.

In Pennsylvania, people can be charged with DUIs when they have lower BACs than 0.08% when their driving abilities are impaired. The number of drinks that it might take to reach a BAC of 0.08% will depend on the person’s age, sex, body composition, and weight.

For example, a man who weighs 175 pounds who drinks on an empty stomach might reach a BAC of 0.04% after drinking two beers. Reaching a BAC of 0.08% might take a total of four beers ingested one after another.

For an average-sized woman, drinking a couple of beers might cause her BAC to reach 0.08% even though she ingested fewer drinks than a man.

Contact Our DUI Law Firm in West Chester, PA

If you are facing criminal charges and need legal help, contact the West Chester, PA DUI lawyers at DiCindioLaw, LLC to schedule a free initial consultation.
DiCindio Law, LLC

29 S Walnut St
West Chester, PA 19382
(610) 430-3535

***This blog article is made available by the law firm publisher for educational purposes and to provide general information, not to provide specific legal advice. By reading, you understand that there is no attorney client relationship between you and the publisher. The above listed information does not include the entire crimes code, annotations, amendments or any recent changes that may be relevant. The information provided is for informational purposes only and may not reflect the most current legal developments. These materials are not intended, and should not be taken, as legal advice on any particular set of facts or circumstances. Please contact DiCindio Law, LLC for a consultation and to discuss what law is relevant to your case. ***