How Does Drinking on an Empty Stomach Effect My Breath or Blood Test Results?

Generally, when a person drinks on an empty stomach they will reach a higher blood alcohol concentration more quickly, and this higher concentration will last longer, then if the same amount of alcohol is consumed on a full stomach.  This is one reason some people get charged with drunk driving even when they think they are drinking responsibly.  They did not realize the little alcohol they had would put them over the legal limit.  Here’s why this is true:

There are three things that impact a person’s blood alcohol concentration.  These are alcohol absorption, distribution and elimination.  Various factors can potentially impact all three of these factors, and possibly increase a person’s breath test. Generally the absorption of alcohol is a function of food in the stomach, distribution is a function of the amount of water present in various tissues in the body and the elimination of alcohol is largely a function of a person’s prior exposure to alcohol.

Ethanol, which is also called “beverage alcohol” or simply “alcohol,” has many interesting traits and characteristics. Because of Ethanol’s unique molecular structure, it will begin to be absorbed into the blood as soon as it comes into contact with tissues in your body.  So, the absorption of alcohol will begin in your mouth.  However, about 80% of the absorption into your bloodstream will take place in the lower intestine. This means that anything that stands in the way of alcohol getting from your stomach into your small intestine will significantly delay absorption. Certain foods, such as those that are high in fats and proteins, require the most time to digest.  While you are digesting, a muscle between your stomach and your small intestine remains closed.  Then, as you’re done digesting, the muscle opens, and the contents of your stomach pass into the small intestine.  This typically happens over time, meaning smaller amounts of alcohol pass into your bloodstream for each unit of time.  Also, as you are drinking alcohol, some elimination takes place in the stomach, and some alcohol is passing into the blood through the stomach tissues and then is eliminated by the liver. This means there’s less alcohol available to pass into the small intestine when the digestion is complete.

On the other hand, if you drink on an empty stomach, then this muscle remains open, and the alcohol you drink will be dumped right into your small intestine, and then quickly absorbed into the bloodstream.  This causes a peak in your blood alcohol content, and this will result in a possibly much higher breath or blood test.  Because you have now dumped more alcohol into your bloodstream and have done so very quickly, your liver will be overwhelmed, and it will take longer to clear the alcohol from your bloodstream.

Most standard drinks contain enough alcohol to raise your bodily alcohol level by .02 – .025 per drink. Most people eliminate alcohol at a rate of .015 per hour for men, and .018 for women. Even though two standard drinks might result in a breath test result of .03 for most people drinking and eating together, this same two drinks could result in a breath test of .05 or even higher on an empty stomach.  This is because of the interplay between the three factors absorption, distribution and elimination.  Drinking on an empty stomach distorts all three, and results in a higher breath test result.

Don’t drink and drive is always your best option.  Since it’s not illegal to drink and drive, if you do decide to drink before driving, be sure to always have food in your stomach at the time you are drinking.