How Your Breathe Affects Blood Alcohol Breath Test Results

California DUI defense lawyer Lawrence Taylor cites several fascinating studies in his DUI blog suggesting that how you breathe can dramatically impact the blood alcohol reading generated by a breath test. For example, holding your breath for 30 seconds increased the blood alcohol content of your breath by over 15%. Hyperventilating for 20 seconds decreased the BAC by 10%.

In his post about breathing and breath tests, Attorney Taylor also cites a research study by a University of Washington Professor of Physiology who found that the last part of your exhalation has a higher alcoholic content than the first part, meaning that a police officer’s command to “blow harder” may very well result in a higher BAC reading on the breath test.

Georgia Courts have long rules that arrest scene breath tests are not admissable evidence. Mr. Taylor explains the science behind the reasons breath tests are flawed in another post on his blog. It would be interesting to know the psychological impact that a failed breath test has on a defendant’s subsequent decisions to admit to alcoholic consumption or to not assert his other available rights.

1 comment on this post.
  1. Brittani Vanderberg:

    I live in kennesaw georgia and I was recently arrested for minor possesion of alcohol. I had no alcohol in my possesion nor had i had anything to drink but i blew a .o1 at the scene and was arrested. The thing is i had gum in my mouth and i always thought they had to wait a certain amount of time to make you blow well i spit my gum out and then blew. The did not test me again at the station. The officer did not put what i blew on my ticket now my police report i plan on fighting this charge i was wondering what the best information to use would be

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