Understanding BAC and Levels of Impairment

20 May 2020

Blood alcohol content (BAC) levels represent the percentage of a person’s blood that is concentrated with alcohol. Having a BAC of .10 means that at least .1% of your bloodstream is composed of alcohol. In many states, the legal BAC limit to operate a motor vehicle is below 0.08. Anything higher than 0.08 is considered legally impaired and can result in a DUI.

Blood alcohol content

Your blood alcohol content level measures the amount of alcohol in your blood that is traveling through your entire body, to every organ, including your brain. According to AwareAwakeAlive, having a BAC between 0 and 0.05% represents mild impairment and can include the following:

  • Mild speech, memory, attention, coordination, and balance impairments.
  • Sleepiness and perceived beneficial effects, such as relaxation.

Keep in mind, as blood alcohol content increases, so does impairment. Increased impairment levels begin to occur between 0.06% and 0.15% BAC, and can include:

  • Moderate memory impairments.
  • Vomitting typiclaly occurs at this level — right around .120%
  • Significant impairments in all driving skills.
  • Perceived beneficial effects of alcohol, such as increased relaxation feelings.
  • Speech, attention, coordination, and balance further impaired.
  • Increased risk of aggression in some people.

Severe impariement occurs between 0.16% and .30%, and can incldue:

  • Speech, memory, coordination, attention, reaction time, and balance are significantly impaired.
  • Loos of consciousness in some people.
  • Judgement and decision-making dangerously impaired.
  • Vomiting and other signs of alcohol poisoning.

Unfortunatley, many people continue to drink even past severe BAC levels, subsequently reaching life-threatening levels. A life-threatening BAC level is anywhwere from 0.31% and above, and can incude:

  • Loss of consciousness.
  • Significant risk of death in the majorty of drinkers due to suppression of vital life functions.
  • Danger of life-threatening alcohol poisining.

Though the legal limit is .08%, driving skills can be significantly affected after just a few drinks. Even 1 drink can impaire someone who weighs around 120 pounds, giving them a .04% to .05% BAC level. Similarly, it takes a 200-pound man, on average, about 4 drinks to reach a BAC level of .08% and takes only 1.5 to 2 drinks for a 100-pound person to reach that level of impairment.

Drinking and driving remains a serious problem in the United States. No matter what, even if you think you have a full understanding of BAC levels, should operate a vehicel after drinking. Call a cab, get a car breathalyzer, or simply just stay where you are — do not drink and drive. Ever.

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