What are Blood Alcohol Content (BAC) Levels?

Although there is no one universally accepted standard for what is considered a “safe” level of drinking, the metric used to measure the amount of alcohol in a person’s bloodstream is called blood alcohol concentration, or BAC.1

A person’s liver can process about one standard drink an hour.1 According to the Centers for Disease Control and Prevention (CDC), a standard drink contains 0.6 ounces of pure alcohol.

Blood Alcohol Concentration (BAC) levels in standard drinks include:2

BAC levels for standard drinks

  • 12 ounces of beer, or one bottle at 5% alcohol.
  • 8 ounces of malt liquor at 7% alcohol.
  • 5 ounces of wine at 12% alcohol.
  • 1.5 ounces of hard liquor, or one shot, at 40% alcohol.

However, a person’s BAC level is not only affected by how much alcohol is consumed but by other factors such as an individual’s weight, gender, pattern of drinking, and genetics.

Side effects and impairments resulting from increasing blood alcohol levels include:1,3,4

  • Slowed reflexes and reaction time.
  • Slurred speech.
  • Memory trouble, blackouts, and memory loss.
  • Nausea and vomiting.
  • Loss of physical coordination.
  • Passing out.
  • Heartbeat, breathing, and blood pressure changes.

Across the U.S., in all states except for Utah, it is illegal for any persons 21 years or older to operate a vehicle with a BAC of 0.08%.5 In 2018, Utah changed their laws to reflect a BAC of 0.05% as the illegal limit for persons 21 years or older operating a vehicle.

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Understanding BAC Levels & Effects

Common symptoms, levels of impairment, and risks for various blood alcohol concentration (BAC) levels include:1,6 

  • 0.02%: This is the lowest level of intoxication with some measurable impact on the brain and body. You will feel relaxed, experience altered mood, feel a little warmer, and may make poor judgments.
  • 0.05%: At this level of BAC, your behavior will become exaggerated. You may speak louder and gesture more. You may also begin to lose control of small muscles, like the ability to focus your eyes, so vision will become blurry. Your judgment is impaired, and coordination is reduced. Tracking objects visually becomes more difficult, and your ability to respond to emergencies, like an object in your path, will be reduced. Your inhibitions will be lowered causing you to potentially engage in risky behaviors like drunk driving.
  • 0.08%: This is the current legal limit in the U.S., other than Utah, and at this level it is considered illegal and unsafe to drive. You will lose more coordination, so your balance, speech, reaction times, and even hearing will get worse. Standing still, focusing on objects, and evading obstacles are all much harder. Reasoning, judgment, self-control, concentration, and memory will be impaired. Short-term memory loss may start.
  • 0.10%: At this BAC, reaction time and control will be reduced, speech will be slurred, thinking and reasoning are slower, and the ability to coordinate your arms and legs is poor.
  • 0.15%: This BAC is very high. You will have much less control over your balance and voluntary muscles, so walking and talking are difficult. You may fall and hurt yourself. Vomiting may begin.
  • 0.20-0.29%: Stupor, confusion, feeling dazed, and disorientation are common. Standing and walking may require help, as balance and muscle control will have deteriorated significantly. Sensations of pain will change, so if you fall and seriously hurt yourself, you may not notice, and you are less likely to do anything about it. Nausea and vomiting are likely to occur, and the gag reflex will be impaired, which could cause choking or aspirating on vomit. Blackouts begin at this BAC, so you may participate in events that you don’t remember.
  • 0.30-0.39%: At this point, you may be unconscious and your potential for death increases. Along with a loss of understanding, at this BAC you’ll also experience severe increases in your heart rate, irregular breathing and may have a loss of bladder control.
  • 0.40% and over: This level may put you in a coma or cause sudden death because your heart or breathing will suddenly stop.

What is a Moderate Level of Alcohol Consumption?

BAC levels

When it comes to a “safe” level of drinking, the Dietary Guidelines for Americans 2015-2020 defines moderate drinking as up to 1 drink per day for women and up to 2 drinks per day for men.7

According to the Substance Abuse and Mental Health Services Administration (SAMHSA), binge drinking is classified as 4 or more alcoholic drinks for females or 5 or more alcoholic drinks for males on the same occasion (within a couple of hours of each other) on at least 1 day in the past month.7

Per SAMHSA, binge drinking on 5 or more days in the past month is considered heavy alcohol use which increases a person’ risk of developing an alcohol use disorder (AUD).7 Low-risk drinking for developing an AUD is defined as no more than 3 drinks on any single day and up to 7 drinks per week for women.7 For men, it is defined as no more than 4 drinks on any single day and up to 14 drinks per week.7

Seeking Help For Alcohol Addiction

If you suspect that you or someone you care about may be struggling with alcoholism, it may be time to seek professional help. No matter how serious the problem seems, recovery is possible. Research shows that “that about 1/3 of people who are treated for alcohol problems have no further symptoms 1 year later.”8 Our Admissions Navigators are available 24/7 to discuss treatment options with you today.

Sources:

[1]. MedlinePlus. (2018). Blood Alcohol Level.

[2]. Centers for Disease Control and Prevention. (2018). Fact Sheets – Alcohol Use and Your Health.

[3]. Dubowski, Kurt. ResearchGate. (2019). Stages of acute alcoholic influence/intoxication blood alcohol concentration grams/100 ml stage of alcoholic influence clinical signs/symptoms.

[4]. Centers for Disease Control and Prevention. (n.d.). Blood Alcohol Concentration.

[5]. National Highway Traffic Safety Administration. (n.d.). Drunk Driving.

[6]. Loyola University Maryland. (n.d.). Calculate Your Blood Alcohol Level.

[7]. National Institute on Alcohol Abuse and Alcoholism. (n.d.). Drinking Levels Defined.

[8]. National Institute on Alcohol Abuse and Alcoholism. (2014). Treatment for Alcohol Problems: Finding and Getting Help.