Alcohol Info

Alcohol Info

Blood Alcohol Concentration


Blood Alcohol Concentration (BAC) refers to the percent of alcohol (ethyl alcohol or ethanol) in a person's bloodstream.

A BAC of .10% means that an individual's blood supply contains one part alcohol for every 1000 parts blood.

Factors that influence BAC include:

  • the amount of alcohol a drinker consumes
  • the rate at which a person drinks
  • the drinker’s weight and body mass
  • the amount of blood that is mixing with the alcohol
  • gender - women have less of the enzyme that metabolizes alcohol in their stomachs, on average they weigh less and they have less blood volume than men do, even at equal weight.
  • the amount of food in the stomach - a full stomach slows the pace at which alcohol is absorbed. However, eating before drinking will not prevent high BAC’s from occurring.
  • To calculate your estimated BAC:

Alcohol is a Biphasic Drug

What does this mean?

Alcohol produces two different effects based on dose.

BAC of .055% or less: People tend to feel a "buzz", euphoria, and stimulant effects.

BAC above a .055%: The depressant effects of alcohol kick in - which may result in slurred speech, impairment, loss of memory, sickness, etc.

The Point of Diminishing Returns (BAC of .055) is the point at which drinking more will NOT make you feel better, and will only make you more impaired.

Biphasic Graph


Key Takeaway


The desirable effects of alcohol tend to occur in low doses, and the risk of experiencing the undesirable effects of alcohol increases as BAC rises. Lower Risk Drinking Strategies At AODS, we strive to empower students to make their own choices about alcohol - we focus on safety by reducing risk. Below are strategies that may help students to enjoy alcohol while minimizing the risk of experiencing negative consequences.

If you choose to drink, consider using these lower-risk drinking strategies:

  • Eat before and while drinking
  • Set a drinking limit near a BAC of .05
  • Keep track of how much you drink by counting “standard drinks”
  • Space drinks over time
  • Alternate alcoholic beverages and drinks without alcohol
  • Mix and measure your own drinks when consuming mixed drinks
  • Avoid or limit shots of hard alcohol
  • Avoid mixing alcohol with energy drinks
  • Avoid drinking games



It is important to factor in tolerance if you are planning to drink.

What is it?


After several drinking occasions, consumption of a constant amount of alcohol produces a lesser effect or increasing amounts of alcohol are necessary to produce the same effect.

BAC is not affected by tolerance. A drinker with a high tolerance may not feel as impaired as they actually are, despite having a high BAC.

What happens to tolerance after taking a break from drinking?


Your tolerance will decrease and the effects of alcohol may hit you more quickly than you expect.

If you have decreased your alcohol use during the pandemic, please be aware that you may be impacted by alcohol after fewer drinks.