Key Takeaways

  • The liver processes one standard drink per hour - nothing speeds this up
  • Empty stomach = faster absorption; food = slower absorption
  • BAC of 0.08% is the legal driving limit in all US states
  • Carbonated mixers and warm drinks speed absorption
  • Women typically have higher BAC than men with the same consumption
Last updated: January 2026

1.2 How Alcohol Affects the Body

Understanding how alcohol is absorbed and metabolized helps you recognize intoxication and understand why people become impaired at different rates.

Alcohol Absorption

Where alcohol is absorbed:

  • 20% in the stomach
  • 80% in the small intestine

Time to feel effects: 15-45 minutes after drinking

Peak BAC: Usually reached 30-90 minutes after last drink

Factors That SPEED UP Absorption

FactorWhy It Matters
Empty stomachNo food to slow absorption
Carbonated mixersCO2 increases absorption rate
Warm drinksAbsorbed faster than cold
Stronger drinksHigher concentration = faster absorption
Drinking quicklyMore alcohol enters system at once

Factors That SLOW DOWN Absorption

FactorWhy It Matters
Food in stomachEspecially fatty, protein-rich foods
Water consumptionDilutes alcohol in stomach
Drinking slowlyAllows body time to metabolize

The Liver and Metabolism

The liver processes alcohol at a constant rate:

  • Approximately one standard drink per hour
  • This rate cannot be sped up by coffee, food, or exercise
  • BAC rises if drinking faster than one drink per hour

Blood Alcohol Concentration (BAC)

BAC measures the percentage of alcohol in your bloodstream.

BAC LevelTypical Effects
0.02-0.03%Mild relaxation, slight mood changes
0.04-0.06%Relaxation, lowered inhibitions, impaired judgment
0.07-0.09%Impaired balance, speech, reaction time
0.10-0.12%Significant impairment, slurred speech
0.15%+Major impairment, vomiting possible
0.30%+Loss of consciousness possible
0.40%+Potentially fatal

Legal driving limit in all US states: 0.08% BAC

Factors Affecting BAC

Physical Factors:

  • Body weight - Larger people have lower BAC
  • Body fat - Higher fat = higher BAC (fat doesn't absorb alcohol)
  • Sex - Women typically have higher BAC than men with same consumption
  • Age - Older adults process alcohol more slowly

For the Exam: Remember that the liver processes about one standard drink per hour, and nothing can speed this up.

Test Your Knowledge

How quickly does the liver process alcohol?

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Test Your Knowledge

Which factor will cause alcohol to be absorbed MORE QUICKLY?

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Test Your Knowledge

What is the legal BAC limit for driving in all US states?

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Test Your Knowledge

Can drinking coffee or taking a cold shower sober someone up?

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