Skip to main content

Secondary navigation:

Passing Out from Alcohol Consumption

definition, suspected causes, and associated dangers


“Passing out” is a colloquial term for syncope, which describes a loss of consciousness. Passing out is not uncommon across the life span, but passing out from alcohol use is very dangerous.

What Defines Passing Out from Alcohol Use?
  • Passing out from alcohol means that the person loses consciousness.
  • It could look like someone who suddenly loses consciousness after drinking.
  • It could look like someone who is sleeping and, as they slip into unconsciousness, they are unable to be woken up.
  • Alcohol use leading to passing out could also lead to breathing less than 8 times per minute, uncontrollable vomiting, bluish or pale skin, confusion, seizures, or uneven breathing.

Suspected Causes

  • Alcohol lowers blood pressure. If someone is sober, their body constricts their veins upon standing up so as to increase blood pressure and prevent the person from passing out as their blood falls due to gravity. Even with low-risk drinking (2-3 drinks per occasion), alcohol prevents the blood vessels from constricting, and blood pressure drops twice as much when the person stands up as it would if they were sober.
  • Alcohol is a diuretic, and causes your body to dehydrate.
  • Alcohol also lowers your body temperature, and can cause you to become hypothermic.
  • Alcohol can also cause hypoglycemia, which can cause a coma.

Associated Dangers

  • A person can move from sleeping to unconsciousness without others noticing. This is the danger in allowing someone with alcohol poisoning to “sleep it off.”
  • Taking a cold shower, which is an ineffective technique often used to “sober up,” can actually cause a person with alcohol poisoning to lose consciousness due to the decrease in body temperature.
  • Alcohol also inhibits the gag reflex, which can cause a person who is unconscious to aspirate their own vomit, causing death.
  • Drinking enough alcohol to reach the point of passing out can happen very quickly, especially when drinking shots. This means that a person can drink enough to cause them to pass out, but not pass out for a while longer (and therefore, possibly continue to drink) due to the time the body needs to process alcohol.
    • Drinking to the point of passing out happens much faster when the person has not eaten. On an empty stomach, 20% of alcohol is absorbed directly from the stomach and reaches the brain in less than 60 seconds.