Alcohol – Blackouts, Brownouts and how they affect your body

Do you remember what you did last night? Have you ever not remembered what you did after drinking? Drinking alcohol affects the brain and can cause lasting damage including, but not limited to, slips in memory. These memory slips can be due to lack of blood flow to brain areas that are important for memory consolidation and are commonly known as blackouts. Contrary to what popular belief, blackouts often occur in social drinkers and don’t seem to be related to age or level of alcohol dependence.


Blackouts and the Blood Alcohol Content (BAC) rate

Amnesia, or memory dysfunction, can begin to occur even with as few as one or two drinks containing alcohol. However, as the amount of alcohol intake increases so does the probability of memory impairment. Although heavy drinking alone will not always cause blackouts, heavy drinking of alcohol on an empty stomach or “chugging” alcoholic drinks often does cause blackouts.

The estimated BAC (blood alcohol content) range for blackouts begins at levels .14%- .20%. Individuals who reached high BAC levels slowly experienced far less common occurrences of blackouts. Additionally, while blackouts lead to forgetting entire events that happened while intoxicated, some individuals experience an inability to recall only parts of an event or episode (these are often called brownouts).

Blackouts can occur to anyone who drinks too much too fast. In a survey of college students, males and females experienced an equal number of blackouts, although men consumed a significantly more alcohol.

Although brain damage could potentially occur from heavy alcohol consumption, there is no evidence that blackouts are caused by brain damage per se. However, if brain damage is caused from excessive alcohol use, some studies show improvements in brain function with as little as a year of abstinence. Regardless of the possibility of reversing any effects, alcohol use causes damage in different areas of the body (including the liver), and those damages have been shown to occur more quickly among females.

Co-authored by Jamie Felzer



1. White, Aaron M., Signer, Matthew L., Kraus, Courtney L. and Swartzwelder, H. Scott(2004). Experiential Aspects of Alcohol-Induced Blackouts Among College Students, The American Journal of Drug and Alcohol Abuse,30:1,205 — 224

2. Alcohol Alert (2004) . Alcoholic Brain Damage. Alcohol Research & Health, Vol. 27.

2 responses to “Alcohol – Blackouts, Brownouts and how they affect your body”

  1. I saw your link on Facebook & clicked on it. This article on blackouts was very informative. I look forward to looking at more of your website. I was a “late-in-life” alcoholic, and have been sober for about 2 1/2 years. I now work at a rehab facility in the Outpatient area, and am so thankful to be giving back. Thank you for your information.

  2. I recently had a big night out, where I drank for possibly 14 hours straight…It all caught up on me and I passed out in the motel room for around 6 hours and was not contactable (which was not recieved well by my girlfriend)I then finally went home and slept for about 2hours, waking to get a drink I then blacked out and smashed my face on the wall…family was terrified and so was I! I believe I was unconscious for a small amount of time, then went back to bed and also worked all day, headaches all the while! I realise that this is largely due to too much alcohol, lack of sleep and limited food and fluid intake…are there any other reasons as to why this happens and should I consider possibly getting a CT scan or something?

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