As we’ve been launching The World’s Largest Sleep Study, one interesting fact that keeps coming up is that lack of sleep can impair your brain as much as being intoxicated by alcohol.



How do we know that?

Scientists have confirmed that both sleep deprivation and alcohol can reduce cognitive test scores, so the two states are similar in that way. However, several studies have gone a step further and compared sleep deprivation and intoxication directly.

One clever study by Williamson & Feyer put people in a good news / bad news sort of situation: half of them got to drink, while the other half stayed awake for a long time. Then (unfortunately for the drinkers) the two groups switched places. This allowed the researchers to directly match up sleep deprivation with alcohol intake in the same group of people, determining the number of waking hours needed to reduce a person’s cognition to the same level as they were when drunk.

It took about 18 hours of waking to reach cognitive impairments as severe as significant intoxication (0.1%, which is legally drunk in most places). That’s the equivalent of waking up at 7:00am and staying up until 1:00am, which many of us do frequently.

It shows how important sleep really is, with big ups and downs in your brain’s functioning depending on how much you get, even in everyday situations.