Many of us have stayed up all night to meet a deadline or squeeze in one more night out, but researchers say even a single sleepless night can come with real health consequences.
In the U.S., adults are generally advised to aim for around seven to nine hours of sleep per night to support overall health and mental performance.
Realistically, though, day-to-day life doesn’t always make that easy, and plenty of people end up running on less sleep than they should.
Still, it may be worth thinking twice before making all-nighters a habit. Scientists have linked just one night without sleep to a range of brain changes that resemble issues seen in Alzheimer’s disease.
And if the goal is better exam performance, the evidence suggests staying up all night may backfire rather than help.
According to reporting in the Daily Mail, researchers at the University of Ibadan in Nigeria examined a large body of medical research published over the past 25 years, focusing on sleep deprivation, memory, and brain function.
Their review described troubling short-term effects from missing sleep, including impaired memory and weaker connections between brain cells.
The team also noted that even brief sleep loss may interfere with the brain’s ability to generate new cells, while allowing harmful waste products to accumulate.
These effects were compared to changes associated with Alzheimer’s, a progressive neurodegenerative disease and the leading cause of dementia in the U.S.
The National Institute of Aging reports that Alzheimer’s is responsible for between 60% and 80% of dementia cases nationwide.
There is some reassurance, however: the researchers suggested the problems triggered by lost sleep can improve when people catch up on rest, including through naps and additional sleep.
The review also raised another point for students and anyone cramming for a big test: all-nighters don’t necessarily boost learning. Rather than locking in information, sleep deprivation was linked to increased forgetfulness, along with poorer decision-making and a worse mood—hardly ideal for important exams.
One night is one thing—but what happens when someone stays awake for an extreme stretch, like 264 hours?
In 1963, 17-year-old Randy Gardner and his friends set out to find out, and Gardner volunteered to remain awake for as long as possible. The attempt ultimately stretched to 11 days without sleep.
Afterward, he was taken to a hospital where doctors monitored his brain activity. Although they described him as “medically healthy” at the time, Gardner later said he felt the effects long after the experiment ended.
Decades later, in 1997—more than 40 years on—he reportedly became unable to sleep, though the precise cause was never made clear.