In a recent article for The Atlantic, James Hamblin lays out scientific answers to a bunch of common sleep-related questions.
One such FAQ: “Can I train myself to need less sleep?”
The answer, Hamblin says, is no. Unless you have some superhuman capabilities, you cannot.
Here’s the really interesting thing: You’ll probably feel like the “training” is working — like you’re gradually adapting to getting less rest until you’re able to function just fine. But you’ll be wrong. Your cognitive abilities will likely suffer — meaning you won’t perform at your peak at work or at home.
In one study Hamblin cites, experimenters had participants sleep for either four, six, or eight hours per night for 14 days, or not at all for three days.
Results showed that participants who slept for either six or four hours a day performed considerably worse on cognitive tests than those who slept for eight hours a day. Yet even though their performance eventually became as low as it was for those sleeping only two hours a day, their sleepiness ratings never reached the level of those sleeping only two hours a day.
“People have the subjective impression that they have adapted to [chronic sleep restriction] because they do not feel particularly sleepy,” the authors write.
Another study, which took place around the same time, had participants sleep for three, five, seven, or nine hours a day for one week. Interestingly, among those who slept for five or seven hours a day, cognitive performance declined for a few days, and then stabilised at a level lower than when they started the experiment.
So yes, the brain was adapting to moderate sleep restriction — but the participants still weren’t performing at their peak.
As David Dinges, the chief of the division of sleep and chronobiology at the University of Pennsylvania and a co-author on the first sleep-restriction study mentioned, told Hamblin, you might not be aware of how chronic sleep restriction is affecting you: “You may be cheerful, but not cognitively fit. Or you may be cognitively fit, but hard to be around because you’re pushy or hyperactive.”
The optimal amount of sleep differs for everyone. Most people require between seven and nine hours a night; a small portion of the population can function on much less, while another small portion needs a lot more.
As Business Insider’s Kevin Loria has reported, one way to figure out how much sleep you personally need is to let yourself sleep naturally for about a week. Go to bed when you’re tired and wake up when you’re ready. It’s even better if you limit alcohol and caffeine.
Bottom line: There’s no way to “hack” your body’s sleep needs. Once you’ve determined how much rest you require, try to get it — or know that if you don’t, you probably won’t be your best self.
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