There’s a rare breed of human that can function on just a few hours of sleep each night. They’re called “super sleepers.” Because, supposedly, less than 7 to 9 hours of sleep doesn’t leave them groggy or pounding coffees to lift the fog of exhaustion. But new research suggests these people might be more tired than they realize, the consequences of which can bleed into other aspects of life and health.
In the study, published in the journal Brain and Behavior, researchers scanned the brains of 839 people while they were awake. The men and women were split into two groups: One that reported sleeping between 7 and 12 hours each night in the past month, approximately; and another that slept 6 hours or less per night in the past month, on average. Then, researchers divided the short-sleeping group into people who said they felt too tired to function normally during the day and those who said they felt fine despite getting very little sleep on a regular basis.
The brain scans showed that most people who slept 6 hours or less per night had brain patterns normally seen during sleep, the researchers say. So super sleepers who reported being funtional even after small amounts of sleep might have actually drifted off while having their brains scanned.
“People are notoriously poor at knowing whether they’ve fallen asleep for a minute or two,” study co-author Jeff Anderson said in a statement.
What’s more, the researchers think the reason super sleepers fell asleep during the experiment is not just that they were tired, but because they were bored. Their attention wasn’t being stimulated during the brain scan. Super sleepers tend to seek out constant stimulation, which may help them “override the need for sleep,” study co-author Paula Williams told Live Science. “But there is evidence that if you take away stimulation, they are still showing the signs of sleep deprivation.”
Some consequences and side effects of sleep deprivation include moodiness, weakened immune response, weight gain, and greater incidence of accidents. (Read: 3 (More) Reasons Why Sleep Deprivation Is Hurting Your Body.) Even if you’re falling asleep for a minute or two, that’s a minute or two more than what’s acceptable in a business meeting. Struggling to fall asleep at night? Read: