Fatigue, trouble paying attention, and general over-excitement are typical symptoms of insufficient sleep, which for most people means less than seven or eight hours a night. But for natural short sleepers, that’s not a problem at all, as they’re genetically wired to get by on less sleep than the rest of us.
These lucky individuals, who do well on six hours of sleep or less, make up about one percent of the population, and researchers are trying to figure out what explains their unique trait. One day, this scientific work could even lead to treatments that could help combat the effects of sleep deprivation.
Ying-Hui Fu, a professor at the University of California School of Medicine at San Francisco, studies the genetics and other characteristics of short sleepers in her neurogenetics lab.
Currently, Fu knows of three types of genetic mutations related to the ability to function well with minimal amounts of sleep, which often runs in families. In a 2009 article published in the journal Science, she described a mother and daughter who had the same genetic mutation in the DEC2 gene that allowed them to thrive on six hours of sleep a night. So far, Fu has identified about 50 short sleeper families.
“This group of short sleepers is unique,” Fu said, describing them as upbeat and energetic, often with more than one job.
One of Fu’s study participants, a woman in her 90s, volunteers at a prison because she has so much time and energy that she feels compelled to use it somehow, Fu said, adding that another female short sleeper in in the 80s often complains that she can’t find a man who keeps up with her.
While researchers say genetics appear to play a key role in short sleepers’ reduced need for sleep, there are still a number of unanswered questions.
“We don’t understand why they’re so optimistic and outgoing when they’re supposed to be apathetic and irritable,” on so little sleep, recruits Dr. Christopher R. Jones, a professor in the University of Utah’s Department of Neurology, briefly a sleeper for scientific studies, told CBS News.
The link between little sleep and full energy isn’t entirely clear to researchers, but mood, temperament and people’s sleep patterns in general are often linked, Fu said.
Interestingly, these high energy levels typical of short sleepers can sometimes reach behavioral extremes. For example, in a 2001 study published in the Journal of Sleep Research that examined the sleep patterns and personalities of 12 short sleepers, researchers found some evidence of subclinical hypomania — a milder form of manic behavior characterized by euphoria, disinhibition, and indeed, a decreased need for sleep.
“That’s our experience, too,” Jones said, describing the short sleepers he’s met as “behaviour-activated.” There might be something about this behavioral activation that helps short sleepers overcome sleepiness, he speculated.
Jones said many researchers believe that short sleepers are actually sleep deprived, but somehow don’t feel the symptoms of sleep deprivation the way most people do. The same Journal of Sleep Research study that showed evidence of hypomania also suggested that short sleepers get about half as many minutes of REM sleep — the stage in the sleep cycle where dreaming occurs — as late sleepers.
Experts stress that it’s important to distinguish between true short sleepers and people who need eight hours of sleep but force themselves to get by on less, which is far more common.
“I’ve never met a true short sleeper,” said Dr. Charles Bae, a sleep specialist at the Cleveland Clinic, told CBS News. “Most people who say they don’t need much sleep don’t have this gene and they’re just kidding themselves.”
Additionally, for normal people, reducing sleep is never a good idea. Previous research has shown that a lack of sleep, which your body needs, can have negative consequences for your health. Sleep deprivation can impair cognitive function and cardiovascular health and increase cancer risk, Fu said, stressing that people should aim to get the amount of sleep they know they need.
Research has even shown that people who don’t get enough sleep have a higher overall risk of premature death, but that doesn’t seem to apply to these natural short sleepers, experts say.
The researchers hope that one day, if they can figure out the mechanism and genetic pathways responsible for the short sleep trait, it could lead to a drug that could potentially reduce the amount that ordinary people need. At this point, however, Fu thinks that’s a fairly distant prospect. “Anything is possible,” she said. “It’s just a matter of how long it takes.”
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