Sleeping the full eight hours usually advised by doctors might not be necessary for everybody, according to a new study, which suggested there’s a gene that dictates how much sleep a person needs.
Aresearching team at the University of California, headed by Ying-Hui Fu, analyzedthe genes of 12 members of a family that sleeps as little as 4.5 hours pernight without feeling tired. They found they had a mutation in a gene calledADRB1.
“We all spend about one-third of our lives in the state of sleep,” Fu said. “In fact, considering how important sleep is to our well-being, it’s astonishing that we know so little about how sleep is regulated.”
The team bredrats with the same mutation, which slept about 55 minutes less per day. Thiscorrelated with altered activity in a brain region called the dorsal pons thatis known to regulate sleep.
In normalrats, ADRB1-expressing brain cells were found to be inactive during most sleepstages, but active when they were awake. In the mutant ones, these cells wereeven more active during waking hours. The researchers also found they couldwake up sleeping rats by artificially activating these ADRB1-expressing braincells.
The results suggest that ADRB1-expressing brain cells promote wakefulness and that variations in the ADRB1 gene influence how long we can stay awake for each day, said Fu. Her team has previously found that mutations in other genes like DEC2 also make people need to sleep less.
These mutations don’t seem to be associated with any negative health consequences. “Most natural short sleepers are very happy about their sleep pattern – they usually fully take advantage of their extra time,” Fu told New Scientist.
Theresearchers think the ADRB1 and DEC2 mutations must have emerged recently inhuman history and haven’t had time to spread widely yet. “The 8-hour norm hasbeen the standard for a long time, but somehow a few new mutations occurredrecently and produced this seemingly advantageous trait,” Fud said.
While thisis newly discovered mutated gene contributes to short sleep, the studyhighlighted it’s probably not the only one. There are likely more unrecognizedgenes and regions of the brain that tell our bodies when to go to bed and risein the morning.
“Identifying genes, and mutations, that cause people to sleep less naturally without significant negative impact lays the groundwork for scientists to investigate how our sleep homeostasis and efficiency is regulated at the molecular and neuronal levels,” Fu says.
