People who naturally sleep less seem to feel better when they sleep less than the rest of the population. (Photo credit: Maria Korneeva via Getty Images)
Some lucky people have rare genetic changes that allow them to function perfectly on just four hours of sleep, while others need around eight hours to function properly.
Researchers recently discovered one such mutation, called SIK3-N783Y, in a human super sleeper. The team then studied the mutation in genetically modified mice and found that mice with the mutation also slept less, according to the new study.
The new mutation is one of several that researchers have linked to shortened periods of sleep. Scientists hope that by studying the genetics of people who are naturally short sleepers and seem to thrive on less sleep, they can offer better treatments for sleep disorders.
“Our bodies continue to function while we sleep,” detoxifying themselves and repairing damage, study co-author Ying-Hui Fu, a neuroscientist and geneticist at the University of California, San Francisco, told Nature. “These people [who are naturally short sleepers], all the functions that our bodies do when we sleep, they can just do at a higher level than we can.”
The results of the study were published Monday (May 5) in the journal PNAS.
There are many negative effects associated with lack of sleep, from feeling tired and more forgetful to an increased risk of heart disease. The amount of sleep needed varies with age, but most adults need about seven to nine hours each night to stay healthy. However, those who naturally sleep less seem to cope just fine with less sleep.
Short sleepers naturally need about four to six hours of sleep per night. Not only do they thrive on less sleep than the rest of the population, but they also tend to feel worse when they sleep longer than normal, according to the study.
Previous studies have identified four genes associated with short sleep and five corresponding mutations in those genes. The newly discovered mutation affects a fifth gene, Sik3, which has previously been associated with sleepiness. The researchers tested the mutation by introducing it into lab mice. They found that mice with the mutation slept about 31 minutes less than mice without it, and 54 minutes less after a period of sleep deprivation, which the researchers induced by gently handling the mice, according to the study.
Mice typically sleep about 12 hours a day, significantly longer than humans, so the new sleep reduction associated with the mutation is 54 minutes less than what is seen in humans with naturally short sleep patterns. The researchers noted that this could be because mice typically have more fragmented sleep than humans, or a result of inbreeding in their mouse strain.
Researchers have much to learn about the genetics of people who naturally sleep less and their nocturnal superpower. The new findings highlight Sik3 as a promising therapeutic target for researchers looking to improve sleep quality and satisfaction, according to the study.
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