Most of us are told that 7 to 9 hours of sleep each night is essential for good health. Lack of sleep, over time, is linked to serious health problems like heart disease, diabetes, obesity, and depression. However, not everyone seems to need that much rest. Some people, known as “natural short sleepers” (NSS), function perfectly well on just 4 to 6 hours of sleep per night.
Surprisingly, sleeping longer than that can even make them feel worse. Scientists have now found a possible explanation for this rare ability, tracing it back to a mutation in a gene called salt-induced kinase 3 (SIK3).
The new study, published in Proceedings of the National Academy of Sciences, identifies a specific mutation in the SIK3 gene, called N783Y, that may be responsible for the short sleep pattern. This gene is crucial for regulating how long and how deeply we sleep.
While our bodies seem quiet during sleep, a lot is actually happening: cells repair themselves, essential hormones are replenished, and neural connections are reorganized. This is why lack of sleep typically results in poor physical and mental performance.
Natural short sleepers, however, seem to bypass these negative effects even with far fewer hours of sleep. Previous studies have found five mutations in four different genes—DEC2, ADRB1, NPSR1, and GRM1—that are linked to this ability. These genetic changes seem to allow them to get the benefits of rest much faster than the average person.
To dig deeper into this phenomenon, researchers recruited a 70-year-old woman who has been a natural short sleeper her entire life. Despite being very active, she reported sleeping just 3 hours per night.
However, when her sleep was monitored with a wrist device called an actigraph, it showed she actually slept about 6.3 hours on average each night. While this was more than she thought, it was still much less than the typical 7–9 hours recommended for adults.
To find the cause, researchers analyzed her DNA using a method called whole-exome sequencing. This process looks at all the genes that code for proteins in the body, hunting for any unusual changes.
They found that she had a mutation in the SIK3 gene. To understand its effect, the scientists created mice with the same genetic change. These mice ended up sleeping 30 minutes less than regular mice, supporting the idea that this mutation really does shorten sleep duration.
To understand why this happens, the researchers performed computer analysis on the SIK3 protein’s structure. The mutation changed how the protein folds and interacts with other molecules, reducing its ability to perform its normal role.
SIK3 is part of a group of enzymes called protein kinases, which help regulate many processes in the body by adding phosphate groups to other proteins. This chemical change is important for signaling within cells, and when it is disrupted, sleep patterns are affected.
The study not only confirms the link between SIK3 and natural short sleep but also opens up new possibilities for treating sleep disorders. If scientists can better understand how this mutation allows people to stay healthy on less sleep, it might be possible to design treatments that improve sleep quality for those who struggle with insomnia or other sleep problems.
The researchers suggest that targeting the SIK3 pathway could help those who suffer from sleep deprivation by making sleep more effective and restorative.
This discovery adds to the growing understanding of how genetics can influence sleep habits. It shows that some people are biologically wired to need less sleep without the usual health risks that come with sleep loss. Moving forward, researchers hope to explore how these findings can be applied to improve sleep therapies, making restful sleep more accessible for everyone.
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The research findings can be found in PNAS.
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