Scientists have revealed the secret of people who get a full night"s rest in just four hours

Scientists from the Weill Institute for Neurosciences at the University of California found that a rare genetic variant of ADRB1 can increase the activity of neurons responsible for wakefulness. This allows a person to sleep four to six hours each night without obvious signs of sleep deprivation. The results of the study were published in the journal Neuron.

The specialists studied in detail a rare mutation in the ADRB1 gene, first discovered in a family where several consecutive generations exhibited unusually short sleep duration. Carriers of this variant could get by their entire lives on approximately six hours of sleep or even less — while feeling completely normal.

Experiments on genetically modified mice demonstrated that the mutation alters the function of the ADRB1 receptor. This receptor is highly expressed in a region of the brainstem associated with wakefulness regulation. In mutation carriers, the corresponding nerve cells are more easily activated and remain more active during waking periods. As a result, the brain switches more quickly from sleep to wakefulness, reducing overall rest duration.

The scientists also tested how widespread this effect is beyond the original family. To do this, they analyzed data from 191,929 individuals for whom genetic and sleep information was available. The ADRB1 mutation was found in 69 unrelated participants. However, they slept an average of 7.1 hours compared to 7.2 hours for carriers of the common gene variant — meaning they were virtually indistinguishable from them.

The researchers believe that the same mutation can manifest differently depending on an individual's other genetic characteristics. Therefore, having the ADRB1 variant alone does not necessarily mean that a person truly needs less sleep.

Notably, ADRB1 is not the only gene associated with naturally short sleep. Previously, scientists discovered variants in the genes DEC2, NPSR1, GRM1, and SIK3. This points to the existence of an entire group of genetic mechanisms capable of influencing sleep duration.

"At the same time, this study does not mean that an ordinary person can safely reduce sleep to four to six hours. This is about a rare hereditary trait, not an ability that can be acquired through training. For most people, lack of sleep remains associated with health risks," the scientists warned.