For being rested, most adults need at least six hours of sleep. In case they sleep less than six hours for a longer period of time physical and/or mental problems might be the consequence(s).
But, why are there people who only need about five hours of sleep for being rested and concentrated? A group of scientists around Renata Pellegrino of the Children’s Hospital, Philadelphia, conducted a study. Here, they found out that a gene alteration is responsible for this.
100 fraternal twins were examined and their natural need to sleep was tested. It was detected that test-persons with a change in the gene BHLHE41 slept five hours, on an average. The twin without the genetic change needed more than an hour more.
The participants were not allowed to sleep for 38 hours. Subsequently, attention- and perception-tests were conducted. The persons with the gene-mutation made 40 % less mistakes than their twin. Furthermore, the recovery phase after sleep deprivation was shorter. They only needed eight hours of sleep whereas the respective twin needed 9.5 hours to feel recovered again.
The scientists assume that short-sleepers more effectively use recovery periods. The duration of deep sleep phases was the same in both groups. But, the REM-phase in which our body is very active was shorter with the short-sleepers.
It was possible, to prove the connection of the change of the gene BHLHE41 and sleep duration in a second study. This study was conducted by the Department of Neurology of the University of California, San Francisco. Here, families with short-sleepers were tested and different changes of the gene BHLHE41 were detected.
This leads to the conclusion that the need of sleep doesn’t depend on personal preferences but is biologically determined.
Image Source: ©istock
This post is also available in / Diesen Beitrag gibt es auch in: German
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