Scientific distinction between natural short sleepers and sleep deprivation

Research indicates that true short sleepers are a rare group of individuals with specific genetic mutations, such as variations in the DEC2 (BHLHE41) gene, which allow them to function optimally on approximately four to six hours of sleep without adverse health effects.

In contrast, many individuals who claim to be short sleepers are actually suffering from chronic sleep deprivation. Scientific studies show that persistent lack of sleep increases the risk of serious health issues, including heart disease, dementia, and premature death, even if the individual feels they have adapted to the deficiency.

Health authorities, including the Ministry of Health, Labour and Welfare in Japan, recommend that adults aim for at least six hours of sleep, while organizations like the American Academy of Sleep Medicine suggest seven or more hours for those aged 18 to 60. There is currently no scientific evidence to suggest that individuals can train themselves to become true genetic short sleepers.