Not everyone needs to sleep 8 hours - what a new study showed

A new scientific review published in the journal Brain Medicine questions the universality of the rule that everyone needs exactly eight hours of sleep. Researchers analyzed data from anthropology, genomics, and observations of hunter-gatherers, finding that optimal sleep duration is individual and depends on age, health, and circadian rhythms. The review emphasizes the importance not only of duration but also of regularity and bedtime.

A new scientific review published in the journal Brain Medicine questions the universality of the rule that everyone needs exactly eight hours of sleep. The authors examined data from anthropology, history, and comparative genomics, including observations of traditional hunter-gatherer communities whose sleep duration ranged from 6.4 to 7.1 hours. The researchers do not propose a new universal norm but indicate that sleep needs are individual and depend on age, health, and biological characteristics. The review emphasizes that sleep must be assessed comprehensively: not only hours matter, but also regularity of schedule, bedtime, and alignment with circadian rhythms. One study involving 770 healthy young adults identified five different sleep profiles. Another large study based on the UK Biobank (88,461 participants) found a link between sleep characteristics and 172 diseases, with many connections driven more by regularity than total duration. The authors note that the data do not prove a direct causal relationship. The review does not overturn existing CDC recommendations (7–9 hours for adults) but questions the notion that absolutely everyone must sleep exactly eight hours.