Why most people need eight hours of sleep while rare short sleepers thrive

Catia Reis of the University of Lisbon says most people cannot accurately assess their own sleepiness, which often results in hidden sleep debt and increased health risks. Ying-Hui Fu from the University of California San Francisco stresses that sleep deprivation is tied to virtually every brain disease and can be lethal within weeks. While most adults need roughly 7.5 to 8.5 hours nightly, a rare group of natural short sleepers possess genetic variants—such as DEC2, ADRB1, NPSR1, GRM1 and SIK3—that allow them to thrive on under six hours.

Research on these genes suggests they affect sleep regulation, cardiac signaling, arousal, mood and cellular metabolism. The piece also references Prime Minister Sanae Takaichi of Japan, who publicly claims to survive on zero to three hours of sleep, illustrating the contrast between voluntary sleep restriction and the genetic exception. Scientists caution that more longitudinal studies and funding are needed to fully understand short-sleep genetics and their potential health benefits.