The popular myth about mandatory sleep time has been debunked

The widespread belief that exactly eight hours of sleep per night is necessary for good health lacks unequivocal scientific confirmation. This is the conclusion reached by researchers who studied the sleep patterns of modern hunter-gatherer societies. It turned out that their nighttime rest duration is comparable to that of residents of industrialized countries, and sometimes even falls short of it. The review was published in the journal Brain Medicine.

As reported by TUT.AZ, field observations of three hunter-gatherer communities revealed an unexpected picture: people in these groups sleep an average of 6.4 to 7.1 hours per night — no more, and sometimes even less, than residents of large cities. Scientists believe that industrialization has changed the time of falling asleep and the regularity of sleep schedules to a greater extent than the actual duration of nighttime rest.

The popular hypothesis of so-called segmented sleep has also been called into question. Its proponents claim that in the past, people regularly divided their nighttime rest into two separate periods. However, the review's authors point out that references to "first sleep" in historical documents could have carried a wide variety of meanings and do not in themselves prove the existence of a universal biphasic sleep pattern.

The phenomenon of healthy "short sleepers" deserves special attention. Carriers of a rare variant of the DEC2 gene are able to function fully on significantly less sleep. This suggests that short sleep is far from always a sign of a disorder or sleep deficit.

At the same time, the researchers emphasize that sleep quality is largely determined by social conditions. Urban noise, artificial lighting, high temperatures, and poor housing conditions hit the nighttime rest of residents in disadvantaged neighborhoods particularly hard.

The main conclusion of the review's authors is as follows: rather than chasing the magic number of eight hours, it is far more important to maintain a regular schedule and ensure its alignment with the natural light cycle. At the same time, the scientists acknowledge that reliable experimental studies directly comparing segmented and continuous sleep under identical conditions remain critically scarce.