Text written in Basque and translated automatically by Elia without any subsequent editing. SEE ORIGINAL

Man did not sleep any more before the Industrial Revolution

Today, populations with hunter-gatherer lifestyles sleep between 6.4 and 7.1 hours per night.

Today’s hunter-gatherer populations sleep no longer than in industrialized societies. One review suggests that industrialization, rather than the duration of sleep, changed the time of sleep.

The saying goes that you have to sleep 8 hours a day. But, curiously, this idea was born at the time of the Scottish Industrial Revolution under the motto spread by entrepreneurs: "Eight hours of work, eight hours of rest, eight hours of sleep." Over time, this slogan has become a health standard.

A review published in the journal Brain Medicine sought to find out whether sleeping less has been done since the Industrial Revolution. Combining anthropological fieldwork, archival history and comparative genomics, the results show that the main difference between industrial and pre-industrial sleep is when and how many times a day it sleeps and not how many hours it lasts.

“The number of hours of sleep is the variable that has changed the least.”

To make the comparison, three populations have been selected that currently have a hunter-gatherer lifestyle: Hadza populations in Tanzania, San in Namibia and Tsimane populations in Bolivia. Its inhabitants do not use electric light and their sleep coincides with the natural cycle of light and darkness. The results indicate that these people sleep between 6.4 and 7.1 hours per night. These figures are not higher than the average of industrialized societies, in some cases even lower.

According to the authors, the change in sleep can be summarized in four characteristics: it has been delayed, it has lost its routine, its relationship with light has been weakened and sleep disorders have become more frequent. The variable that has changed the least is the number of hours of sleep.

On the other hand, the study has not found fractional or biphasic sleep patterns in the three populations mentioned. Although it was a well-established belief that pre-industrial Europeans fractionated their sleep in two periods, one or two hours apart, researchers have found no evidence of this. Therefore, the general conclusion is that all the patterns that the dream has had and has had reflect the ecology of light in the place, the climate, work and social life.