Trošku OT ale súvisí s našim súčasným spánkovým cyklom, ktorý sa zdá že je produktom priemyselnej revolúcie.

We often worry about lying awake in the middle of the night - but it could be good for you. A growing body of evidence from both science and history suggests that the eight-hour sleep may be unnatural.

In the early 1990s, psychiatrist Thomas Wehr conducted an experiment in which a group of people were plunged into darkness for 14 hours every day for a month.

It took some time for their sleep to regulate but by the fourth week the subjects had settled into a very distinct sleeping pattern. They slept first for four hours, then woke for one or two hours before falling into a second four-hour sleep.

Though sleep scientists were impressed by the study, among the general public the idea that we must sleep for eight consecutive hours persists.
http://www.bbc.co.uk/news/magazine-16964783

prevzate aj na sme: http://veda.sme.sk/c/6277333/ludia-kedysi-spavali-na-dvakrat.html