> In Greece remnants of these old ways of rest can still be found in the Summer siesta and "quiet hours" where the workday is split in two by a few hours of rest. Practiced religiously and an unshakeable part of its culture, it is the norm for businesses to open at 9AM, close at 2PM, reopen again at 5PM and close again around 10PM. This second work period is what the Greeks call the "afternoon".

Researchers who lived in African tribes that are _really_ following the "old ways" found that tribespeople followed all kinds of sleep schedules. Somebody was up at almost _all_ times, including the middle of the night.

This makes total sense: you want at least somebody to be awake at all times to raise the alarm if a pride of lions happens to wander close by.

By doing the "split day" you just switch to another fixed pattern.