Forget 8-Hours of Sleep: Find Out the Unusual Way Our Ancestors Slept

Learn How Humans Used to Sleep

ByABC News
November 18, 2015, 4:12 PM

— -- The need for sleep is universal with everyone both young and old needing to get some shut-eye to stay healthy.

With our own Dan Childs, head of the ABC News Medical Unit, undergoing an experiment of staying awake for 40 hours we're re-examining just why we think eight hours of sleep is a good thing. In the past sleeping a solid eight hours wasn’t always the recommended or popular way to recharge.

Before the advent of electricity people often slept in two distinct sections, the first starting shortly after sundown, according to some historians.

After their first sleep they would have “a period of quiet wakefulness and they might not get out of bed or do stuff and then settle into second sleep and would spend the rest of the night [asleep,]” explained Dr. Phillip Gehrman, a sleep expert and assistant professor of Psychiatry at the University of Pennsylvania.”It was broken into two chunks essentially.”

Called bi-phasic sleep, this seemingly odd schedule was according to some scholars a popular way to get sleep for centuries before the modern era. In the industrial age, gas light and later electricity meant there was light even after the sun went down.

A. Roger Ekirch, a professor of history at Virginia Tech Univeristy, who has studied how we used to sleep, said as technology improved our sleep schedule started to change rapidly.

"Until the late 19th early or 20th century with the industrial revolution...the standard pattern of sleep, since time immemorial was segmented or biphasic," he told ABC News.

With the invention of electricity and Thomas Edison’s filament light bulb the need to go to bed with the sun was suddenly irrelevant. People could now stay up late reading, dining or working.

Prior to the industrial revolution people would spend an hour between first and second sleep doing all kinds of activities.

"The range of activities is striking," said Ekirch. "From late middle ages on to 19th century they would stay in bed to meditate and reflect upon dreams. [They had] special prayers."

However, Gehrman pointed out there are still many parts of the world where sleeping a healthy eight hours a night isn’t the norm or even the recommendation. People in countries further sound and closer to the Equator often enjoy a midday nap or siesta, where they avoid the worst of the noon heat.

Dr. Gehrman pointed out that while everyone needs rest there’s few actual evidence pointing out that an eight hour sleep schedule is better than the biphasic sleep or the siesta lifestyle.

“There’s basically no studies to show what happens if you put people on this type of pattern [of altered sleep,]” Gehrman told ABC News.

He points out that many people are outliers who don’t often adhere to sleeping for one long eight-hour block.

“Supposedly Edison one of his motivations to create the lightbulb, he felt we should be able to keep working late into the night,” explained Gehrman.

However, Gehrman said Edison ended up finding ways to still be rested even after long hours in the lab. “He didn’t get a lot of sleep at night,” Gehrman siad. “Apparently after his death [people] reviewed his sleep diaries, he slept 2 long naps a day…. his total sleep was 7 or 8 hours.”