Sleeping 8 Hours Per Night is a Surprisingly New Concept

Have you ever lain in bed, staring at the clock on your bedside table? 

As you watch the hours tick by, you become increasingly anxious. You find yourself counting backward from the time of your morning alarm, wondering if you can possibly manage to get enough hours of sleep to prepare for a busy day at work or school.

We’ve been conditioned to believe that eight hours of consecutive sleep is a kind of Holy Grail, that magic number that will allow us to feel well-rested and capable of taking on the day.

But it wasn’t always like that.

Researchers have found that our attitudes toward sleep used to be very different. And their discoveries suggest that lying awake in the middle of the night may not be as bad as we think.

It might be normal, natural, and even healthy.

Here’s the history of sleeping eight hours a night and why eight hours of sleep may not necessarily be the golden standard to strive for. 

Photo by Kinga Cichewicz on Unsplash

Is the concept of an eight-hour sleep just a myth?

Back in the 1990s, a psychiatrist named Thomas Wehr performed an experiment in which subjects were deprived of light for 14 hours every day. 

His goal was to track how this affected their sleep patterns. What he discovered is that most subjects ended up sleeping in two distinct four-hour periods, with a one or two-hour period of wakefulness in between these. 

Then in 2001, a historian named Roger Ekirch published findings that revealed that in previous periods in history, it was common practice for people to sleep in two separate cycles. 

He combed through historical records from all over the world and found over 500 references to a “first sleep” and a “second sleep.” 

During the period of wakefulness between the two periods of sleep, people engaged in various activities such as smoking, writing, visiting, or praying.

We even find that prayer books published in the 15th century included specific prayers for the time between periods of sleep.

What did our ancestors do?

So what precisely was the relationship between our ancestors and sleep? A professor of psychiatry named Jerome Siegel aimed to discover exactly that. 

He studied the sleep patterns of several different tribes of indigenous people: the Tsimane people in Bolivia, the Hadza in Tanzania, and the San in Namibia. 

These tribes were mainly hunter-gatherers with lifestyles very similar to our ancient forebears.

Siegel made many interesting discoveries in his research. One was that members of these indigenous tribes commonly stayed awake until about three-and-a-half hours after sundown. 

In the past, we assumed that staying awake past sundown was a modern adaptation to electric lights. But now it seems that staying up a few hours after sundown is a natural human rhythm.

He also made another equally interesting discovery. These indigenous people rarely got a full eight hours of sleep. They were normal to clock in about six hours and 25 minutes of sleep per night.

Why do we sleep?

It’s fair to say that we all look forward to our hours of shuteye. But when did we decide that sleeping regularly was a good idea?

As long as humanity has existed, sleep has been part of our lifestyle, just as much as eating, drinking, or breathing. So it seems obvious that regular patterns of sleep are a necessity. But why?

There are several theories. One is simply that ancient humans slept to conserve energy. If food was scarce, this period of inactivity slowed our metabolism, so we didn’t need to eat as much.

Some people think that the ancient need for sleep goes back to the need for humans to remain quiet and hidden for a certain period of the night to be less vulnerable to predators.

Others point to the brain development that happens to children during sleep as a sign that we need this period of time to increase brain plasticity.

And finally, some believe that sleep functions as a way to restore and repair the body during rest.

When and why was segmented sleep normal?

The historical records uncovered by Roger Erkich show many examples of the normality of segmented sleep as referenced in literature. 

In an Old English ballad called “Old Robin of Portingale,” we find these lines:

At the wakening of your first sleep you shall have a hott drinke made,

And at the wakening of your next sleepe

Your sorrowes will have a slake.

We also find mention of “first sleep” and “second sleep” in multiple languages, including French, Italian, and Latin.

But by the 17th century, things had started to change. People began to associate the nighttime hours with unsavory activities like excessive drinking and prostitution. 

In 1667, Paris began using streetlamps, and other cities soon followed suit, encouraging people of all social classes to use nighttime for productivity rather than quiet reflection and prayer. 

Finally, with the start of the industrial revolution, spending hours lying awake in bed became impractical, as this would have interfered with productivity.

The history of sleep

Based on Jerome Siegel’s research, we now understand that our Neolithic ancestors slept just over six hours a night. 

They did not wake up during the night; however, their sleep patterns seemed influenced by temperature. 

Once people began to migrate north to Europe, a biphasic pattern (two separate phases of sleep) became the norm. 

In ancient Greece and medieval Europe, we find ample records of biphasic sleep. However, by the late 1600s, such references began to taper off, and had completely disappeared by 1920.

Following the Industrial Revolution, the demand for productivity combined with the prevalence of streetlights and electric lighting forced people to compress their sleep into one uninterrupted cycle for efficiency.

In fact, it became so compressed that many people were not even getting six hours, let alone eight. This became one of the many issues cited by labor activists in the 1800s as they advocated for better working conditions.

Today, the human relationship with sleep remains complicated. Many of us struggle to fall asleep or to stay asleep for an entire night. 

Perhaps taking a page out of the book of our forebears, and using wakeful time for reflection, may mitigate the widespread modern problems of insomnia and stress.

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