March 12, 2019

Biphasic Sleep: Naturally Preferred

biphasic sleep edisonDid you know that sleeping in one consecutive chunk of time isn’t naturally how we operate. Even now days, if left with nothing but the natural sunlight we would fall back into a state of biphasic sleeping. So why have we evolved into a less natural monophasic sleeping pattern?

I’ll tell you – that darn Thomas Edison and his lightbulb have officially ruined your sleep. Well, that might be a bit dramatic, but taking a look back in time you can see how our sleep has changed with the times.

When Night Was Truly Dark

You probably don’t know real darkness. It began to disappear less than two centuries ago when gas light. And then electric light, erased darkness and changed our world – and our sleep. And it is only in the last two decades that the history of sleep, including the effect of artificial light on sleep, became a subject of serious scholarship.

biphasic sleeping skyglowUnless you live many miles from the reflected electric light aura (skyglow) over a town – even a small town – it is difficult to comprehend the outdoor darkness that surrounded us before electricity. In Colonial America, a cloudy night made outdoors impenetrably dark – “hand in front of your face” dark. People couldn’t see to move around outdoors, and they couldn’t see outdoor danger.

Consequently, they stayed inside at night, just as most humans had for thousands of years. Now, very few Americans – and even fewer Europeans – experience that earlier total darkness. More than 99% of us live where there is measurable skyglow. Thus lighting our surroundings, at least to some degree. Thanks to Edison, the skyglow from Las Vegas is visible in Death Valley, 100 miles away. It is part of what we now consider “light pollution.”

….and Indoors Was Almost as Dark

sleeping by fireFor Colonial Americans, and all their ancestors, back to the earliest recorded civilizations, indoor space was (at best) poorly lit at night. The interior of a Colonial Period cabin or home might have had some illumination from oil lamps or candles. But even those were too expensive for regular use by poorer classes.

We all know the story of Abraham Lincoln, studying only by the light from his cabin fireplace. That inadequate, or non-existent, indoor light meant that Americans, along with most other people of that time, retired to bed after sunset. But we now know they spent those bedtime hours quite differently than we do today.

Biphasic Sleep

at days closeAs earlier mentioned, it is only in recent years that the history of sleep became a subject of study. A remarkably tardy development considering humans spend a third of their lives in bed. A. Roger Ekirch, author of At Day’s Close: A History of Nighttime, was one of the first to make sleep history an academic pursuit. He is widely considered to be the foremost scholar in the field. His pioneering work established that our modern sleep patterns are not those of our ancestors – even our relatively recent ancestors.

“Humans slept twice,” Ekirch says. “a deeper first sleep from sunset until around 2am. Followed by an interval of wakefulness, usually lasting an hour or two. Then a lighter second sleep until around 6am, or later in the winter.”

Ekirch found more than 500 historical written references to “first sleep” and “second sleep,” ranging from Chaucer through the 18th Century. A 16th Century French doctor’s manual counseled that the best time to conceive was “after the first sleep” when the couple would have “more enjoyment” and “do it better.” Other wakeful period activities included talking, eating, praying, and even raiding the neighbor’s woodpile.

According to Ekirch, it was the advent of indoor electric lighting that nudged us into the idea that we are designed to sleep straight through the night, rather follow thousands of years of our natural biphasic pattern.

Biphasic Sleep Not Forgotten

biphasic sleepAn experiment by psychiatrist Thomas Wehr, a researcher at the National institute of Mental Health (NIMH), supports Ekirch’s conclusions. Wehr’s subjects spent a month in 14 hour a day darkness. They could sleep whenever they liked.

By the end of the experiment they’d settled into a daily pattern of sleeping three to five hours. Then waking for one to two hours, and then going back to sleep for another three to five hours. The experiment seems strong evidence that biphasic sleep is our natural preference. It just doesn’t work all that well in our modern world.

The End of Biphasic Sleep – A Mixed Blessing

nightime activityBeginning in the early 1800s nighttime outdoor activity was encouraged by gas streetlights. And by the late 1800’s indoor gas and electric lighting enabled us to remain active indoors after dark. Evenings of socializing with family and neighbors became possible. Manufacturers began scheduling workers for shift work and children could do schoolwork.

Many chores not easily be done by candlelight or fireplace light became. Sewing a patch on a garment, for instance, was much better done under a lightbulb. All these options encouraged people to remain awake during the first hours of evening darkness. The consequence was the “phasing out” of biphasic sleep.

Monophasic Sleep – The Consequences

The price we paid for those lighting advances was the exchange of natural biphasic sleep for “consolidated sleep.” Seven or eight hours of sleep intended to be continuous, and without interruption. We’d added hours of early evening activity at the cost of the time we once allocated to middle of the night wakefulness.

too much sleep 7Unfortunately, most adults are not naturally wired to sleep straight through for seven or eight hours. Some can manage the skill (though very few in the over-40 crowd). The rest of us tend to wake up in the night. Now that biphasic sleep is history, we often label our 2am awakenings, “insomnia,” and view them as an abnormal condition to struggle against. Ekirch interprets it much differently:

“Nocturnal awakenings aren’t abnormal at all; they are the natural rhythm that your body gravitates toward….it is the compressed, continuous eight-hour sleep routine to which everyone aspires today that is unprecedented in human history. The dominant pattern of sleep, arguably since time immemorial, was biphasic.”

In other words, waking up in the middle of the night is not our fault! We once accepted it as natural, but electric light made it a problem by shortening the time we spend in bed.

Overcome Edison and Reconquer Sleep

too much sleepWe could certainly try to recreate natural biphasic sleep by going to bed a couple of hours earlier. That strategy would allow us time for the between-segments wakefulness. It might work, though most of us are simply not willing to sacrifice evening activities in order to hit the sack at 8 o’clock. But understanding why we awake in the middle of the night is a step toward better sleep. As interpreted by a lesson one of Ekirch’s grateful readers shares with us:

“I thought I was an insomniac. Struck night after night with sudden wakefulness at 2am or 2:30am in the morning. I would fight it, I would try to go back to sleep, I’d drink tea. I would do all the things that everyone tells you to do for insomnia, but none of it really worked. Years later, I’ve learned to embrace my wakefulness instead of fighting it.”

Accept Your Natural Biphasic Sleep Pattern

biphasic sleep acceptanceIronically, acceptance of night wakefulness was her first step to getting back to sleep more easily. Do give it a try. And do erase the word, “insomnia,” from your vocabulary. “Wakefulness” has a much gentler and more soothing ring. Turn on the light, have a snack and relax in the knowledge that, awake or in the deepest sleep, you are far safer and more comfortable than your ancestors.

There is probably no Viking raiding party creeping up on your undefended village, your house has locks and smoke alarms, and you can always dial 911 if you do spot real helmeted marauders. Finally, your mattress is (or should be) infinitely better than anything your ancestors slept on – nothing alive inside it, and no straws poking through the ticking.

In short, the hours you do sleep are likely deeper and more refreshing than the sleep of your great-great-greats – or even the sleep of their kings and queens. Had Columbus returned from America with an adjustable foam bed, instead of tobacco, Queen Isabella would probably have dumped King Ferdinand and replaced him with Christopher.

Biphasic or Not – You Need a Mattress

ecosa mattress reviewWe know that almost all modern mattresses are superior to those of the past, but everyone has a different idea about what is most comfortable – maybe Isabella would have preferred coil construction. There are more options than anyone could try out in a lifetime, but there is a shortcut to finding the right one for you.

Wither your goal is to try getting a seven to eight hour night of sleep. Or a more natural biphasic style, Our Sleep Guide will help you sort through hundreds of choices of mattresses. Narrowing the field by selecting characteristics you already know you prefer; harder or softer feel, foam or coil, inexpensive or “the sky’s the limit.” And once you’ve made your choice, you’re not stuck with it. Most online mattresses come with return privileges.

So jump over to some of our favorite mattresses HERE! Or peruse our list of mattress options HERE. You can’t go wrong with so many great options readily available. So, good hunting! – and quit worrying about waking up occasionally – it’s part of sleeping!

Thanks Uncle CT, our contributing writer, for another great piece! Learn plenty with all of his informative and fun to read pieces.