Thursday, June 6, 2019

The concept of Segmented Sleep cycle...

New perspective on person-specific sleeping habits and cycles...

Maybe You Should Be Sleeping Twice a Day Like They Did in Olden Times
Ashley Hamer
June 8, 2018

If you're among the third of Americans who have some trouble staying asleep through the night, we have good news: maybe you don't have to. It's totally possible to plan a sleep schedule that keeps you rested even if you hit a three-hour insomnia patch every night. In fact, that's how pretty much everyone slept through most of history.

We've Had First Sleep, But What About Second Sleep?

Historian A. Roger Ekirch brought the trend of segmented sleep to light in 2001. His findings revealed that people used to divide their sleep into two separate periods, often referred to as "first sleep" and "second sleep." Between these periods, people would do chores, read, pray, or even go outside to visit friends.

Ekirch delved further into this phenomenon by studying modern non-Western cultures, including indigenous communities in Nigeria, Central America, and Brazil. He found that many of them also slept in segments. "During the period of nighttime wakefulness, Ekirch showed, different cultures elaborated rituals — of prayer, lovemaking, dream interpretation, or security checks — and while the rituals varied, the pattern itself was so pervasive as to suggest an evolutionary basis that somehow became disrupted in the modern West," Benjamin Reiss writes in New York Magazine.

What Changed?

There are a few elements Ekirch points to that may have caused this radical shift in our sleep schedules, but the most prominent is the electric light. Before artificial lighting, you had to turn in when the sun went down since it was too dark to see what you were doing. But once powerful light came on the scene, more and more activities were possible later and later into the night, so bedtime got later and later. Wake-up times didn't, so something had to give, leading to the shrinking and eventual disappearance of that waking time between first and second sleep.

Modern research supports his theory: experiments in 1993 by psychiatrist Thomas Wehr showed that when people were deprived of artificial lighting for long periods of time, they began to wake up for a period in the middle of the night. When his participants were exposed to a light cycle with an extended period of darkness — 14 hours, to be exact — they naturally began a pattern of sleeping for four hours, waking for one to three, then sleeping again for another four. It suggests that a pattern of segmented sleep is hard-wired into our brains.

A Siesta for the Rest of Us

Maybe two-phase sleep cycles are better for your brain. But with electric lighting and modern technology, how can you apply that information to your own sleeping patterns? It all depends on how flexible your schedule is. If you're a 9-to-5 worker, you'd likely have to go to sleep a few hours after you get home from work to really reap the benefits — but if you work nights, there's another option.

We've already told you about how harmful working the night shift can be to your health, and some researchers believe that segmented schedules might be a solution that satisfies both staffing and biological needs. Split-shift work schedules would divide the 24-hour period into smaller sections of alternately working and resting. Research has shown that getting roughly seven to eight hours of sleep scattered over the course of a 24-hour period is pretty much equivalent to getting eight hours all at once. In any case, if you find yourself jolting awake at 2 a.m. every morning, you may want to give segmented sleeping a try.

For more ways to get a more restful night's sleep, check out "The Sleep Solution: Why Your Sleep is Broken and How to Fix It" by W. Chris Winter, M.D., dubbed the "sleep whisperer" by Arianna Huffington. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.


Why Do We Sleep? from: The Good Stuff
  • There is no solid scientific consensus on why we sleep.
  • Black rhinos sleep for one to two hours laying down, and three to four hours standing up.
  • Dolphins engage in unihemispheric sleep, which means that one half of the brain is resting while the other half is alert.

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