FREE NEWSLETTER: Econintersect sends a nightly newsletter highlighting news events of the day, and providing a summary of new articles posted on the website. Econintersect will not sell or pass your email address to others per our privacy policy. You can cancel this subscription at any time by selecting the unsubscribing link in the footer of each email.

posted on 18 June 2016

Did We Used To Have Two Sleeps Rather Than One? Should We Again?

from The Conversation

-- this post authored by Melinda Jackson, RMIT University and Siobhan Banks, University of South Australia

Around a third of the population have trouble sleeping, including difficulties maintaining sleep throughout the night. While night time awakenings are distressing for most sufferers, there is some evidence from our recent past that suggests this period of wakefulness occurring between two separate sleep periods was the norm.

Throughout history there have been numerous accounts of segmented sleep, from medical texts, to court records and diaries, and even in African and South American tribes, with a common reference to "first" and "second" sleep. In Charles Dickens' Barnaby Rudge (1840), he writes

He knew this, even in the horror with which he started from his first sleep, and threw up the window to dispel it by the presence of some object, beyond the room, which had not been, as it were, the witness of his dream.

Anthropologists have found evidence that during preindustrial Europe, bi-modal sleeping was considered the norm. Sleep onset was determined not by a set bedtime, but by whether there were things to do. Historian A. Roger Ekirch's book At day's close: night in times past describes how households at this time retired a couple of hours after dusk, woke a few hours later for one to two hours, and then had a second sleep until dawn.

During this waking period, people would relax, ponder their dreams or have sex. Some would engage in activities like sewing, chopping wood or reading, relying on the light of the moon or oil lamps.

Ekirch found references to the first and second sleep started to disappear during the late 17th century. This is thought to have started in the upper classes in Northern Europe and filtered down to the rest of Western society over the next 200 years.

Interestingly, the appearance of sleep maintenance insomnia in the literature in the late 19th century coincides with the period where accounts of split sleep start to disappear. Thus, modern society may place unnecessary pressure on individuals that they must obtain a night of continuous consolidated sleep every night, adding to the anxiety about sleep and perpetuating the problem.

Biological basis

Less dramatic forms of bi-phasic sleep are evident in today's society, for example in cultures that take an afternoon siesta. Our body clock lends itself to such a schedule, having a reduction in alertness in the early afternoon (the so-called "post-lunch dip").

In the early 1990s, psychiatrist Thomas Wehr conducted a laboratory experiment in which he exposed a group of people to a short photoperiod - that is, they were left in darkness for 14 hours every day instead of the typical eight hours - for a month.

It may be that our bodies prefer sleeping in two phases. simpleinsomnia/Flickr, CC BY

It took some time for their sleep to regulate but by the fourth week a distinct two-phase sleep pattern emerged. They slept first for four hours, then woke for one to three hours before falling into a second four-hour sleep. This finding suggests bi-phasic sleep is a natural process with a biological basis.

Pros and cons

Today's society often doesn't allow for this type of flexibility, thus we have to conform to today's sleep/wake schedules. It is generally thought a continuous seven to nine-hour unbroken sleep is probably best for feeling refreshed. Such a schedule may not suit our circadian rhythms however, as we desynchronise with the external 24-hour light/dark cycle.

To successfully maintain a split sleep schedule, you have to get the timing right - that is commencing sleep when there is a strong drive for sleep and during a low circadian point in order to fall asleep quickly and maintain sleep.

Some of the key advantages of a split sleep schedule include the flexibility it allows with work and family time (where this flexibility is afforded). Some individuals in modern society have adopted this type of schedule as it provides two periods of increased activity, creativity and alertness across the day, rather than having a long wake period where sleepiness builds up across the day and productivity wanes.

In support of this, there is growing evidence suggesting naps can have important benefits for memory and learning, increasing our alertness and improving mood states. Some believe sleep disorders, like sleep maintenance insomnia, are rooted in the body's natural preference for split sleep. Therefore, split sleep schedules may be a more natural rhythm for some people.

Implications for shift work

Split sleep schedules have recently begun to emerge as a potential alternative to continuous night shift work. Working at night has the combined problems of prolonged wakefulness (often working eight to 12 hour shifts) and circadian misalignment (working at a time of night when you would normally be asleep). Shift workers frequently complain of fatigue and reduced productivity at work and they are at increased risk for chronic disease such as obesity, type 2 diabetes and heart disease.

Some industries have employed schedules with shorter, but more frequent sleep opportunities on the premise that the drive for sleep will be less with reduced time. For example, six hours on/six hours off, four hours on/eight hours off, and eight hours on/eight hours off, limit time on shift and reduce extended periods of wakefulness. Split sleep/work schedules divide the day into multiple work/rest cycles so employees work multiple short shifts, broken up with short off-duty periods every 24 hours.

Split-shift schedules that maintain adequate sleep time per 24 hours may be beneficial for sleep, performance and safety. A number of recent studies have found split sleep provides comparable benefits for performance to one big sleep, if the total sleep time per 24 hours was maintained (at around seven to eight hours total sleep time per 24 hours).

However, as might be expected, performance and safety can still be impaired if wake up and start work times are in the early hours of the morning. And we don't know if these schedules afford any benefits for health and reduce the risk for chronic disease.

While the challenges of night shift work cannot be eliminated, the advantage of some split shift schedules is that all workers get at least some opportunity to sleep at night and do not have to sustain alertness for longer than six to eight hours.

Although we aspire to have consolidated sleep, this may not suit everyone's body clock or work schedule. It might in fact be a throwback to a bi-model sleep pattern from our pre-industrial ancestors and perhaps work well in a modern industrial setting.

The ConversationMelinda Jackson, Senior Research Fellow in the School of Health and Biomedical Sciences, RMIT University and Siobhan Banks, Senior Research Fellow, Centre for Sleep Research, University of South Australia

This article was originally published on The Conversation. Read the original article.

>>>>> Scroll down to view and make comments <<<<<<

Click here for Historical News Post Listing

Make a Comment

Econintersect wants your comments, data and opinion on the articles posted.  As the internet is a "war zone" of trolls, hackers and spammers - Econintersect must balance its defences against ease of commenting.  We have joined with Livefyre to manage our comment streams.

To comment, using Livefyre just click the "Sign In" button at the top-left corner of the comment box below. You can create a commenting account using your favorite social network such as Twitter, Facebook, Google+, LinkedIn or Open ID - or open a Livefyre account using your email address.

You can also comment using Facebook directly using he comment block below.

Econintersect Contributors


Print this page or create a PDF file of this page
Print Friendly and PDF

The growing use of ad blocking software is creating a shortfall in covering our fixed expenses. Please consider a donation to Econintersect to allow continuing output of quality and balanced financial and economic news and analysis.

Take a look at what is going on inside of
Main Home
Analysis Blog
Comments on Feyerabend’s ‘Against Method’, Part II
Comments on Feyerabend’s ‘Against Method’, Part III
News Blog
Mom Breaks Down In Tears When Son With Autism Meets Service Dog
Rail Week Ending 15 October 2016 Paints A Negative Economic View
What Is The New Normal For U.S. Growth?
Affordable Care Act And Its Effect On Part-Time Employment
The Speed Of Filling Jobs Is Declining
First Working Eggs Made From Stem Cells Points To Fertility Breakthrough
Infographic Of The Day: Mega Machines
Online Platforms Double Down On TV Programming
A History Of Mars Missions
How Tesla Out Innovates Traditional Carmakers
Schiaparelli's Descent To Mars In Real Time
September 2016 Existing Home Sales Still Not Excellent
September 2016 Leading Economic Index Improves Indicating Moderate Growth Ahead.
Investing Blog
Options Early Assignment - Should You Worry?
The 401k Plan Manager 17 October 2016
Opinion Blog
Prop. 51 Versus A State-Owned Bank: How California Can Save $10 Billion On A $9 Billion Loan
Obama's Middle East Policy Has Been A Complete Failure - Or Has It?
Precious Metals Blog
How Will The Election Outcome Impact Precious Metals?
Live Markets
21Oct2016 Market Close: Major US Indexes Close Flat On Low Volume, Crude Prices Resume Climb, US Dollar Stabilizes In Mid 98 Handle, Yes, Most Investors Are Worried Which Way This Market Will Go
Amazon Books & More

.... and keep up with economic news using our dynamic economic newspapers with the largest international coverage on the internet
Asia / Pacific
Middle East / Africa
USA Government

Crowdfunding ....



Analysis Blog
News Blog
Investing Blog
Opinion Blog
Precious Metals Blog
Markets Blog
Video of the Day


Asia / Pacific
Middle East / Africa
USA Government

RSS Feeds / Social Media

Combined Econintersect Feed

Free Newsletter

Marketplace - Books & More

Economic Forecast

Content Contribution



  Top Economics Site Contributor TalkMarkets Contributor Finance Blogs Free PageRank Checker Active Search Results Google+

This Web Page by Steven Hansen ---- Copyright 2010 - 2016 Econintersect LLC - all rights reserved