But, what's this all about? What first sleep?
These accounts describe a first sleep which began about two hours after dusk, followed by waking period of one or two hours, and then a second sleep.
During the waking period between sleeps, people were quite active. They often got up, went to the toilet or smoked tobacco and some even visited neighbors. Most people stayed in bed, read, wrote and often prayed. Countless prayer manuals from the late 15th Century offered special prayers for the hours in between sleeps.
In the wake of the Reformation and the counter-Reformation. Protestants and Catholics became accustomed to holding secret services at night, during periods of persecution.
Those who could afford to live by candlelight copied the trend. However, with the advent of street lighting, (the first in Paris, 1667) socializing at night began to filter down through the classes. By the end of the century, more than 50 of Europe's major towns and cities were lit at night.
By the 1920s the idea of a first and second sleep had receded entirely from our social consciousness.
Today, most people seem to have adapted quite well to the eight-hour sleep, but perhaps many sleeping problems have roots in the human body's natural preference for segmented sleep as well as the ubiquity of artificial light.
Waking period between sleeps, when people were forced into periods of rest and relaxation, could have played an important part in the human capacity to regulate stress naturally. So the next time you wake up in the middle of the night, think of your ancestors and relax. Lying awake could be good for you.
The ideal of eight hours' sleep each night is hard to achieve for many people. However, some experts now say it's too much, and may actually be unhealthy.
We all know that getting too little sleep is bad. You feel tired, you may be irritable, and it can contribute to obesity, high blood pressure, diabetes, and heart disease. But most people don't complain about too much sleep.
To put it more scientifically, there is a gradual increase in mortality risk for those who fall outside the six-to-eight-hour band.
A professor of cardiovascular medicine and epidemiology at the University of Warwick analyzed 16 studies. More than a million people were asked about their sleeping habits, and were followed up over time. Compared to the medium sleepers, 12% of the short sleepers and 30% of the long sleepers had died.
The magic number of hours asleep, according to the lead doctor at the Sleep Disorders Center at the University of Massachusetts Medical School may actually be seven. But if you enjoy sleeping, spend a lot of time in bed and feel good, rest assured. No extra time asleep or just lying down and relaxing will kill you.
I consider myself a good sleeper. I go to bed at 10pm and fall asleep within 10 minutes. I get up once to go to the bathroom, fall asleep fast and wake again at 7am. Instead of that time asleep adding to nine hours as I'd previously thought, the time I actually sleep might be closer to eight hours. No matter what it adds up to, I wake refreshed and look forward to the coming day.
My husband lies awake for the first part of the night worrying. He falls asleep in the early hours of the morning and has trouble waking before midday. As a child he would keep himself awake so his piano-playing father would take him to clubs in London. So much of his behavior stems from that, as well as his night work thereafter. But maybe, in part, his nonconformist sleeping comes from the way our ancestors slept.
How do you sleep?