A good night’s rest is eight hours, so here are eight facts to match...
Without artificial light the outdoors was a dangerous place after dark and candles at home were expensive. There wasn’t much to do but go to sleep. This meant people were naturally waking up after about four hours before going back to sleep for another four hours later - known as the first and second sleeps. A study in the early 90s confirmed this as a natural sleeping pattern.
Street lighting changed how people used the nighttime. At first individual buildings and shops were required to provide lanterns but by the early 1800s gas lamps were becoming what we now recognise as modern street lamps, starting in Pall Mall, London. They had to be lit by hand every day - and 1500 across London still are. With safer streets people could do business and socialise much later into the night, going to bed early became seen as lazy.
Hippocrates, the grandfather of medicine, believed that during sleep blood retreated from the skin further into the body - as evidenced by bodies being cooler when sleeping. Other physicians and philosophers had other theories - Aristotle believed sleep was caused by “vapours” from the gut.
Scientists have even used plants to try to understand natural cycles and the phrase “biological clock” was coined by a German scientist in 1935 after studying bean plants.
It’s said that Leonardo da Vinci only slept for 15 minutes at a time, every 4 hours, known as “polyphasic sleep” and sometimes advocated as a productivity technique today. Other famously light sleepers include Donald Trump with three or four hours, Thomas Jefferson at 4 hours a night and Thomas Edison, who sometimes didn’t sleep for days while working.
On the other hand, the naps are just as important. Charles Darwin slept 9 hours a night and then another hour every afternoon. Winston Churchill would conduct a lot of business while still in bed and staff in the underground bunker where he ran World War II had to keep quiet so as not to disturb his afternoon naps of up to two hours.
The first sleeping pill was invented in 1903. For centuries before people had struggled with insomnia and other common sleeping conditions such as snoring, sleep apnoea and narcolepsy.
Though dreams had been studied and theorised about all through history it was Sigmund Freud who really opened up the field in 1900 with “The Interpretation of Dreams”. Scientists and doctors are still interested in dreams and research continues.
And if you are having trouble getting off to sleep for your eight hours it might be the blue light from your phone - find out more in blue light explained.
Do you fancy getting by on four hours a night?
Know any interesting facts about sleep?
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