Welcome back! In “Sleep Much (Part I)” we learned that many of our ancestors slept in a biphasic manner consisting of two sleep periods each evening with a quiet awake time in between, especially during the winter season. Some cultures that sleep in a biphasic fashion take a siesta or mid afternoon nap, especially in the hot summertime mid-afternoons. Young children, the elderly, and some by personal preference may take a short nap in the afternoon. It is interesting to note that there remains a billion people in the earth who still practice biphasic sleep.
Myth or Not?
Are humans fundamentally different from all the other animals because our sleep has been consolidated into one continuous nocturnal session? If one considers how other mammals such as dogs, cats, chimpanzees, horses, etc., sleep (which are actually poly-phasic in their sleeping patterns), man may not be so unique after all. In the annals of history well-known people such as Nikola Tesla, Leonardo DaVinci, Salvador Dali, Napoleon Bonaparte, and Winston Churchill have been recorded as having practiced polyphasic sleep.
The industrial revolution of the the late 18th and the late 19th centuries caused biphasic sleeping to lose popularity. Natural gas-powered street lamps increased in prevalence, especially in the cities. The first homes “wired” for artificial light were actually “plumbed” with gas pipes to gas-powered lanterns. Electricity was soon discovered, the modern light bulb was invented …and the artificial light pierced the darkness. » Read more