The Sleep Myth - 8 Hours a Night is "Normal"

It should come as a relief to people who don't sleep for 8 hours a night and think they have a sleep disorder, that contrary to what the sellers of expensive beds and prescription sleep medicine would like you to believe - you may actually be exhibiting "normal" sleep patterns that humans have been following for ages.

Some studies indicate that the idea that the norm is 8 hours of uninterrupted sleep during the night is a product of our industrial society rather than something humans are genetically predisposed to.

Prior to the 20th century - the lack of central heating/cooling, prevalence of illness, animals that needed to be tended to, and absence of artificial light – makes it reasonable to assume that people did not go to sleep and then wake up 8 hours later.

In prehistoric times uninterrupted sleep would have been even more difficult considering the dangers humans had to deal with – sleeping in a hut, or a cave, or on the ground - with some wild animals hanging around who might think a human would make a tasty treat, would not be conducive to sound sleep. Those who slept too soundly when the saber tooth cat, or warring tribe, showed up were removed from the gene pool.

Considering the goal of survival - protecting oneself and one's family from danger and caring for the young - there is nothing from an evolutionary standpoint that would make the ability to sleep for 8 hours without interruption a desirable human trait.

The obsession with the precise number of hours a person sleeps is a relatively recent development. Prior to the 19th century people didn't know if they got 8 hours of sleep a night because they didn't have clocks in their homes. It wasn't until the 19th century that "clock time" became important in developing an industrialized society.

Even though it may not be "normal" at all, there's a steady drumbeat from the makers of expensive beds and medicines trying to convince us that 8 hours of sleep needs to be everyone's ultimate goal. It's interesting to note that some studies show that prescription medications for sleep may not actually give us a better sleep, but rather interfere with our ability to remember – so we just don't recall tossing and turning after we wake up.

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NMAH | "On Time" Opens at Smithsonian's National Museum of American History

Acknowledging Preindustrial Patterns of Sleep May Revolutionize Approach to Sleep Dysfunction

NPR: A Fitful History of Sleep

Dreams Deferred - New York Times

At Day's Close: Night in Times Past