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Sleep

October 9, 2013

Not everyone is a scientist, but everyone sleeps, so even non-scientists will suffer through a little science for insights into this important and interesting topic. At the least, reading this article might cause them to nod off from boredom. According to an article in MarketWatch, 58.5 million prescriptions for sleeping pills were issued in 2012.[1] IMS Health, a Parsippany, New Jersey, marketing analytics company, estimates the present annual cost of sleeping aids in the United States alone to be $32.4 billion.[2]

Since humans can decide within limits how much sleep they get and the times that they sleep, sleep is somewhat of a behavioral trait. For that reason, it's interesting to study its history as well as its present practice. One of the more interesting things about sleep is that people prior to the Industrial Revolution didn't sleep as we do. Instead of our extended, typically eight hour, sleep period, our ancestors would divide the night into two sleeping periods.

Endormies by Rupert Bunny (1904)"Endormies" (Asleep, 1904) by Rupert Bunny (1864-1947).

Bunny divided his time between Paris and his native Australia.

(Via Wikimedia Commons.)

In medieval England, these segmented sleep periods were called "first sleep," or "dead sleep," followed by "second sleep," or "morning sleep." There was a period of activity between these which included such things as conversation and lovemaking. This was discovered in 2001 by A. Roger Ekirch, an historian at Virginia Polytechnic Institute and State University (Virginia Tech).[3]

Ekrich found more than 500 references to segmented sleep in such source materials as medical books, diaries, literature and court records. Such a sleep practice is also found among modern Nigerian tribes. The first sleep began about two hours after dusk, with a waking period of 1-2 hours before a second sleep. Such sleep habits seem to extend even farther back in time, since there appears to be a reference to first sleep in Homer's Odyssey.[3] Some sleep experts think that such a sleep pattern is better than our present pattern.

Everything important has a foundation, so we shouldn't be surprised that there's a National Sleep Foundation. The National Sleep Foundation has just published a study, called the 2013 International Bedroom Poll, of the sleep habits of individuals between the ages of 25 and 55 for six countries. These are the United States, Canada, Mexico, the United Kingdom, Germany and Japan. For this study, 1,501 telephone interviews, about 250 per country, were conducted among a random sample of people. For such a sample size, we can expect the margin of error to be within about 6 percent.[4]

Japanese and Americans appear to be the most overworked citizens, since they report sleeping about 30-40 fewer minutes on workdays than the other countries. About half of the Japanese and American interviewed reported that they had taken at least one nap in the prior two weeks. Non-working weekends were an oasis of sleep for all countries, with people sleeping an extra 45 minutes.[4]

A large proportion (23-27%) of people in the United States, Canada and the United Kingdom report that they never sleep well on work nights.[4] Bedroom environment is important to good sleep, and a fresh, pleasant scent is especially important. Says National Sleep Foundation CEO, David Cloud,
"Studies have shown that scent plays a powerful role in relaxation and memory-building... Having a pleasant scent and a relaxing bedroom routine can contribute to a good night's sleep. No matter what your nationality, you will spend about a third of your life in bed. Fresh air and a pleasant scent are great ways to improve your sleep experience."[4]

Some other interesting findings from the sleep study are that a third of people in the United Kingdom sleep naked, and 62% of Mexicans and 47% of Americans meditate or pray in the hour before sleep. More than two-thirds (66%-80%) of people in surveyed countries watch television in the hour before bed.[4]

Sleeping PuttoA Sleeping Putto, as depicted in an 1882 painting by Léon Bazille Perrault (1832-1908).

The putti are fanciful Cupid-like creatures who often represent peace and leisure.

(Via Wikimedia Commons.)

More sleep might aid not only your health, but your economic state as well. John Pollock, associate professor of biological sciences at Duquesne University, and creator of the children's science television series, Scientastic!, is quoted in the Pittsburgh Post-Gazette as saying,
"Kids who tend to get A's in school tend to get 15 minutes to a half-hour more sleep than kids who get B's... And kids who gets B's tend to get 15 minutes to a half-hour more sleep than kids who get C's."[5]
United States Secretary of Education, Arne Duncan, said in a September 4, 2013, radio interview on NPR, "I think there's lots of research and again sort of commonsense that a lot of teens... struggle to get up at 6:00 in the morning to get on the bus..."[6] There's also a recent study, published in the Proceedings of the National Academy of Sciences, demonstrating that children recalled 10% more spatial locations after a nap than if they had been kept awake for the napping period.[7]

References:

  1. Jonnelle Marte, "10 things the sleep-aid industry won't tell you," Market Watch, May 23, 2013.
  2. Maureen Mackey, "Sleepless in America: A $32.4 Billion Business," The Fiscal Times, July 23, 2012.
  3. Stephanie Hegarty, "The myth of the eight-hour sleep," BBC World Service, February 22, 2012.
  4. National Sleep Foundation 2013 International Bedroom Poll First to Explore Sleep Differences among Six Countries, September 3, 2013
  5. Cristy Gelling, "'Scientastic' promotes the link between learning and rest," Pittsburgh Post-Gazette, September 23, 2013.
  6. Susan Page, "A Back-To-School Conversation About Education," NPR, September 4, 2013.
  7. Laura Kurdziel, Kasey Duclos and Rebecca M. C. Spencer, "Sleep spindles in midday naps enhance learning in preschool children," Proc. Natl. Acad. Sci., September 23, 2013, doi:10.1073/pnas.1306418110 (PDF file).