Previous post: The Importance of Sleep
While we are all subject to the 24-hour circadian rhythm, we have different chronotypes, or patterns of sleeping and waking. The extremes of chronotypology include morningness (advanced sleep period), or so-called larks or early birds; and eveningness (delayed sleep period), or nightowls . While the causes, regulation and flexibility of chronotypes is still not fully understood, “normal variation in chronotype encompasses sleep–wake cycles that are from about two hours earlier to about two hours later than average” . In addition to light, heat can influence our chronotype, which is in turn influenced by climate, time of day, eating times and metabolism.
According to a study of young adults, the minimum body temperatures that precede waking occurred later in evening types (6:00 a.m.) than morning types (4:00 a.m.) . This could be due to different dinner times, metabolic rates, or late nights spent watching television, or working on a computer, which may change the melatonin production that signals when it is time to go to bed. In fact, the light from the screens of our electronic devices, “reset the biological clock in accordance with the phase response curve (PRC). Depending on the timing, light can advance or delay the circadian rhythm” . In order to maintain consistency in our sleep schedule, and to avoid sleep problems, we need to turn off our computers and televisions and have a winding down period before bed.
Based on the differences in chronotype, we have to conclude that the 8 (or 9) to 5 work schedule was designed for larks, or A-people, and is not ideal for nightowls, or B-people, who reach peak alertness and productivity later in the day. To redress the imposition of a work schedule that is hard for them to adapt to, Danish B-people have founded their own international NGO, B-Society. As their website states:
“Just think of the potential benefits if the working hours were optimal for the employees. This would not only increase productivity, but enhance the quality of life in the companies and in the communities.”
Another group of B-people that would benefit from a later schedule are young adults, many of whom are half-awake or sleep through their first classes of the day. Teenagers need more sleep than adults, typically between 8 ½ and 9 ¼ hours a night, so pushing the school start time forward from 7:00 a.m. to 8:30 a.m. (as advocated by the National Sleep Foundation) would give them the extra sleep they need to perform at their best, and avoid the many problems that sleep deprivation can cause including increased risk of accidents, irritability, lack of concentration, and poor impulse control.
Currently, the existing school start time seems to be geared more toward preparing students for the standardized early work schedule of modern society, than providing them with an optimal time to learn. This is the same schedule that causes adult B-people health problems, as a consequence of trying to fit into a schedule tailored for the A-person chronotype, which is only 10%-15% of the population . While "rise and shine" is an inspiring slogan to start the day, the ability to "shine" depends on your chronotype and when you have to get up.
Gas lights and electricity were important innovations of Second Industrial Revolution, which definitively changed people’s relationship to work. Industrialists could now operate their factories using shift workers at all hours, in order to maximize production and profit. Shops could stay open longer, and entertainment was available late into the night in the newly illuminated cities. With the transition from an agrarian to an industrial economy, there was also a change in people’s attitude toward time. Instead of rising early and going to bed early, as Benjamin Franklin advised, people could now rise early and stay up late to maximize their productive hours, consolidating Franklin’s adage of “time is money” into a way of life. While before people used to "pass" the time: in between harvests, or in the few hours of waking between their first and second slumbers, with electricity they now "spent" time, and time spent not earning money came to be considered wasting time.
Fast-forward to modernity and it is not uncommon to hear someone brag about how little sleep they get, the implication being that they are saving this time to work more, believing that they can beat the competition by sleeping less, but harming their own health and well-being in the process. “Although society often views sleep as a luxury that ambitious or active people cannot afford, research shows that getting enough sleep is a biological necessity, as important to good health as eating well or exercising” . The problem with not getting enough sleep is that it puts people at risk for drowsy driving, injury, and illness and can impair mental abilities, emotions, and performance . People who are sleep-deprived often depend on caffeine to get them through the day. According to drowsydriving.org:
"The National Highway Traffic Safety Administration conservatively estimates that 100,000 police-reported crashes are the direct result of driver fatigue each year. This results in an estimated 1,550 deaths, 71,000 injuries, and $12.5 billion in monetary losses. These figures may be the tip of the iceberg, since currently it is difficult to attribute crashes to sleepiness."
So how much sleep do we really need? Based on the National Sleep Foundation’s most recent study (produced by an eighteen member expert panel of leading scientists and researchers), the typical adult needs between 7 and 9 hours sleep, while 6 or 10 hours may be appropriate from some individuals: more or less than that is either too little or excessive. A recent Gallup poll, indicates that 40% of Americans get six hours or less of sleep at night. In 1942, this figure was 11%. While the advent of electricity changed our sleep patterns, the fast pace of modern life and the ubiquity of the internet has us sleeping less, which impacts our health and well-being. It has also made it harder for us to fall asleep.
According to the CDC, "about 70 million Americans suffer from chronic sleep problems." While some may suffer from medical conditions such as sleep apnea, many suffer from insomnia as a result of being anxious or worried about their work, family, and social lives, and stressed about the hectic schedules they must keep in order to making a living, stay moving on the consumer treadmill, and maintain their social status. In the process they have forgotten what an important, enjoyable and creative activity sleeping can be.
1. Wikipedia. "Chronotypes." Retrieved 2015-12-04.
2. Logie, Bruce. "Larks and Owls." As quoted in Wikipedia, "Chronotypes."
3. Baehr, E.K.; Revelle, W.; Eastman, C.I. (June 2000). "Individual differences in the phase and amplitude of the human circadian temperature rhythm: with an emphasis on morningness-eveningness". J Sleep Res 9 (2): 117–27.
4. Wikipedia. "Circadian Rhythm." Retrieved 2015-12-04.
5. Kring, Camilla. "Chronotypes. Are You an Early or a Late Chronotype." Research. B-Society. www.b-society.org. Retrieved on 2015-12-04.
6. National Sleep Foundation. "Backgrounder: Later School Start Times." www.sleepfoundation.org. Retrieved 2015-12-04.
7. National Sleep Foundation. "How Sleep Works: Myths and Facts About Sleep." www.sleepfoundation.org. Retrieved 2015-12-04.