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Sleeping 101: How Much Sleep Do We Actually Need

October 12, 2017


How often do you blame yourself for not getting eight hours of sleep every night? You know it’s detrimental to your health, at least that’s what countless doctors and physicians claim, but you simply do not have the luxury to pull an eight-hour snooze fest each night.

Or, you do manage to get a good eight-hour sleep every night yet you still wake up feeling exhausted. The explanation is simple: sleeping eight hours every night might not be the best option for you.

Everyone is different,” says Matt Bianchi, director of the sleep division at Massachusetts General Hospital. “Some people drink caffeine and get a rush while others don’t. One person might be fitted for polyphasic sleep [sleeping in short multiple blocks throughout the day], but someone else gets sleepy and crashes their car.”

People Used to Sleep in Two Shifts

The reality is that people only began sleeping in eight-hour blocks in the early 18th century, when the eight-hour day movement or 40-hour week movement took off. Up until then our sleeping patterns were completely different from what we’re used to now.

Research shows that until the age of electricity, people used to sleep in two shifts. They would wake up in the middle of the night for an hour or two, read, do some house chores or have sex, then return to sleep for another block of time, usually until the break of dawn.

“The dominant pattern of sleep, arguably since time immemorial, was biphasic,” says Roger Ekirch, a sleep historian at Virginia Tech University and author of At Day’s Close: Night in Times Past. “Humans slept in two four-hour blocks, which were separated by a period of wakefulness in the middle of the night lasting an hour or more. During this time, some might stay in bed, pray, think about their dreams or talk with their spouses. Others might get up and do tasks or even visit neighbors before going back to sleep.”

References to “first sleep” and “second sleep” can also be found in literature, pre-Industrial era archival documents and even historical legal depositions. Roger Ekrich came across the two-phase sleeping pattern in Chaucer’s “The Canterbury Tales“: “Ekirch somehow rediscovered a fact of life that was once as common as eating breakfast. Every night, people fell asleep not long after the sun went down and stayed that way until sometime after midnight. This was the first sleep that kept popping up in the old tales. Once a person woke up, he or she would stay that way for an hour or so before going back to sleep until morning – the so-called second sleep”.

Dickens’s Barnaby Rudge also references two periods of sleep being the norm in their era: “He knew this, even in the horror with which he started from his first sleep, and threw up the window to dispel it by the presence of some object, beyond the room, which had not been, as it were, the witness of his dream.”

This two-stage sleeping pattern may seem odd to you now, but it is in fact determined by our circadian clock. Our body reacts to artificial light in the same way it reacts to natural light – too much of it inhibits the release of melatonin, a sleep-regulating hormone made by your body’s pineal gland.

More evidence was uncovered by psychiatrist Thomas Wehr who conducted a laboratory experiment in the early 1990s to determine whether our normal sleeping pattern was monophasic or polyphasic. Wehr, who was then working at the National Institute of Mental Health in Bethesda, Md., exposed his subjects to short photoperiods in which they were left in the darkness for 14 hours each day, for a month.

As the fourth week approached, a distinct two-phase pattern emerged, suggesting that biphasic sleep is a natural process supported by our biological clocks. Once his subjects were completely deprived of artificial light, they began waking up in the middle of the night, lying awake in bed, contemplating their dreams or simply engaging in conversation with their partners. It was the same segmented sleep pattern referenced by Professor Ekirch in historical records and early works of literature.

If monophasic and biphasic sleep don’t appeal to you, don’t worry, there are plenty of options left for you to explore.

The most common polyphasic sleeping schedules

The Dymaxion Sleep Schedule: it consists of 30-minute “naps” every 6 hours; also known as “one of the most formidable sleep schedules on the market”. This sleeping schedule was coined by Buckminster Fuller and is said to be successful only for very short sleepers, a.k.a the people who carry the genetically mutated gene DEC2, a gene that allows them to fall into a deep state of REM sleep very quickly. While extremely difficult to follow, this particular pattern boasts increased convenience to the person’s social and work life.

The Uberman Schedule: one of the most attempted and most failed polyphasic sleeping schedules; it consists of six 30-minute naps per day, sometimes 20-minute naps. A 6 nap schedule (2h total sleep) will consist of a nap every 4 hours, having a 2-hour BRAC and a 4-hour rhythm, while an 8 nap schedule (2h40 min total sleep) will consist of a nap every 3 hours, having a 1.5-hour BRAC and a 3-hour rhythm.

The Everyman Schedule: the most successful reduced-sleep schedule to date; it consists of a core three-hour sleep during the night plus three 20-minute naps during the day. The original Everyman sleep schedule requires a core sleep period from 1 am to 4 am, a nap at 9 am, one at 2 pm, and another one at 9 pm. However the formula can be adapted to fit a working individual’s schedule as follows: a core sleep from about 11 pm to 2 am, then a nap at 7 am, one at 12 pm, and another nap at 6 pm.

Oversleeping is not the solution to your problems

While too little sleep might be a problem for the majority of the population, people often forget that too much sleep can also have a negative impact on their health. According to researchers, oversleeping has been linked to higher mortality rates, impaired brain functioning and mental health diseases.

Some studies have shown that memory impairment and decreased cognitive function are also linked to longer sleep, while other research suggests that people who tend to sleep more than eight hours per night have shown an increased risk of incident dementia.

What’s more, too little or too much sleep can also lead to chronic inflammation in the body, which is tied with an increased risk of diabetes, heart disease or Alzheimer’s.

The secret to healthier sleep

There are a myriad of health conditions that stem from unreasonable sleeping patterns. From glucose tolerance and weight gain, to heart diseases and infertility. Achieving the perfect sleep-to-wake ratio still remains one of humanity’s most intangible quests. So here are a few tips from Nancy H. Rothstein, The Sleep Ambassador and Director of CIRCADIAN Corporate Sleep Programs, that should help you avoid oversleeping so you can wake up refreshed and ready to conquer the world:

  • Select the optimal number of sleep hours that allow you to function at your best.
  • Then, determine your wake time, likely based on your work schedule or family demands.
  • Get up at the same time everyday, including weekends.
  • Avoid hitting the snooze button. Put your alarm clock across the room so when it rings, you have to get up.
  • Make a point of going to bed at the same time every night, within about half an hour range.
  • Commit to this pattern for at least two weeks, with a goal of four, then reevaluate your sleep and wake times.