Why is Sleep So Important? You May Be Surprised

why is sleep so important

By Jody McCutcheon

We do it for beauty, we do it like babies; deeper is better, and all we ever want is five more minutes of it.

Ah, sleep–that peaceful, revitalizing altered state of consciousness. The less we get, the more we realize how much we miss it. But really, how precious is sleep? But why is sleep so important? Is it the optional luxury many of us treat it as, or are we paying a heftier price than mere droopy eyelids by skipping it?

Sleep habits have certainly changed in the last few decades. According to Oxford University professor Russell Foster, we’ve lost an average of one to two hours nightly in the last sixty years, and it’s hurting us. In fact, it may be killing us. The US Centre for Disease Control calls sleep deprivation a public health epidemic. Never mind America’s 80,000 yearly drowsy-driving-related motor vehicle accidents. Lack of sleep leads to serious short- and long-term health problems.

Why We’re Losing Sleep

The human circadian rhythm (or biological clock) was genetically encoded through millions of years of evolution. In all that time, things were relatively simple, with sunrise and sunset the prime indicators of waking and sleeping, respectively. But then came the Industrial Revolution, leaving in its wake extra-long work hours, artificial light and other social and technological intrusions on personal life; and in just a couple centuries, our circadian rhythm has been thrown for a loop. Consequently, we face a plethora of physical diseases and mood disturbances.

Modern life’s “time crunch” hasn’t helped our sleep hygiene, with its round-the-clock business hours, artificial light-dark schedules and pressures exerted by discrepancies between circadian rhythm and work/social schedules (aka “social jet lag”).

A major culprit is technology. Our use of devices tends to cut into sleep time. More importantly, though, the LED screens of these devices emit blue light, which basically mimics sunlight, thus tricking our bodies into thinking it’s daytime, no matter what time of day it is. Exposure to blue light prohibits our brains from releasing the sleep-inducing hormone melatonin, which is normally produced during nighttime darkness.

Melatonin suppression affects more than just cycles of shut-eye; it increases cancer risks, disrupts immune system functioning, and may also contribute to type 2 diabetes, heart disease, obesity and metabolic syndrome. But more about sleep deprivation consequences later.

Another common cause of sleep loss is social jet lag. The human preference for timing of sleep is called “chronotype,” an individual quality that’s regulated by circadian rhythm. Some people rise early, others late. Problems begin when chronotype conflicts with work and social schedules. Late risers have difficulty reconciling the two, and tend to sleep-restrict themselves during the week while sleeping longer on the weekend, thus further disrupting circadian rhythm.

A Globe and Mail article suggests that sleep deprivation begins at a young age, recounting an Australian study that concludes daily, hour-long naps in children aged four to seven actually reduce the quality and quantity of nighttime sleep, with effects lasting at least a year. And according to the US CDC, the poorer you are, the less sleep you get, partly because the poor tend to work more hours per week just to earn subsistence wages.

why is sleep so important


How Much Sleep Do You Need?

Multiple hypotheses have been proposed to explain the function of sleep. Perhaps the most comprehensive, updated explanation comes from a book by Richard L. Horner called The Universal Pastime: Sleep and Rest Explained. Horner expands the theory, first tabled by Aristotle, that sleep ultimately serves wakefulness–specifically that in sleep, brains process information garnered from previous waking experience, thus rewiring the brain to optimize more flexible behaviour in subsequent periods of wakefulness. This behaviour is favourably recognized by natural selection, thus increasing chances of survival, and even hastening evolution of the species.

England’s National Health Services suggests good sleep hygiene requires adults to get between six and eight hours of sleep nightly, while America’s National Sleep Foundation suggests between seven and nine hours. Yet most of us receive less than seven, while United Kingdom organization The Sleep Council suggests one in three people gets as little as four hours a night. Generally, there is a U-shaped association between sleep duration and health problems. Those who sleep longer than eight or nine hours a day, or fewer than six, tend to have associated medical conditions. With age, people normally tend to take daytime naps to increase their alertness, and correspondingly sleep less at night. Otherwise, we tend to get our sleep in one sustained block.

This wasn’t always the case. History suggests that our circadian rhythm evolved such that, in the absence of artificial light and industrial shift work, we engaged in something called polyphasic sleep, which is common in the animal kingdom. In this bimodal pattern, humans would slumber for about four hours starting shortly after dusk, wake for a couple hours–a time often used for sex or restful, meditative daydreaming–then do another roughly four-hour block of sleep. Together, the “first” and “second” sleeps, as they’ve been called, totaled about eight and a half hours.

Polyphasic sleep started to disappear from the human repertoire in the eighteenth and nineteenth centuries, i.e., after the Industrial Revolution, or relatively recently in human evolution. Yet only about two decades ago, scientist Thomas Wehr, in conjunction with the National Institute of Mental Health, performed sleep studies in which polyphasic sleep patterns quickly reappeared.

Wehr subjected participants to conditions mimicking ten hours of day and fourteen hours of night. After just a few days of adjustment, subjects found themselves sleeping in two distinct phases (“first” and “second” sleeps), each about three to four hours in length, broken by a one-to-three hour period of wakefulness. This experiment suggests that, evolutionarily at least, waking during night sleep is a normal part of human physiology.

What if many of our sleep disturbances are rooted not just in the proliferation of artificial light and modern life’s twenty-four-hour schedule, but also in the human body’s natural preference for–and subsequent divergence from–polyphasic sleep?


Health Consequences Of Sleep Deprivation

Sleep maintenance insomnia, for example, is a condition in which people awaken during the night and have difficulty returning to sleep. Such a disruption may hearken back to polyphasic sleep habits; but rather than embrace the wakeful period, people grow increasingly anxious about being unable to immediately fall back asleep, and that anxiety may ultimately prohibit them from doing so.

Or consider that the mid-night waking period of meditative rest and relaxation historically may have played a significant part in stress regulation; perhaps without it, or with the anxiety that being unable to return to sleep brings, we no longer manage stress as easily.

Oxford professor Foster says that thirty percent of medical problems confronted by doctors are related to sleep disturbances. The problem is, generalized medical training covers sleep hygiene only in broad strokes, if at all. As a result, many physicians may not recognize aberrant sleep or its corresponding consequences.

These consequences can be physical or mental, with short- or long-term impacts. For starters, sleep deprivation generally hinders concentration, memory, judgment and social skills, and not just in humans. Sleep-deprived honeybees and rodents, for example, also display such impairments. Problem-solving and quick-thinking cognitive abilities are also affected.

In the short term, sleep deprivation is associated with hair loss, weight gain, hormone imbalance, infertility, lowered immune function and premature aging. Longer term, it increases risks of cancer, heart disease, mental health issues, type 2 diabetes, obesity, infections and impaired productivity. A 2010 University of Warwick study suggests that sleeping less than six hours per night significantly increases the risk of premature death.

Lower-income shift workers–whose sleep patterns are often all over the place–are more susceptible to diabetes, obesity, cancer, stroke and heart attack. Research has also linked social jet lag with smoking, drinking and depression. And how about this possibility: if an inability to maintain concentration (i.e., attention) is a consequence of sub-optimal sleep, it’s not unreasonable to speculate that sleep disturbances in children may contribute to Attention Deficit Disorder. One study suggests only fifteen percent of North American children sleep more than eight and a half hours a night, when nine hours is optimal.

Taking alcohol or sedative drugs can help induce sleep in the very short term. Long-term, however, it’s a perilous strategy. Mixing drugs, even when individual doses themselves aren’t lethal, can be fatal (think Heath Ledger, Michael Jackson). Or people can become drug-dependent, making insomnia’s solution part of its cause. Another serious problem with sedatives is that they make the brain inactive. Yet sleep is an active brain state: while we sleep, our brain still works hard to perform its necessary functions. Drug-free sleep benefits brain and body function.

Finally, in the deep long-term, continual sleep deprivation hinders sleep’s capacity to shape and rewire the brain to optimize survival behaviour, thus leaving humans vulnerable to competitors. Disruption of this process leads to lethal problems in an evolutionary sense.

why is sleep so important
Jules Pascin: Sleeping Woman

Better Sleeping Solutions

Many drug-free ways exist to improve sleep and optimize its benefits:

  • The most basic strategies are ensuring proper diet, regular exercise and sleeping/waking hours, avoiding alcohol, caffeine and excess food before bed. Check out our sleep guide for more tips.
  • Quitting smoking can certainly help: a 2008 Johns Hopkins study found smokers were four times more likely than non-smokers to feel tired after a night of sleep.
  • A warm bath raises body temperature; when you emerge from the bath, your body temperature cools rapidly, making you sleepy.
  • Meditation and yoga relax the body and quiet the mind. America’s National Sleep Foundation endorses relaxation training and cognitive behavioural therapy as effective insomnia treatments.
  • Aromatherapy is also beneficial. Studies such as this one advocate the soporific effects of certain scents, especially lavender.
  • Some dietary supplements also work. Calcium and magnesium are sleep-boosters, especially when taken together. Wild lettuce alleviates restlessness and anxiety. Hops is often used as mild sedative. The amino acid L-theanine promotes calmness during the day and drowsiness at night.
  • Stay off electronics before bed. Harvard Medical School suggests avoiding blue light two to three hours before going to bed. If you must use your laptop or phone late into the evening, try wearing blue-blocker sunglasses. Seriously! Studies (e.g., here and here) show they effectively block blue light. In general, expose yourself to plenty of light during the day, particularly blue. This helps you maintain wakefulness and alertness and ultimately improves nighttime sleep quality.
  • Keep the bedroom dark. Since patterns of light and dark regulate circadian rhythm, also try to ensure sufficient exposure to darkness. This regulates sleep cues, including decreased body temperature, slowed metabolism and increased melatonin production. Use a sleeping mask if your blinds are inefficient.
  • Take melatonin supplements. As this is a hormonal supplement, it’s wise to consult with a doctor first, but these little pills can help with insomnia, jet lag and Seasonal Affective Disorder.
  • Make sure your partner isn’t waking you up!  You may not realise it, but you could be waking up several times in the night due to your partner taking the blankets from you, moving around or snoring.  Some couples find separate duvets or twin beds moved together are a good solution, while others may just have to sleep in separate beds or use an anti-snoring aid  or other proven solutions to get some decent shut eye.
  • Ensure your bedding is comfortable. A mattress that’s too hard or soft, a duvet that’s too heavy or too light, scratchy sheets, pillows that are too high or too low can all keep you from getting a good night’s kip. No need to buy a whole new mattress if yours is old: consider using a mattress topper to help freshen up your mattress and adjust its firmness level.
  • Try breathing and meditation techniques to calm you into a deep sleep. There are plenty of options on YouTube, like this:

Clearly, good sleep is necessary for good health, so much so that we believe medical schools need to wake up and add comprehensive sleep education to general medical training, which could better equip physicians with necessary skills to identify and treat sleep issues in patients. You can also improve your own sleep hygiene by using the above suggestions, but please consult a medical professional before starting any supplement regime.

If all else fails, try a week of camping. A pristine day-night cycle, such as that found in the wilderness, will properly reboot your circadian rhythm and you’ll sleep like a baby. Just remember to bring a good mattress.

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Main image: Eve Mattresses

Jody McCutcheon

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