Why Sleep Is Important: More Than You Think!

why is sleep so important

Feeling guilty about having a lie-in? You shouldn’t – sleep is important? Here’s why

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, revitalising altered state of consciousness. The less we get, the more we realise how much we miss it. But really, how precious is sleep? But why is it 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?

Why Do We Need To Sleep?

why do we need to sleep?

It would be so much easier if we could do without it. But we, and nearly all creatures on the planet, need to sleep. The thing is: we’re not sure why!

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. His The Universal Pastime: Sleep and Rest Explained, expands the theory, first tabled by Aristotle, that sleep ultimately serves wakefulness.

Specifically, in sleep, our brains process information garnered from previous waking experience. Consequently, our brains can optimize more flexible behaviour in subsequent periods of wakefulness. This behaviour is favourably recognized by natural selection, thus increasing chances of survival.

Of course, this is still just one theory, though. But no matter what the reasons may be for our slumber, one fact remains: we need to!

That said, 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, sleep is so important, a lack of it may be killing us!

The US Centre for Disease Control calls sleep deprivation a public health epidemic. A lack of sleep leads to serious short- and long-term health problems.

How Modernity Messes Us Up

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.

But then came the Industrial Revolution. It basically ignored the fact that sleep is so important in our lives. It left us with extra-long work hours, artificial light and other social and technological intrusions on our personal lives. After just a couple decades, our ancient circadian rhythm has been thrown for a loop. As a result, we face a plethora of physical diseases and mood disturbances.

Technology is a major culprit. Today, our use of devices – including computers, phones and digital TVs – tends to cut into sleep time. More importantly, the LED screens of these devices emit blue light, which basically mimics sunlight, thus tricking our bodies into thinking it’s daytime, all the time.

The Importance Of Melatonin

Exposure to blue light prohibits our brains from releasing the sleep-inducing hormone melatonin, which is normally produced during nighttime darkness.

Melatonin is a powerful and very necessary hormone. Its suppression is one of the main reasons sleep is so important. A lack of melatonin can have devastating effects, such as:

  • increased cancer risk
  • disrupting immune system functioning
  • contributing to type 2 diabetes, heart disease, obesity and metabolic syndrome
  • a decline in cognitive function
  • chronic insomnia

But more about sleep deprivation consequences later.

Social Jet Lag

Another common cause of sleep loss is something called ‘social jet lag’. This happens when life’s daily activities mess with your circadian rhythm.

The human preference for timing of sleep is called “chronotype.” This is an individual quality that’s regulated by circadian rhythm. Some people rise early, others later. Problems begin when chronotype conflicts with work and social schedules.

For example? Late risers have difficulty, say, getting to work at 9am. They tend to sleep-restrict themselves during the week and stay in bed longer at the weekends. Thus, they further disrupt their circadian rhythms.

But it’s not just adults who suffer from ‘social jet lag.’

A Globe and Mail article suggests that sleep deprivation begins at a young age. They cite an Australian study that concludes daily, hour-long naps in children aged four to seven actually reduce the quality and quantity of nighttime kip. Those effects can disrupt a kid’s snoozing patterns for at least up to a year.

How Much Sleep Do You Really Need?

By now, we know sleep is important. So, how much is enough?

England’s National Health Services suggests good sleep hygiene requires adults to get between six and eight hours nightly. America’s National Sleep Foundation suggests between seven and nine hours. Yet most of us receive less than seven!

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. Correspondingly, they sleep less at night. Otherwise, we tend to get our kip in one sustained block. Which isn’t really how we evolved.

Polyphasic Sleep

In fact, we humans used to slumber for about four hours starting shortly after dusk. Then we’d wake for a couple hours. That time was often used for sex or restful, meditative daydreaming. Then, we’d 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.

This polyphasic sleep started to disappear from the human repertoire in the eighteenth and nineteenth centuries. In other words, after the Industrial Revolution. This is very, very recently in terms of 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 snoozing in two distinct phases. Each was about three to four hours in length, broken by a one-to-three hour period of wakefulness. This experiment suggests that waking during night sleep is a normal part of human physiology.

The takeaway? The human body seems to prefer polyphasic sleep. But ‘social jet lag,’ modern technological devices and a chronic lack of melatonin production throw our bodies off.

And the results can be terrible.

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.

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 rest 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
  • premature aging
  • unstable moods and depression

Longer term, it increases risks of:

  • cancer
  • heart disease
  • serious mental health issues
  • type 2 diabetes
  • obesity
  • infections
  • impaired productivity

A 2010 University of Warwick study even suggests that sleeping less than six hours per night significantly increases the risk of premature death!

So no wonder 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 (ADD). 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 for them.

Drugs Don’t Help

Taking alcohol or sedative drugs can help induce sleep in the very short term. Long-term, however, it’s a dangerous strategy. Mixing drugs, even when individual doses themselves aren’t lethal, can be fatal (think Heath Ledger, for example). 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. Remember: sleep is an active brain state: while we rest, our brain still works hard to perform its necessary functions. A drug-free slumber benefits both brain and body functions.

Better Solutions

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

  • Consider your bedding. Mattress sizes and firmnesses vary. Ensure your bed is optimised for your comfort.
  • The most basic strategies are ensuring proper diet, regular exercise and sleeping/waking hours, avoiding alcohol, caffeine and excess food before bed.
  • A warm bath raises body temperature. When you emerge from the bath, your body temperature cools rapidly, making you more tired.
  • Meditation, breath work and yoga relax the body and quiet the mind
  • Studies show that using aromatherapy, such as lavender oil, is also beneficial
  • Some dietary supplements also work. Calcium and magnesium are slumber-boosters, especially when taken together. Valerian, chamomile, CBD oil, wild lettuce and hops are all also mild sedatives.
  • Stay off electronics before bed. Harvard Medical School suggests avoiding blue light two to three hours before slumber.
  • Keep the bedroom dark. This regulates sleep cues, including decreased body temperature, slowed metabolism and increased melatonin production.
  • Take melatonin supplements. As this is a hormonal supplement, it’s wise to consult with a doctor first.
  • 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.
  • Ensure your bedding is comfortable. A mattress that’s too hard or soft, a duvet that’s too heavy or too light, etc can all keep you from getting a good night’s kip.


Clearly, good rest 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. This 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.

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Main image: Eve Mattresses


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