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What Is Sleep and Why Is It Important?

What Is Sleep and Why Is It Important?

Man asleep at his computer

What does sleep actually look like?

Sleep isn’t a static state, we actually go through several sleep cycles with varying levels of brain activity (stages) throughout the night. The stages are divided into two categories: Rapid Eye Movement (REM) and non-Rapid Eye Movement (NREM). NREM is further divided into 3 stages. How long we stay in each stage and if we are able to cycle through our stages undisturbed throughout the night will determine how good our sleep is. The better our sleep, the healthier we are.

Graph of brain waves during sleep
Image courtesy of Lumen

Stage 1: 1-5 minutes

  • Dozing off, sleep twitches phase
  • Body and brain activities start to slow
  • Light changes in brain activity

Stage 3: 20-40 minutes

  • Deep sleep
  • Muscle tone, pulse, and breathing decrease as the body relaxes even further
  • Brain shows pattern of delta waves
  • This is where recovery and growth happen. Positive links to improved immune system response as well as creativity and memory. 
  • Most deep sleep occurs in the first half of the night and gets shorter as the night progresses as it flips with REM sleep.
  • We spend about 13-23% of our sleep cycle in this deep sleep stage

Stage 2: 10-60 minutes

  • Body enters a more subdued state
  • Drop in temp, muscles relax, slower breathing and HR
  • Brain activity slows but there are short bursts of activity
  • Collectively, we spend about half our night here (gets longer each cycle)

REM: 10-60 minutes

  • Brain activity really picks up, nearing awake state BUT our body is paralyzed with the exception of our eyes and breathing muscles
  • Hence the name Rapid Eye Movement
  • This stage essential for memory, learning, and creativity
  • Dreams occur in this stage
  • REM makes up about 25% of sleep in adults
Graph of the different stages of sleep
Image courtesy of Lumen

What can alter or disturb our sleep cycles?

In order to feel rested from our sleep we want to spend as little time in stage 1, where we are trying to fall asleep, and want to maintain the continuous cycle of sleep by staying asleep throughout the night. There are many different factors that can limit our ability to do this. 

There are lifestyle factors such as alcohol and caffeine consumption, drug use, and work/school schedules that can interfere with our sleep. Psychosocial factors such as stress and anxiety, being a parent to young children or a caregiver for a relative who is ill can further alter sleep and many other factors can keep us awake at night.

Annoyed woman with pillow over her earsThere are also environmental factors such as excessive lighting or noise that can make it difficult to fall asleep, or that can wake you up in the middle of the night. On the flip side, not getting enough sunlight during the day can also alter your circadian rhythm, your biological clock that tells you when you should be sleeping and when you should be awake, which may cause problems with sleep. This is linked to seasonal affective disorder which most often occurs in the winter months due to reduced daylight hours, especially if you live closer towards the Poles.

Furthermore, there are clinical sleep disorders. Susan L. Worley (2018) wrote an article where she states that approximately 70 million Americans had at least one sleep disorder and experts believed that an additional 80% of sleep disorders go undiagnosed. The American Academy of Sleep Medicine has classified sleep disorders into several categories:

  • Insomnia: Difficulty getting to sleep or staying asleep, with associated daytime consequences. This can be chronic.
  • Sleep-related breathing disorders: Sleep apnea and shallow breathing.
  • Central disorders of hypersomnolence: Excessive daytime sleepiness, such as narcolepsy or idiopathic hypersomnia. 
  • Circadian rhythm sleep-wake disorders: Sleep abnormalities due to misalignment between the biological clock and sleep times, such as shift work disorder or jet lag.
  • Parasomnias: Abnormal behaviours or events arising from sleep, such as sleep walking, sleep terrors, and REM sleep behaviour disorder. 
  • Sleep-related movement disorders: Abnormal, recurring movements in sleep, such as restless leg syndrome or leg cramps.
  • Other: Not classified elsewhere, such as environmental sleep disorders.
Tired woman looking at her alarm clock

What are the effects of a lack of sleep? 

I’m sure we have all muttered the phrase “look who woke up on the wrong side of the bed this morning” at one point or another in our lifetime. We typically use this idiom to describe someone who is grouchy or grumpy in the morning and throughout the day. I think it practically goes without saying that it is far more likely that the grouchy individual did not get a restful sleep as opposed to having anything to do with which side they got up on.  

Research has shown that individuals who are sleep deficient have a different stress response in comparison to those who get an adequate night’s rest. They have found that sleep deprived individuals respond to low stress situations the same way that rested people respond to high stress scenarios.

I am sure you have encountered an individual (or maybe even yourself) who snapped when someone touched their favourite pen or moved something on their desk. When we are sleep deprived our brain struggles to cope with stress and we may not respond to a minor offence how we normally would.

Does sleepiness contribute to increased rates of accidents and injury at work?

Man sleeping at work on his tailgateYes it does. Many studies, and I mean hundreds of studies, have looked at the effects that sleep deprivation has on health and safety in the workplace. Lack of sleep affects our brain function including reduced cognition, limited decision making ability, and decreased reaction time.  

One of the most studied areas of concern is motor vehicle accidents. One particular study found that those who only get 6 hours of sleep are at a 33% greater risk of having a motor vehicle accident than those who get 7 or 8 hours of sleep. Another article has even linked the nuclear disaster at Three Mile Island as well as the Space Shuttle Challenger accident to human error, either as a direct or indirect result of sleep deprivation.

In a review conducted by Uheli et al. (2014) that looked at the effects of sleep problems on workplace injuries, found that workers who reported having sleep disturbances were 1.62 times more likely to be injured at work compared to those without sleep issues. It was reported that 13% of workplace injuries could be attributed to sleep problems.

Woman asleep at her deskThe same article also discovered that those who used a sleep medication to help with their sleep disorder increased their risk for injury further. The authors attributed this to either the lingering effects of the narcotic aspects of the medication, or the assumption that those who needed the medication had more severe sleep disorders which would affect them more significantly.

Ensuring that employee work schedules allow for adequate rest in between shifts is one way to prevent workplace accidents and injuries, especially in high risk environments such as driving and industrial settings with heavy machinery as well as high pressure occupations such as control room operators.

How long should you sleep for?

The American Academy of Sleep Medicine and Sleep Research Society have determined that the ideal length of time for sleep is 7 hours or more for adults. When you start dipping below 7 hours you start to see negative effects. Sleeping more than 9 hours may be appropriate for teenagers or those trying to catch up on sleep, however it is undetermined if this poses a health risk for normal adults when done on a regular basis.

Woman waking up well rested

How can you improve your sleep?

If you are aiming for your 7 hours of sleep but are maybe having trouble falling, and staying asleep there are a few changes you can make to help.

Environmental Factors

  • Lighting
    • Increase the amount of daylight you get, this can help restore your natural circadian rhythm.
    • Decrease blue light exposure before bed, this means putting your electronic devices down!
    • Moderate light coming in from external sources like windows, digital clocks, and TV’s during the night.
    • Try a wake-up light, which simulates the sunrise for a more gentle and natural way to wake-up.
  • Noise
    • Wear earplugs or use white noise to reduce the distractions of noisy neighbours or traffic on the street.
  • Temperature
    • Try to keep your bedroom at room temp (20°C/68°F) or a tiny bit cooler (~18°C/64°F). This will make your under-the-covers temperature a comfortable 27°C/81°F.
    • Use a blanket that is appropriate for the season. Light sweat wicking material in the summer, and heavy heat trapping material for the winter.

Lifestyle Changes

  • Diet
    • Limit caffeine intake in the afternoon, caffeine can stay in our system for 6-8 hours.
    • Short term use of sleep aids, such as melatonin, can help reduce the effects of jet-lag.
    • Supplements like lavender, magnesium, and chamomile promote relaxation, which may help you fall asleep.
  • Exercise
    • Exercising during the day reduces stress and anxiety, which are contributors to sleep disruptions.
    • A recent study published in 2019 found that light exercise performed about 90 minutes before bed can actually help you fall asleep.
  • Daily Routine
    • Having a consistent waking and bedtime can help regulate your circadian rhythm making it easier to sleep.
    • If you did have a difficult night of sleep, having a short nap of about 10-20 minutes in the afternoon can help restore some of your cognitive function.

Stay Tuned For More!

You may have noticed something missing in our sleep articles so far, that would be sleep ergonomics of course! The final article in our Sleep Series will provide insight into the best positions for sleeping to prevent pain and discomfort as well as address what mattress and pillow types are the best to ensure you stay in a neutral posture as you sleep.

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