The Science of Sleep

More often than not, we tend to put our sleep aside, to make work for our studies, our work, some fun times, or simply to unwind if we have not found the time during the day. Whatever the reason may be, it can and usually does take away from our well being. Our bodies and our brains are both synched and our biorhythm is such that it has it’s own clock an knows on it’s own when it’s the time for rest and relaxation. But what happens when we do not listen to that clock? What do we do to ourselves when we decide to stay up a bit more, watch that one more episode, play the game for just 5 more minutes? How does that influence us?

Jansen, E. (2020, March 2). [Man sleeping happily]. University of Michigan – School of Public Health. https://sph.umich.edu/pursuit/2020posts/why-sleep-is-so-important-to-your-health.html

As an important part of our daily routine – we spend about one-third of our time sleeping. Quality sleep is as essential to survival as food and water.  Without sleep we can’t form or maintain the pathways in our brain that let us learn and create new memories, and it’s harder to concentrate and respond quickly.

Everyone needs sleep, but even so, its biological purpose remains a mystery.  Sleep affects almost every type of tissue and system in the body – from the brain, heart, and lungs to metabolism, immune function, mood, and disease resistance.

By definition, sleep is the natural, easily reversible periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one’s surroundings, and is accompanied by a typical body posture (such as lying down with the eyes closed), the occurrence of dreaming, and changes in brain activity and physiological functioning, is made up of cycles of non-REM sleep and REM sleep, and is usually considered essential to the restoration and recovery of vital bodily and mental functions.

Traditionally, sleep is divided into 4 categories: 

• Awake
• Light
• Deep
• REM Sleep

Heggarty, W. (2020, September 22). [Man in deep slumber]. Flourish Australia. https://www.flourishaustralia.org.au/panorama/importance-sleep

Each one plays an essential role in maintaining your mental and physical health.

Awake time is defined as the time spend in bed before and after falling asleep and it includes brief awakenings during sleep.

Light sleep guides us into deeper stages. Muscles relax and may jerk, respiration slows, heart rate decreases and the body temperature drops. It is the time when sleep begins or the transition between the cycles. This is Stage 1 – when we drift from being awake to being asleep. The light, NREM sleep that doesn’t last very long. You may start to relax and dream, but may also twitch as you transition into stage 2, which is still a light sleep, but we are drifting into a steadier sleep.

Deep sleep focuses on restoring your body. Blood pressure drops, and the body promotes muscle growth and repair – blood flow increases to muscles, growth hormone is released, tissue is growing and the cells repair. Our brain flushes waste and shows long, slow brain waves. Waking up in this stage is more difficult, and we are disoriented or groggy if awoken. This is when we enter stages 3 and 4 is the deepest sleep stages.

And finally, REM sleep re-energizes our minds. Our respiration and heart rate increases, as our temperature regulation is switched off. Vivid dreams are an occurrence, and our body becomes immobile to stop us from acting the dreams out. The REM faze benefits our memory, learning and problem solving. The first REM cycle of the night begins about 90 minutes after we fall asleep and recurs every 90 minutes. Our eyes move around quickly behind our eyelids and our brainwaves look similar to those of someone who is awake, which also results in our breathing, heart rate, and blood pressure rising to near-waking levels.

In healthy adults, about 13% to 23% of sleep is deep sleep. So if we sleep for 8 hours a night, that’s roughly 62 to 110 minutes.

However, as we get older, we require less deep sleep.

During deep sleep, a variety of functions take place in the mind and body:

• Memories are consolidated

• Learning and emotions process

• Physical recovery occurs

• Blood sugar levels and metabolism balance out

• The immune system is energized

• The brain detoxifies

[Dreaming and sleeping]. (n.d.). Kraks. https://kraks.co/quiz/how-much-do-you-know-about-sleep/

Without deep sleep, these functions cannot take place and the symptoms of sleep deprivation kick in. On the other hand, there doesn’t seem to be any such thing as too much deep sleep.

Some of the side effects of sleep deprivation include:

• Memory troubles
• Mood changes
• Weakened immunity
• Trouble concentrating
• Poor response time and increased risk of accidents
• High blood pressure
• Weight gain
• Risk for diabetes
• Low sex drive
• Risk of hear decease 
• Poor balance
• Early ageing

Resources:

Brain Basics: Understanding Sleep | National Institute of Neurological Disorders and Stroke. (n.d.). National Institute of Neurological Disorders and Stroke. Retrieved May 30, 2021, from https://www.ninds.nih.gov/Disorders/Patient-caregiver-Education/understanding-sleep

What Are The Stages Of Sleep? (n.d.). Oura Ring. Retrieved May 30, 2021, from https://ouraring.com/blog/sleep-stages/

What Happens to Your Body During Deep Sleep. (n.d.). WebMD. Retrieved May 30, 2021, from https://www.webmd.com/sleep-disorders/sleep-body-effects

How Much Deep, Light, and REM Sleep Do You Need? (n.d.). Health Line. Retrieved May 30, 2021, from https://www.healthline.com/health/how-much-deep-sleep-do-you-need#sleep-deprivation