What is Sleep?
According to Lexico Dictionary, Sleep is a condition of body and mind. Typically sleep recurs for several hours every night, in which the nervous system is relatively inactive, the eyes closed, the postural muscles relaxed, and consciousness practically suspended.
Why is sleep so important?
Many a time, I hear some persons say “why sleep when I can get enough sleep when I’m dead”, I bet we have also heard this statement. Over time, I have learnt that one cannot cheat nature; so when you do not get enough sleep, it affects you one way or another. Having little or enough sleep affects how we look, feel and perform our daily activity, and can have a significant impact on our overall quality of life.
Just like we need food and water to survive, we also need sleep; it is no wonder we spend about one-third of our lives sleeping. In essence, sleep is essential for good health.
Many Biological processes occur while we sleep, such as:
- Cell repairs by the body, release of hormones and proteins, restoration of energy.
- The disposes of toxic waste and stores new information.
- Nerve cells reorganize and communicate, thereby supporting healthy brain function.
The above processes are essential for overall health, and without them, our body would not function correctly. There are many other reasons why we need sleep, and we will outline the most prominent theories below
- Brain function :
sleep is essential for brain function as it allows your neurons, or nerve cells, to reorganize. When you sleep, the waste clearance system of your brain (brain glymphatic) removes waste which has built up throughout the day from the central nervous system. This allows your brain to work at optimum performance when you wake up.
Sleep affects many aspects of brain function, including decision-making, learning, concentration, memory, focus, creativity, problem-solving skills.
- Weight maintenance:
Sleep controls hunger hormones; ghrelin which increases appetite, and leptin, which increases satiety. Both hormones are regulated because while you sleep, less energy is used.
However, lack of sleep elevates ghrelin and suppresses leptin. This imbalance makes you hungrier, which may increase the risk of weight gain.
- Heart health:
Lack of sleep is associated with risk factors such as heart disease, including insulin resistance, weight gain, increased inflammation, high blood pressure, elevated cortisol levels, increased sympathetic nervous system activity.
When you sleep, your body produces certain antibodies, immune cells and small secreted proteins called cytokines. These antibodies help fight infection and inflammation; together, they prevent sickness by destroying harmful germs. For this reason, sleep is essential when the body is stressed or sick.
- Cellular restoration:
There is a theory called the restorative theory, says the body needs sleep to restore itself. Sleep allows cells to repair, grow and regrow. This is supported by many important processes that happen during sleep, including tissue growth, hormone release, muscle repair, protein synthesis.
- Emotional well-being:
I bet you read that with a question in your mind: “Emotional well-being?”. Yes, Emotional well-being; when sleeping, brain activity increases in areas that regulate emotion, which including hippocampus, amygdala, insula, striatum and the medial prefrontal cortex.
The change in activity improves proper brain function and emotional stability. Take, for example, the amygdala which is in charge of the fear response. It controls your reaction when you face a perceived threat, like a stressful situation. When you get enough sleep, the amygdala can respond more adaptively. But if you’re sleep-deprived, the amygdala is more likely to overreact.
What happens when you sleep?
To take advantage of our rest, both the amount and the quality of sleep are significant. Teenagers need in any event 8 hours—and on regular 9¼ hours—a night of continuous rest to leave their bodies and brains revived for the following day. Sometimes our rest is stopped, and at those times the body does not get the opportunity to finish the entirety of the stages required for muscle fix, memory union and arrival of hormones managing development and hunger. At that point, we wake up less arranged to focus, decide, or connect completely in school and social exercises.
There are four stages of sleep which your body cycles through; this pattern repeats every 90 minutes. What this means is that stages will repeat about 4-6 times during a 7-9 hour sleep period.
The pattern includes three stages/phases of Non-Rapid Eye Movement (NREM) sleep and one phase of Rapid Eye Movement (REM) sleep.
The National Sleep Foundation classifies the sleep stages as follows:
NREM (75% of night): As we begin to fall asleep, we enter NREM sleep, which is composed of stages 1-4
- N1 (formerly “stage 1”)
This stage occurs when you first fall asleep. As your body enters light sleep, your eye movements, heart rate, and brain waves slow down. This stage lasts for about 7minutes.
- N2 (formerly “stage 2”)
This is the stage where you experience light sleep just before deep sleep. Your eye movements stop, your body temperature decreases, and your muscles and heart rate continue to relax. Your brain waves briefly spike then slows down. You spend the most time in stage 2.
- N3 (formerly “stages 3 and 4”)
At this stage, deep sleep begins. Your eyes and muscles do not move, and your brain waves slow down even further. Your body replenishes lost energy and repairs muscles, tissues, and cells. You need this stage to feel awake and refreshed the next day. Deep sleep is restorative
- REM Sleep (25% of night)
First occurs about 90 minutes after falling asleep and recurs about every 90 minutes, getting longer later in the night. In REM sleep, your eye movements and brain waves increase. Your breathing and heart rate also speed up. Dreaming often happens at this stage. The brain also processes information at this stage, making it essential for learning and memory.
How much sleep do you need?
The recommended amount of sleep varies from person to person. It is dependent on a person’s age, but the National Sleep Foundation suggests the following durations:
- Birth to 3 months: 14 to 17 hours
- 4 to 11 months: 12 to 15 hours
- 1 to 2 years: 11 to 14 hours
- 3 to 5 years: 10 to 13 hours
- 6 to 13 years: 9 to 11 hours
- 14 to 17 years: 8 to 10 hours
- 18 to 64 years: 7 to 9 hours
- 65 years and older: 7 to 8 hours
What happens if you don’t get enough sleep?
Your body has a hard time functioning properly if you do not get enough sleep. Possible consequences of sleep deprivation include early mortality, high blood pressure, fatigue, poor memory, insulin resistance, mood swings, poor motor function, chronic diseases (like diabetes and heart disease), depression, weakened immune system, anxiety, weight gain, poor focus and concentration.
In summary, sleep causes us to flourish by contributing to a healthy immune system. It can likewise adjust our appetite by assisting with managing levels of the hormones ghrelin and leptin, which assume a role in our feeling of hunger and fullness. So when we’re restless, we may want to eat more, which can prompt weight gain.
The 33% of our lives that we spend sleeping, a long way from being unproductive assumes an immediate job in how full, enthusiastic and fruitful the other 66% of our lives can be.