The Science Behind Why We Sleep

Sleep is an indispensable part of human life. People spend about a third to a quarter of their lives sleeping. A past belief is that sleep is a period during which the mind and body go dormant. However, it is now evident that sleep is a time during which your brain engages in several activities essential for your wellbeing.

Sleep is vital for cognitive functions. Your brain leverages on sleep time to solidify and consolidate your memories. As you maneuver your day, your brain consumes large amounts of information. Your brain does not process this information as it receives it; this happens during the night when you sleep.

During sleep, your brain processes and transfers this information from the short-term memory to the more robust long-term memory via a process termed consolidation. Research indicates that people tend to recall information and handle memory tasks better after they sleep. Your body tissues need quality sleep for them to recover, rejuvenate, grow repair, and carry out metabolic processes.

Mechanism of sleep

Two biological processes regulate sleep and wakefulness; they are Circadian rhythm and sleep drive.

  • Circadian rhythm:

A biological clock in the brain controls the circadian rhythm. The circadian rhythm regulates the changes in the state of sleep, body temperature, and secretion of hormones. The rhythm responds to light clues increasing the secretion of the melatonin (a hormone) at night and lowering its production during light hours. Persons with blindnesss often experience problems with sleep because they cannot perceive and respond to the changing light signals. The circadian rhythm, like a clock, has twenty-four-hour repeating cycle.

  • Sleep-wake homeostasis/sleep drive

This homeostasis monitors your body’s need for sleep and causes you to sleep after a given period. Your body desires sleep increases as your progress the day to culminate in sleep. When you are tired sleep drive can cause to sleep irrespective of your environment (meeting, party, driving). Sleep drive influences the intensity of sleep. You will experience a longer and deep sleep after a prolonged period of sleep deprivation.

What happens when you are asleep?

Sleep occurs in repeated cycles with each lasting for 90 to 110 minutes. Each cycle has two phases – the REM (rapid eye movement) and non-REM cycles.

  • Non-REM Sleep: 

Non-REM Sleep occurs in four stages:

  • Stage one:

This is also the light sleep stage where your body is transitioning from wakefulness to sleep. This is a short period lasting several minutes. You experience relatively light sleep, your breathing, eye movements, brain waves, and heartbeat slow. Your muscles relax, and you may experience occasional muscle twitches. You are in light sleep, and any disturbance can awaken you quickly.

  • Stage two:

This is the true sleep phase that lasts for about twenty minutes. Your body goes into a light sleep. Your breathing pattern and heartbeat slow down. The muscles relax further, and eye movements cease. Your body temperature falls, and brain activities slow. You spend a large chunk of your sleep time in this stage.

  • Stage three:

This is the stage of deep sleep. It occurs in extended periods in the initial half of the night. Your heart rate and breathing rate fall to their lowest during this phase. Your brain produces delta waves, which are slow and characterized by high amplitude and low frequency. Your muscles relax. It is difficult to awaken you during this phase.

  • Stage four:

Your body is in a deep sleep. There is minimal muscles activity, and your body experiences rhythmic breathing. If awakened during this stage, it will take you several minutes to adjust. You will feel sleepy and disoriented for some minutes. Some kids wet the bed or experience sleep walking during this stage.

  • REM sleep

This stage starts about seventy to ninety minutes after you fall asleep. Although you are unconscious, your brain is very active; almost as active as during the wakefulness period.Your eyes move fast from side to side behind shut eyelids (hence the name Rapid Eye Movement). Your breathing rate rises and becomes irregular while your heart rate increases to near that of wakefulness. A lot of your dreams occur during the REM phase. Your body goes into temporary paralysis, which is nature’s way of stopping you from acting on dreams.

Your body cycles through all stage of non-REM and REM severally during the night. The REM periods continuously become longer and deeper towards morning. You may cycle four to five times on your typical nights.

8 reasons your body needs sleep

Sleep is necessary for good health and wellbeing of your life. Quality and sufficient sleep at the right time enhance your mental health, physical health, safety, and quality of life.

  • Sleep has a substantial impact on how your brain functions:

This explains why you feel foggy during the day after experiencing poor sleep at night. Healthy sleep is essential to enhance your brain’s ability to take in new information. Insufficient sleep will hamper your learning process, and you will experience trouble remembering it in the future. Quality sleep improves your learning and enhances your problem-solving ability. It increases your attentiveness, creativity, and ability to make decisions.

  • Sleep is essential for your emotional health:

If you lack sleep, you will experience problems in controlling your emotions and behavior. Poor sleep aggravates the symptoms of conditions such as depression such as suicide and risky behavior. Sleep-deprived children and teens have problems interacting with others. These kids may feel angry, impulsive, experience mood swings, and lack motivation. Deficient sleep impairs the kid’s attentiveness, and that is why they may get low grades leading to stress.

  • Sleep is vital for your physical health:

Your body repairs its tissues during sleep. Research shows a link between prolonged sleep deprivation and elevated risk to conditions such as heart disease, high blood pressure, and diabetes. Sleep deficiency increases the risk of becoming obese.

  • Sleep is crucial for your body defenses:

Lack of sufficient sleep exposes your body to health risks. Poor sleep aggravates the symptoms of conditions such as migraines, depression, high blood pressure, and seizures.

  • Sleep promotes healthy growth and development in kids:

Quality sleep enhances the production of growth hormones in kids, which ensures they grow normal. The same hormones promote the development of muscles, repair of damaged cells, and tissues across all ages.

  • Sleep is vital for your body defense system:

Quality sleep is essential for a healthy immune system. Sleep deprivation will impair your immunity. A compromised immune system will expose you to the risk of common infections.

  • Quality sleep means improved performance throughout your day:

Those who experience sleep deprivation are often less productive at school and work. Low production means you take longer to finish a task, and your response is slower than usual. You are also prone to make more errors.

  • Sleep affects your safety:

Sleep deprivation may cause you to experience microsleep. This means you experience short moments of sleep during your regular time of wakefulness. You are often when aware when microsleep strikes and controlling it is very difficult. If you are working with dangerous machines or driving, microsleep can lead to grave accidents. Sleep lapses can also cause slips, falls, and even medical errors. Aside from accidents, you will miss out an important information if it happens during a meeting or a lesson.

How much sleep do you need?

Sleep is vital. However, how much of it do you require?  There is no set standard number of sleep hours by which each person should abide. The hours of sleep vary with individuals and age. Young children require more sleep time to allow for growth and development. For example, newborns need more than sixteen hours each day while school-aged kids often take naps during the day. Most people fall in the bracket of five to eleven hours of sleep. However, most healthy adults sleep anywhere between eight and nine hours a day.

The best approach is to have enough sleep such that you do not get sleepy during the day. Due to prolonged work hours and entertainment, many people fail to get sufficient sleep. Many believe they can accumulate sleep deprivation and recover the “sleep debt” during the weekend. Unluckily, you cannot sleep for fewer hours throughout the week and hope to recover by sleeping for many hours during the weekend. Stick to a healthy sleep routine that lets you meet your sleep requirements each night.

How to get a good night sleep

  • Quality and sufficient sleep are vital to your health. Here are some helpful tips to improve your sleep.
  • Avoid stimulants (caffeine and nicotine) in the late hours of the day.
  • Shun alcohol and alcoholic drinks before bed.
  • Relax before going to bed – have a relaxing routine such as reading a book or taking a warm bath.
  • Have a schedule – Set sleep and wake time that you will adhere to each day.
  • Avoid staying in bed awake – If you are not sleepy, try a book, and listen to music or something relaxing until you are tired.
  • Create an ambient environment for sleep. You need a dark room, no loud music, and a comfortable temperature. Avoid watching TV or staying on your computer immediately before sleeping.
  • Exercise for about thirty minutes each day (Make sure it is some hours before bedtime – do not exercise and go to bed immediately).

Too much sleep is not good

The number of sleep hours one needs varies from one person to person. Yes, sufficient and quality sleep is good. However, if you sleep for more than nine hours a day, you are harming your body. People who sleep for extended periods risk circulatory problems. Calcium may accumulate in their heart and arteries and cause the arteries to lose flexibility. Seven to eight hours per day is enough sleep time for a healthy adult.