Sleep: What It Is and Why It’s Important
Sleep is important, and there’s no denying it. Regardless of the amount you typically get, not sleeping is the equivalent of neglecting your bodily needs. Let me start off with a story from my 8th-grade year, and feel free to think of your own responses to the questions my teacher is about to ask:
During a class, a teacher calls on a student and asks them this question: “What time do you typically sleep?”
The student responds with, “Around 12 A.M., but it depends on my homework and other commitments I’m doing.”
The teacher pauses for a moment, then asks another question: “You sleep from 12 A.M. to [roughly] 6:30 A.M., meaning you get 6.5 hours of sleep. Let’s say school was delayed by two hours, meaning that school starts at 10 A.M. instead of the typical 8 A.M. What time would you sleep then?”
The student then answers, “I’m not sure, but I would sleep much later than 12 A.M. Maybe 2 A.M. if I wanted to.”
Finally, the teacher mentions this to his class:
“Despite having a delayed opening, you’re still getting the same 6.5 hours of sleep. You’re not ‘sleeping in,’ when you have a delayed opening. You’re given the opportunity to sleep for a nice 8.5 hours, and yet you complain about wanting more sleep all the time. The school has obviously given you the opportunity to sleep more, but you don’t take it. Why?”
What Is Sleep Like?
Sleep is difficult to define, as it continues to be a vague topic that still perplexes many scientists. Although it’s usually characterized by deep consciousness and limited bodily activity, I like to characterize sleep as a maze.
Mazes are not only confusing, but each individual pathway is accompanied by a various number of different directions. What makes mazes so enigmatic is similar to the mysteries of sleep. While there are several stages where almost every individual experiences the same bodily actions, certain people might spend longer times in each stage (which relates to the many ways that one can escape from the maze). In such a way, sleep can be a subjective matter with respect to what each person goes through, and it can be a probable explanation for why discovering newfound conclusions about sleep is difficult.
Sections of the Brain Involved in Sleep
The hypothalamus is a somewhat small structure located in the deeper regions of the brain, and it’s responsible for controlling our sleeping/arousal periods. It has a group of neurons called the ventrolateral preoptic neurons (VLPO), which connect to arousal-promoting centers and inhibit their activity during deeper stages of sleep. Inside the hypothalamus is a large cluster of neurons called the suprachiasmatic nucleus (SCN), where information about light exposure to the eyes is read and our sleep/wake cycle is controlled. The hypothalamus is necessary to allow our bodies to remain dormant during sleep, rather than being constantly awoken.
While the hypothalamus controls the sleeping/arousal periods, the brain stem (located at the bottom of the brain) is connected to the hypothalamus and controls the transitions between sleeping and awakening. Through sleep-promoting cells within the brain stem and hypothalamus, a chemical called GABA is produced that controls the activity of arousal centers. In addition, the brain stem also sends signals to our muscles during REM to prevent individuals from acting out their dreams and potentially hurting themselves.
While the thalamus is typically responsible for controlling our sensory/motor signals, it quiets during NREM sleep to prevent connections with our external world. However, the thalamus becomes extremely active during REM sleep to provide the sensations we feel during vivid dreams.
The pineal gland is connected to the brain’s SCN and, based on its readings, fluctuates the production of the hormone melatonin. In a dark environment, the body’s high production of melatonin is what causes you to feel drowsy (unfortunately, this pertains to me when my teacher turns the lights off in their classroom to show the class a PowerPoint presentation).
The basal forebrain typically produces a chemical called acetylcholine, which promotes REM sleep and wakefulness. Although the production cycle of this chemical continues to remain misunderstood, scientists have discovered the inhibition of this chemical results in slow-wave sleep.
The amygdala is extremely active during REM sleep and controls our emotional responses to both actions that occur in our dreams and the period after we experience the dream.
Stage 1 (NREM): Light Sleeping
Stage 1 of our sleep cycle occurs for roughly 5–10 minutes and is the lightest sleeping stage in the entire cycle. Considered a transition between being awakened and truly asleep, people that are woken from this stage might believe they weren’t truly sleeping. During this section of sleeping, the brain switches from producing traditional alpha to theta waves, which are slower and have a larger amplitude. The production of theta waves in the brain causes our bodies to lose touch with our external environment and begins controlling signals from within ourselves.
For example, individuals in Stage 1 might experience arbitrary muscle jerks and a falling sensation, which is the primary reason it’s a gateway between consciousness and sleep. The “feeling of falling” previously described is referred to as hypnic myoclonia.
Stage 2 (NREM): Somewhat Light Sleeping
Adults can spend as long as 50% of their sleep cycle in Stage 2, which is still considered light sleeping but is significantly deeper than Stage 1. During this stage of our sleep, heart rate begins slowing down and one’s core temperature will begin decreasing. While your eye movement does stop and the muscles relax further, your brain (still producing theta waves) will output short bursts of brainwaves called spindles. These “spindles” are responsible for random muscle twitching and the refreshment of our memories.
Stage 3 (NREM): Extremely Deep Sleeping
While adults spend roughly 20% of their sleep cycle in this stage, infants spend a whopping 50% of their sleeping time in the deepest stage of NREM sleep. Our blood pressure continues to lower along with heart rate and body temperature during this stage. Although the body is rendered immobile in this stage, the muscles are still somewhat functional and contribute to many actions performed by children (bedwetting, sleepwalking, nightmares, etc). The brain then switches from the production of theta to delta waves, which are even slower and further reduce contact with one’s external world.
A majority of the body’s repairments occur during Stage 3 of sleeping, such as hormone production and appetite regulation. People that are woken up while in Stage 3 of their sleep cycle will be disoriented and groggy for several minutes due to their extreme lack of connection with their surroundings.
Stage 4: REM Sleep
REM (rapid eye movement) sleep typically occurs around 90 minutes after falling asleep. This stage of sleep is where breathing and heart rate become extremely erratic and irregular, and the brain is significantly active during REM, which causes us to experience vivid dreams. The body is also temporarily paralyzed (not to be confused with sleep paralysis, this condition is still present when the affected individual is also conscious), which makes this stage somewhat paradoxical since the brain becomes increasingly active.
Why Is Sleep Important?
“It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it.” — John Steinback
Sleep is necessary for a multitude of reasons, and here are a few:
Sleep allows for your memories to become refreshed and helps the body to rejuvenate itself, which includes the regulation of hormone production and appetite. If you are unable to reach Stage 3 of the sleep cycle (which is usually caused by sleeping much less than the recommended 8 hours), you will likely wake up groggy, disoriented, and even irritable and moody.
This is caused by the body’s failure to regulate hormone production, which is typically done during the later stages of NREM sleep. By sleeping for around 8 hours on a daily basis, your body has able to time to regulate itself and will leave you waking up completely refreshed. For example, a study found that individuals with poor sleeping habits displayed similar behaviors to that of alcohol intoxication, which doesn’t sound pleasant!
In addition to repairing the body and controlling hormonal production, our sleep cycle is also responsible for controlling appetite. Sleeping well is commonly linked to a more controlled appetite, which indicates that these individuals will eat fewer calories.
However, poor sleeping habits will affect your appetite negatively and even transform it into something voracious, which leads to higher calorie consumption and ultimately, weight gain. In a review study, children and adults that demonstrated poor sleeping habits were 89% and 55% more likely to develop obesity, which are some staggering numbers!
Well-controlled sleeping habits allow for the brain to refresh itself repeatedly and consolidate all memories together. A lack of sleep, therefore, is commonly associated with a disoriented stature and an inability to remain productive throughout the day. The increased severity of such conditions is linked to a multitude of mental conditions, including depression and anxiety.
A statistic revealed that 90% of individuals with depression have frequently complained about their poor sleeping habits.
Sleep is responsible for controlling your mood, which is strongly linked to an individual’s social interactions with others. With a mood that’s less pretentious and unlikeable, better sleeping habits will allow for smoother interactions with other people.
One study discovered that people with neglectful sleeping habits failed to recognize the critical emotions of other individuals, such as anger and happiness.
- Sleep is a period of deep consciousness that is split into several stages, each with its own characteristics.
- Sleep is critical for the human body because it: boosts one’s mood, improves weight control, prevents mental conditions, and improves social interactions with others.