The Biology of Sleep and the Effects of Sleep Disorders
Sleep is a natural body process where the brain shuts the body down to restore levels for the next day. To most, sleep is an everyday or night occurrence. Often one will lay in bed and just fall asleep and wake in the morning disoriented and forgetting the last minutes of being awake. A good night’s sleep is something all wish for but only some can achieve on a natural basis. If you take a step back and think about it, you might wonder, what is sleep?
Although many have an accurate idea of what sleep is, an in-depth definition of the process is stated by Louise M. Patterson, “Sleep can be defined as a natural, periodic state of immobility where the individual is relatively unaware of the environment and unresponsive to external sensory stimuli” (Green, 2012, p. 18). This translates to a natural basis for a period in which the body is in a state of immobility where the person is mostly oblivious to the happenings of the environment and insensitive to worldly sensory stimuli. This rest cycle occurs for an approximated one third of a day and an approximated one third of our lives.
The body has a natural internal clock that controls the cycles of sleep and alertness within the body’s natural regular intervals called circadian rhythm. Also called the sleep/wake cycle, circadian rhythm is controlled by the hypothalamus in the brain. The National Sleep Foundation explains how this cycle works when one is ready to sleep, “When it’s dark at night, your eyes send a signal to the hypothalamus that it’s time to feel tired. Your brain, in turn, sends a signal to your body to release melatonin, which make the body tired” (What is Circadian Rhythm, 2019). This rhythm can be affected by daylight savings time, jet lag, or staying up late into the night which makes it harder for one to pay attention and will may cause the feeling of being out of sorts (What is Circadian Rhythm, 2019).
Sleep consists of four essential stages. These stages were put into effect based upon the different wave frequencies occurring inside the brain. The first three stages are all non-REM sleep. Stage one of the cycle is essentially the first stage most go to when first nodding off. As stated by the National Institute of Neurological Disorder and Stroke (2019), your body changes from wakefulness to sleep, the movements of the heart, lungs and eyes slow and the muscles partially relax in this first stage of light sleep. The brain waves too change from awake to sleep. Stage two is still considered a light sleep but the body continues to slow. (Brain Basics: Understanding Sleep, 2019). The heart and lungs progressively slow and the muscles continue to relax.
Along with these changes, the eye movements cease and the body’s temperature drops. Brain activity continues to slow with minor periodic electrical burst. This means that the brain is still “awake” even if it is minimally. Through this stage comes the next, advancing into a deeper sleep. Stage three consists of slower brain waves causing deep sleep where one is not easily wakened (Brain Basics: Understanding Sleep, 2019). Although the brain never sleeps, the slower brain waves constitute in more methodic and calming rhythms for sleeping to occur. The muscles fully relax, and the breathing and heart rate are declined to the lowest levels. (Brain Basics: Understanding Sleep, 2019) The fourth stage or REM sleep will be discussed later.
While the need for sleep is becoming a more common study because of the lack of information, some research has theorized why we complete this cycle. Dr. Neil B. Kavey, Sleep Disorders Center at Columbia-Presbyterian Medical Center director, gives some clues as to the necessities of this common function, “..we think it restores the body’s energy supplies that have been depleted through the day’s activities” (Kavey, 2013). As the body moves and completes tasks during one’s daily lives, the energy storage slowly lessens, causing the body to feel more tired as the day goes on. Kavey (2013) also comments on the muscle tissue that is rebuilt like the growth hormones secreted while asleep and the importance of rebuilding these tissues especially through adulthood. While the specific functions of sleep are still being test and retested, more and more reasons to get a good, healthy amount or sleep is becoming obvious.
To feel truly refreshed when one wakes from sleep, some need a solid eight hours of sleep while some might be fine with five or six and an occasional day nap. The proper amount of sleep for the health of the individual is eight hours as many hear through the days. While this may seem like a lot of sleep to some this is the minimum for adults and younger children need much more. An article named Healthy Sleep (2019) writes the hours of sleep each stage of life should be receiving. Newborns should receive seventeen hours, preschool-aged children should receive twelve, school-aged should receive ten, teens should sleep around nine to ten and adults should receive seven to eight for healthy mental and physical health (Healthy Sleep, 2019).
Getting the proper amount of sleep is not only important for health reasons but also for everyday situations. Jeffery S. Nevid (2015) explains the effects of sleep deprivation. Nevid (2015) writes that sleep deprivation, “makes it more difficult to concentrate and pay attention, respond quickly, solve problems, and to remember new information.” Sleeping helps restore energy levels and without these levels restored concentrating and paying attention could seem like a wasteful task when compared to staring off or taking a nap. Responding quickly, remembering information, and solving problems are affected because of the brains will to continue restore and not having your body at peek alertness. Nevid (2015) also explains how sleep can affect the immune system. He explains, “you may find yourself more susceptible to the common cold and other physical health problems when you’ve gone without your necessary quota of sleep” (Nevid, 2015, p. 147). Getting the right amount of sleep has very good benefits but some are not able to properly get the amount of sleep naturally.
While some just lay on their pillow and drift to sleep, many have difficult troubles falling asleep or staying asleep. Two common sleep disorders are insomnia and sleep apnea. While there are many sleep disorders these are some of the most common and straining on mental and physical health. Insomnia, stated by the National Sleep Foundation (2019), is characterized as a disorder with difficulty falling or staying asleep. Many struggle for hours tossing in turning to try and get their body to rest and others sleep for short increments, causing sleep deprivation. Some of the symptoms associated with insomnia are low energy, fatigue, mood disturbances, difficulty concentrating, and decreased performance in work or school (What is Insomnia, 2019).
Insomnia can cause many issues for many both mentally and physically. Sleep apnea can also cause these issues. Sleep apnea is a potentially more dangerous sleep disorder because, as Mayo Clinic (2019) explains, “breathing repeatedly stops and starts.” This lack of oxygen can cause many problems to the health of the body. Some complications are daytime fatigue, decreasing in blood oxygen levels cause high blood pressure and heart problems, insulin resistance or Type 2 diabetes, and other very serious medical issues (Sleep Apnea, 2018). Sleep disorders are very serious not only to the physical health of the body but also the mental health of the someone who wishes to sleep peacefully but can not achieve so.
When one goes to bed, a mother might kiss them goodnight and tell them to have, “sweet dreams” before shutting off the light. We normally correlate a good sleep with nice dreams. This stage in which we dream is the fourth stage of the sleep cycle as mentioned earlier. As mentioned before, through the stages of sleep, the body’s processes slow including breathing, eye movement, and the muscles relaxing. During REM sleep or the fourth stage, the pattern of bodily processes shift and begins to accelerate. Cleveland Clinic tells about these drastic changes in the physiological processes, “REM sleep is marked by extensive physiological change: accelerated respiration, increased brain activity, eye movement, muscle relaxation” (Sleep Basics, 2019). This stage more closely relates to stage one because of the activity of all the different bodily processes. REM sleep is also unusual because of the heightened brain activity and simultaneous paralysis. These two processes together combine and allow one to dream. The increased cerebral activity allows for mild to intense dreams while the paralysis combine to the groups of voluntary muscles constitutes a safe dreaming scenario allowing the body to remain still and not act out the dream.
The most unique aspect to REM sleep is dreams. Psychology Today tells us, “Dreams are the stories the brain tells during sleep-they’re a collection of clips, images, feelings, and memories that involuntarily occur during the REM stage of slumber” (Dreaming, 2019). These mental clips, images, etc. then form together to tell a progressive storyline some of which have absurd aspects. While some dreams may seem so comical that you would remember it when awoken, many recall not remembering the dream experienced. These dreams also often have aspects of memory taken from everyday life such as familiar people and locations (Dreaming, 2019). Although dreams are a common occurrence, researchers are still unsure of the basis that dreams lie upon. Psychology Today (2019) gives an explanation to the research done in past years, “Though it’s been discussed and studied for millennia, it remains one of behavioral science’s greatest unanswered questions.” One should expect to see more research completed in the future on this topic.
While some may giggle at the contents of their dreams, some do not acquire the pleasure of sleeping with a harmless dream. Nightmares, as explained by WebMD are, “vivid nighttime events that can cause feelings of fear, terror, and/or anxiety” (Sleep Disorders and Parasomnias, 2019). These terrors often cause one to awaken sometimes even abruptly or violently. Once one is awakened by these nightmares, they are often unable to fall back asleep which may lead to cases of insomnia.
Another disorder that can affect people of all ages is sleepwalking. WebMD gives a definition to the disorder, “Sleepwalking occurs when a person appears to be awake and moving around but is actually asleep” (Sleep Disorders and Parasomnias, 2019). Sleepwalking is typically harmless. Some report waking up in their kitchen or some do not even recall walking at all.
Sleep is a common occurrence of all people that naturally occurs according to the circadian rhythm. When we sleep the body restores spent energy and reduces the rate at which our body functions. Sleep is a natural process that we all need for proper mental and physical health.
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