The Functions of Sleep
FUNCTIONS OF SLEEP:
Sleep has not one main function but many.
A most popular theory on why we sleep is the restorative theory of sleep:
Restorative Theory: the theory of sleep that states that we sleep in order to replenish the processes of our minds and bodies that are depleted during the coarse of everyday life.
Increases in low wave sleep correlate with increases in physical activity
During REM sleep, proteins and other cellular components are returned to body
But is the restorative theory valid?
"Second Wind Phenomenon," the fact that people's sleepiness disappears when they have not slept counters the restorative theory.
Studies have shown that napping or just resting in bed are equally capable of improving mood.
During Sleep: blood flow in the cerebral arteries is elevated, heart and respiration become irregular, brain activity is elevated in certain areas.
Another function of sleep is the Adaptive Non-responding Theory:
Adaptive Non-responding Theory: the evolutionary theory of sleep that suggests that sleep and inactivity at night have survival value.
Most recently (1988) Wilse Webb, one of the leading researchers on sleep for over 30 years has suggested a theory that combines the best explanatory features of the restorative and adaptive Non-responding theory.
Webb suggests that sleep is a function of sleep demand, circadian tendencies, & behaviors that promote or inhibit sleep.
BIOLOGICAL RHYTHMS AND ALERTNESS:
Our biological clocks allow us to keep time in a changing world.
Circadian Rhythm: internal biological rhyth...
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... (1) sleep attacks; (2) cataplexy-sudden loss of muscle tone; (3) sleep paralysis; & (4) auditory, visual, or tactile hallucinations.
SIDS (Sudden Infant Death Syndrome): during sleep, a sudden inexplicable death of an infant who has been in perfectly good health.
Sleep Apnea: a rare sleeping disorder in which the person stops breathing momentarily.
Characteristically sufferers of sleep apnea are male, overweight, have high blood pressure and will experience fatigue, morning headaches, sleepiness and loss of memory but mainly FEAR of death in the night.
Somnambulism: sleep walking occurring during stage 4 sleep that usually involves repetitive acts performed while asleep that are not recalled once the person wakes.
Sleep Talking: talking occurring stage 1 of sleep, when a person is "half asleep and half awake."
Sleep is one of our basic needs to survive, however in the modern days sleep deprivation in increasing more and more each day, causing accidents and medical problems for the people and the community. This essay will look at the meaning of sleep and sleep deprivation and the basic perspectives on what motivates sleep and sleep deprivation with the five perspectives; evolutionary, psychodynamic, behaviourist, cognitive and the hierarchy of needs. This essay will also evaluate the best perspective to eliminate sleep deprivation with the cases studies discussing the general hypothesis of sleep and sleep deprivation.
The symptoms of narcolepsy include cataplexy, persistent daytime sleepiness, sleep paralysis, and hypnagogic hallucinations. Cataplexy is “a loss of skeletal muscle tone without loss of consciousness” (77). These cataplectic attacks often occur at emotional times. Such events could be laughter, sexual intercourse, physical exertion, and anger. Daytime sleepiness can make narcoleptics fall asleep at inappropriate times and although they may be refreshed after naps they are soon tired after. Sleep paralysis is the inability to move prior to falling asleep or waking. Finally, hypnagogic hallucinations are vivid dreams before sleep or when extremely tired.
is the transition between light sleep and very deep sleep.Stage four is sometimes referred to as
We live our entire life in two states, sleep and awake1. These two states are characterized by two distinct behaviors. For instance, the brain demonstrates a well-defined activity during non-REM sleep (nREM) that is different when we are awake. In the study of sleep by Huber et. al., the authors stated that sleep is in fact a global state2. It is unclear whether this statement means that sleep is a state of global behavioural inactivity or the state of the global nervous system. The notion that sleep is a global state of the nervous system served as basis for sleep researchers to search for a sleep switch. The discovery of the sleep switch, in return, provided evidence and enhanced the notion that sleep is a global state of the nervous system. The switch hypothesis developed from the fact that sleep can be initiated without fatigue and it is reversible1. It was hypothesized that there is something in the brain that has the ability to control the whole brain and initiate sleep. Studies have found a good candidate that demonstrated this ability3. They found a group of neurons in the Ventrolateral Preoptic (VLPO) nucleus. It was a good candidate because it was active during sleep, has neuronal output that can influence the wakefulness pathway, and lesion in the area followed reduce sleep3. The idea that there is something that can control the whole brain and result sleep state supports the idea that sleep is a global state of the nervous system.
Sleep is an extremely interesting phenomenon in which the mind almost completely departs from the usual realm of consciousness. It is distinguished from quiet wakefulness and a decreased ability to react to stimuli where we become less aware of our surroundings. However, it is more easily reversed than being in hibernation or a coma. It is a function that has been extensively researched by many. After all, we would not have evolved a mechanism that forces us to spend one-third of our lives sleeping unless sleep did us some good. What good does it do tough? Over the years, many theories have been proposed as to why we need sleep. The simplest is that it saves energy. An individual’s energy expenditure and demand is reduced during the day, or night, as an animalistic instinct when they are least efficient to search for food. This is also supported by the decrease of body temperature and caloric demand throughout sleep. For example, when NASA sent a robot to mars, it was programmed to shut down at night so exploration would not waste energy. This is like our bodies, as they need time to recuperate and to slow down. In addition, sleep provides an occasion for restorative functions of the brain where the body is allowed sufficient time to repair and rejuvenate itself. For example, animals that are deprived of sleep entirely lose all their immune function and will soon die in a matter of weeks. Other findings have shown that many restorative functions in the body like tissue repair, muscle growth, and growth hormone occur mainly during sleep. When people are deprived of sleep, inhibitory transmitters accumulate in the brain, interfering with attention and learning. People that are well rested will notice when their attention lapses, a...
Sleeping is a complex process that greatly affects an individual’s well-being. There exists within each person a natural body clock which allows one to operate at a 24 hour cycle. In relevance, the body clock iswhat instinctively determines the cycle of sleep and awake time of a person. This relates to sleep because the issues that affect one’s body clock has a connection ...
Sleep is a reoccurring act that is part of our daily lives. It is one of the most important elements of human health. The natural state of sleep has been studied throughout the years of human evolution. It occurs when hormones are released throughout the body to make the individual begin to fall asleep. The importance of sleep is often overlooked amongst humans, leading to a disorder. There are problems that occur in the human body that are of higher importance and require more attention. Sleep disorders should be viewed as a priority to humans because it alters human health, presents as a precipitating factor for other health problems, and can be treated quickly.
muscles loosen, and blood pressure falls. During stage four the sleeper is in a deep sleep
Division of Sleep Medicine at Harvard, . "Why do we sleep anyway?" Healthy Sleep. WGBH Educational Foundation, 2008. Web. 10 Apr. 2014.
Why we need sleep is an unanswered question that even scientist don’t know the exact answer too. But, they do know what will happen to you without s...
Sleeping is something that is an essential part of human nature and is a must in order for one to be a functional human being. Sleep is an idea that is accompanied by many wives’ tales, including the ideas that one needs seven to eight hours of sleep each night and alcohol helps one fall asleep and sleep more soundly. One myth about sleep is that during sleeping, one is in a state of nothingness. In truth, however, it has been discovered that during sleep the brain is active, variations in heartbeat and breathing occur, and the eyes and ears are active throughout the time of sleep. These activities during a person’s sleep are important because they help that person be more aware, awake, and alert during consciousness. If all of these important activities occur during sleep, why is it that people are so willing to short themselves of this vital activity? Although much about sleep still remains a mystery, research and experiments continue to show how important sleep is to each and every person. Throughout this paper, I will discuss sleep and the effects that it has on performance and health, especially in college students. A college student’s sleeping pattern is a reliable indicator to their level of performance in the classroom and other school-affiliated activities, as a lack of sleep leads to decreased performance. Sleep is directly related the level of performance and health in an individual; the more rested a person is, the better that person will perform and feel (Dryer, 2006).
Kales, A. (1972). The evaluation and treatment of sleep disorders : Pharmacological and psychological studies. In M. Chase (ed.)The Sleeping Brain. Los Angeles : Brain Information Service.
Cauter, Eve Van. “Science of Sleep.” CBS News. 60 Minutes, 15 June 2008. Web. 6 Mar. 2014
Important public policy issues have arisen in our modern 24-hour society, where it is crucial to weigh the value of sleep versus wakefulness. Scientific knowledge about sleep is currently insufficient to resolve the political and academic debates raging about how much and when people should sleep. These issues affect almost everybody, from the shift worker to the international traveler, from the physician to the policy maker, from the anthropologist to the student preparing for an exam.
Many studies of the role of sleep are partial or total sleep deprivation studies which support Oswold’s restoration theory. One of these supporting studies was Dement’s. He deprived participants of REM sleep and consequently found that they increased their number of attempted REM stages from 12 to 26 over 4-7 nights. During their first uninterrupted night, participants increased their REM sleep by 10% which is known as REM rebound. This suggests the importance of REM and the possibility that the purpose of sleep is to get into REM sleep. The participants reported anxiety, irritability and difficulty concentrating which shows that REM sleep is needed to avoid these affects and enable brain recovery which corresponds with Oswold’s theory. Even so, Dement’s study has low ecological validity, it has low population validity because there were only 8 participants and they were a self-selected sample. Participants would probably have shown demand characteristics because the experiment took place in a lab. It also has low mundane realism because people would not usually sleep in a lab and be interrupted repeatedly.