Five stages of sleep!
Noah Bratcher
In partial fulfilment of the requirements for
Eighth Grade Science
Cub Run Elementary
Matt Hawkins, instructor
2/28/14

Abstract over stages of sleep
This research paper provides a brief overview of stages of sleep. Humans spend about one-third of their lives asleep. There are two types of sleep, non-rapid eye movement sleep and rapid eye movement sleep. Sleep is divided into five stages. Each has unique characteristics
including variations in brain wave patterns, eye movements, and muscle tone.

“The natural periodic suspensions of consciousness during which the powers of the body are restored compare REM sleep, slow-wave sleep.” All members of the animal kingdom must have sleep because sleep gives the brain a chance to reorganize data to help find solutions to problems and to process or recognize newly learned information and organize and archive memories.
Stage 1 sleep
Stage 1 sleep is experienced as falling to sleep and is stage between wake and sleep. It usually lasts between 5 and 10 minutes and occupies approximately 2-5 percent of a normal night sleep. This stage is dramatically increased in some insomnia (restless legs) and disorders that produce frequent arousals.
Stage 2 sleep
Stage 2 sleep is the baseline of sleep. This stage is part of the 20 minute cycle and occupies approximately 45-60 percent of sleep. Our brain begins to produce rapid, rhythmic brain wave activity. Body temperatures drop and heart rate start slowing down.
Stage 3 sleep
Deep, slow brain waves known as delta waves begin to emerge during stage 3 sleep.
Stage 3 is the first stage of deep sleep. The brain waves are a combination of slow waves, known as delta waves, combined with faster waves. During stage 3 sleep it can be very difficult to wake someone up. If you are woken up during this stage, you may feel groggy and disoriented for several minutes.

Stage 4 sleep
Stage 4 sleep is the second stage of deep sleep. In this stage the brain is making the slow delta waves almost exclusively. In this stage it is also very difficult to wake someone up. Both stages of deep sleep are important for feeling refreshed in the morning. If these stages are too short, sleep will not feel satisfying. Sleepwalking and bed-wetting happen towards the end of this stage.
Stage 5 sleep: REM
Most dreaming happens in this stage, known as REM. REM characterized by quick, random eye movements also paralysis of the muscles. The amount of time spent in REM depends on your age. When you enter into REM sleep, your breathing becomes fast, irregular and shallow. Heart rate and blood pressure increase. About 20 percent of sleep is REM sleep for adults.
This sleep phase begins about 70 to 90 minutes after you fall asleep. The first sleep cycle has a shorter phase of REM sleep. Toward morning, the time spent in REM sleep increases and the deep sleep stages decrease. People usually experience this stage about 4 to 5 times a night.
The amount of time one spends in REM sleep has a lot to do with certain psychological factors - people with depression are in this stage for a shorter time than those without it.
Children spend more time in REM sleep than adults. Studies have shown that people who go to sleep after being sleep deprived enter REM sleep faster. While in REM sleep, most of the

muscles become paralyzed and the activity of the brain's neurons becomes quite intense, similar to the activity during wakefulness.
REM Dreams and Non-REM dreams are very different from each other in a ways. The first difference between the two is Non-REM dreams consist of fragmentary impressions. They are also less likely to involve visual images and are more frequently forgotten. Non-REM dreams are like thinking about something during the day for a short period of time while REM dreams are comparable to thinking deeply about something.
Why do we dream?
A new study says that, dreaming may act like a type of overnight therapy, taking the edges off painful memories. In some experiments, brain scans of people who viewed emotional pictures and then went to sleep showed that the emotion part of the brain shut down during
REM sleep.
Why do we sleep?

Scientist have explored that question from many angles. They have examined, for example, what happens when humans are deprived of sleep? In other studies, they have looked at sleep patterns in variety of organisms to see what is similar and different among different species might reveal something about functions of sleep. Yet, despite years of research and many discoveries about different aspects of sleep, the question of why we sleep is really hard to answer.
The lack of clear answers to this hard question does not mean that research has been a waste of time. In fact, we now know a lot more about why we sleep, and scientist have developed several promising theories of why we sleep.
Theory of why we sleep
Inactivity Theory
“One of the earliest theories of sleep, sometimes called the adaptive or evolutionary theory, suggests that inactivity at night is an adaptation that served a survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable. The theory suggests that animals that were able to stay still and quiet during these periods of vulnerability had an advantage over other animals that remained active. These animals did not have accidents during activities in the dark, for example, and were not killed by predators.
Through natural selection, this behavioral strategy presumably evolved to become what we now recognize as sleep.

A simple counter-argument to this theory is that it is always safer to remain conscious in order to be able to react to an emergency (even if lying still in the dark at night). Thus, there does not seem to be any advantage of being unconscious and asleep if safety is paramount.”
When you sleep, your body rests and restores its energy levels. However, sleep is an active state that affects both your physical and mental well-being. A good night's sleep is often the best way to help you cope with stress, solve problems, or recover from illness.
Sleep is prompted by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep, which consists of Stages 1 through 5.
During sleep, the body cycles between (NREM) and (REM) sleep. Typically, people begin the sleep cycle with a period of non-REM sleep followed by a very short period of REM sleep.
Dreams generally occur in the REM stage of sleep.
In conclusion, there are five stages of sleep that help our brain function. During sleep, the body has a chance to repair muscles, other tissues and aging or dead cells. Sleep helps are body tremendously by repairing a lot.
Works cited
• Dell'Amore, Christine. "Why Do We Dream? To Ease Painful Memories, Study Hints."
National Geographic. National Geographic Society, 29 Nov. 2011. Web. 16 Jan. 2014.

<http://news.nationalgeographic.com/news/2011/11/111129-sleep-dreaming-rembrain-emotions-science-health/>.
• Stages of Sleep | Psych Central." Psych Central.com. N.p., n.d. Web. 16 Jan. 2014.
<http://psychcentral.com/lib/stages-of-sleep/0002073>.
• Why Do We Sleep, Anyway?." Healthy Sleep. N.p., n.d. Web. 16 Jan. 2014.
<http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep>.
• "Why We Sleep." Why We Need to Sleep. N.p., n.d. Web. 7 Mar. 2014.
<http://www.sleepdex.org/sleep.htm>.
• "sleep." Merriam-Webster. Merriam-Webster, n.d. Web. 7 Mar. 2014.
<http://www.merriam-webster.com/dictionary/sleep?show=0&t=1394201825>.