The various circles of sleep take about eight hours to be fully completed. This paper analyses each night cycle, the period of time it takes, associated metabolic activities, transition to another cycle as well as the effect they cause to the body. These cycles fall in two major groups called Rapid Eye Movement (REM) and Non Rapid Eye Movement (NREM). The cycles of sleep examined include;
- The first stage
- The second stage
- The third stage
- The fourth stage, and
- The fifth stage
Different brain waves called alpha and beta waves are produced at different stages as later shown. This work further describes the sequence of occurrence of these cycles and the recommended time of sleep. Finally, the paper advises on the best time to wake up from sleep.
Scholars in the field of medical science and health carry out tremendous research about the topic healthy sleeping. This is in an attempt to establish the most appropriate time to sleep and the benefits derived from quality sleep. Scholars further establish the various night cycles that one undergoes while sleeping with their associated characteristics. History reveals that the Chinese Royal Family spearheaded the obsession for devising the best time to sleep prompting ancient Chinese scientists to lounge a study on the same. This research shows the time between 11pm and 1am as the most appropriate to sleep since it is the period when the body produces most regenerative and growth hormones. This guarantees better and quality sleep desired by the body. The sleep comes in five different stages described below.
This marks the beginning of sleep cycle lasting only for about 5 – 10 minutes. It forms transition from state of being awake to sleeping. Very slow high amplitude theta waves of about four to seven hertz are produced by the brain. The loss of muscle tone begins leading to hypnic jerks and twitches. At this juncture hypnologic hallucinations, colour patterns together with swirling light seduce one’s mind into restful sleep. Very light sleep characterizes this stage with ability to be woken by noise or loud music. In other words, the body prepares to shut down at this stage.
This forms the second stage of sleep lasting for about 10 – 25 minutes. Sleep spindles in the lower beta range of 12 – 16 hertz are produced by the brain that encompasses rapid, rhythmic brain wave. The heart starts beating at a slower rate and the body temperature reduces. Sleep paralysis occurs as nearly all muscles lose tone and hence the body cannot act out forthcoming dreams. Scientists believe half of the sleep is spent in this stage .
This marks the transition stage between light and heavy sleep. Brain waves called delta waves that are slow and deep in nature are produced. These waves now descend to delta range of 0.5 – 4 hertz, marking the slowest frequency ever experienced. There are no dreams at this stage, however most sleepwalking occurs at this stage. A person woken up at this stage feels confused and dopey for some minutes.
Delta sleep forms another name for this stage as a result of slow delta waves occurring. This is usually a deep sleep session lasting for about half an hour. Physical and mental energy replenishment occurs at this stage. Researchers argue that without such enough deep sleep one can never feel refreshed in the morning like when sleeping in a moving vehicle at night.
This is the last stage also referred to as rapid eye movement (REM) sleep. Increased rate of respiration, eye movement, and increased activity of the brain occur at this stage. The brain and other body systems get more active while the muscles get more relaxed. This phenomenon earns this stage a title of paradoxical sleep. Increased activity of the brain brings about dreaming. Brainwave activity resumes to the theta range (4-8 Hertz), through beta (12-38 Hertz). If woken up at this stage and returned to sleep then one dives back into this stage. Healthy brain functioning requires REM sleep for numerous reasons such as lasting memories. This stage comes up roughly 90 minutes after falling asleep. The initial cycle of REM stays only for a brief moment, but each subsequent cycle becomes longer. By morning, the fourth or fifth cycle that ends when one arises for the day could allow for 45 -60 minutes of uninterrupted REM sleep.
The Sequence of Sleep Stages
Sleep does not sequentially pass through all these stages. Sleep begins in stage 1 and advances to 2, 3 and 4. From stage 4, stage 3 and 2 is repeated before advancing to the REM slumber. Once done with REM sleep, usually the body goes back to the second stage of sleep. Sleep goes through these stages for about four or five times per night.
How Much Sleep does the Average Person require?
Sleep cycles targeted dictate the amount of sleep one requires. For example, assuming each cycle lasts 90 minutes then a 7-hour sleep wakes one in the middle of fifth cycle of sleep. This avoids the fifth REM sleep. Researchers advise that it is healthier waking up during the light stage 1 after completion of a cycle. One waking up during REM sleep is susceptible to grogginess capable of lasting the entire morning or all through the day. Ever wondered why you sleep for eight hours and feel like you never had some rest?
For most people especially students it is advisable to wake up between 5a.m and 7a.m. Research reveals that this is the time the body cleans its digestive system, removing waste and toxic products from the system. Health specialists recommend light and healthy drinks after waking up to aid the process of digestion. Breakfast is taken on time to prevent the body from assuming state of survival for delayed meals making one feel no urge to eat despite spending several hours sleeping.
A 20 to 30 minute nap is advisable after having lunch especially for students to help reorganize the brain. The brain becomes fully active at around 3pm to 5pm, about 8 hours after waking up, and has high chances of remembering what is taught. For recreational purposes for couples, the period advised is 9pm to 11pm since there are high chances of conception.
In conclusion, it is evident from scientists that various cycles characterize the night sleep. The stages sums to five in one sleep session. The first, second, third, fourth and fifth stages of sleep constitute this. Each stage has its characteristics and metabolic activities associated with it as described above.
Cherry, Kendra. Stages of Sleep. 2012. 03 Feb 2013
Nevid, Jeffrey S. Psychology: Concepts and Applications. New York: Cengage Learning,