Sleep is a universal concept that incorporates animals and humans alike. The melatonin released from their brains allow their bodies to experience a periodic unconsciousness that re-energizes and regenerates their beings to allow for basic survival. This loss of consciousness enables the brain to maintain functionality and to process the information without continuous awareness and effort.
Stages of Sleep
NREM-1 sleep, known for being a brief stage in the sleep cycle, is the first stage of sleep when the brain slips into a hypnagogic state. Hypnagogic is the term that refers to the brief moment between consciousness and unconsciousness. During this fleeting moment in time, the body starts to take deeper, slower breaths and creates irregular brain waves which is more commonly referred to as alpha waves. While the muscles in the body relax, it is normal for the brain to create hallucinations that mimic sensations when the body itself is not experiencing the stimulus. For example, the brain may create this hallucination that the body is falling through the sky; the body, in turn, will react to the stimulus by jerking instantaneously. The brain creates fleeting images so that if the body were to wake during this stage, it would only remember fragments of a dream.
NREM-2 sleep is the second stage of the sleep cycle that lasts on average of twenty minutes. At this point, the body is becoming more relaxed. In contrast, the brain starts creating activity of random, rapid bursts of rhythmic brain-waves which are also known as sleep spindles. While the body can wake easily during this stage, the body is showing the typical signs of unconsciousness. Most of the entirety of sleep each night is spent during this stage.
NREM-3 sleep is the third stage of the sleep cycle that lasts on average of thirty minutes. After the rapid bursts of brain activity, the brain starts to slow down by creating slow, large brain waves which is also known as delta waves. The body becomes fully relaxed by the end of this sleep cycle, which is why it is common for children to wet the bed at this stage of sleep. If the body were to wake during this stage, there would be little to no cognitive awareness.
REM sleep, also known as rapid eye movement sleep, is the final stage of the sleep cycle. Commonly referred to as the paradoxical sleep, this is the sleep stage when the brain is fully active while the body is externally completely still, almost to the point of being paralyzed. Internally, the organs of the body are fully at work: the heart is creating a higher heart rate, the lungs are creating irregular and rapid breaths, and the eyes are periodically creating rapid bursts of energy to dart across behind its eyelids. Fully characterized by this factor, the rapid eye movement is an indicator of both the commencement of this sleep cycle but also the start of a dream. In the brain, the brain waves are akin to NREM-1 brain waves where the waves are rapid and irregular. Even though the brain and other organs in the body are hard at work, the brain blocks messages from the motor cortex to reach the brain stem; therefore, the body cannot fully respond to stimulus that the brain is creating in the dreams/hallucinations like in the NREM-1 stage. If the body were to wake during this sleep stage, the brain would remember the majority of the dream that was just created in a story-like format.
This cycle repeats every ninety minutes; but as the cycle persists, the NREM-3 stage becomes more and more insignificant to the point where it disappears. While the overall sleep cycle is getting less of NREM-3 as the body sleeps, the NREM-2 and the REM stage grows more periodically. Even though the sleep stages are described as a cycle, the stages do not progress in a cyclical motion but rather a wave. The body falls into NREM-1, into NREM-2, into NREM-3, but before the body can fall into REM sleep, the brain must go back to NREM-2. In the overall sleep cycle, NREM-1 is experienced for two percent of a typical night’s sleep while REM is experienced for twenty to twenty-five percent of a typical night’s sleep.
The magic number of optimal hours of sleep does not exist, but lies within the context of the age of the person. Infants sleep on average about sixteen hours a day, while adults can function by sleeping within a range of six hours to nine hours a day. The amount of sleep a person needs is dependant on themselves. Some people’s daily life requires a midday nap that can range from fifteen minutes to ninety minutes. Some people find that they are awake midway through the night and have two seperate sleep cycles. These sleep patterns are influenced genetically and cannot be defined into a formulated answer.
Benefits of Optimal Sleep
Sleep is the period of time that the body uses to create new cells to repair and renew itself and its immune system. During sleep, the body releases growth hormones from the pituitary gland, which promotes muscle growth. As the body’s muscles grow, the more energy it is allowed to exert during the day. While the body has time to rejuvenate, the brain takes this time to reinstate information or memories from the previous day. The information that was just learned is reactivated during sleep, and in turn creates stronger neural connections. This is why study tips mention that students should study their notes right before they go to bed; rather than sleeping on the notebook hoping for osmosis to occur, the brain actually reinforces the information and carries it from the hippocampus into permanent storage in the cortex.
Disadvantages of Insufficient Sleep
Due to lack of sleep, the body is unable to create those lasting neural connections or repair cells in the body, as stated above, but the body also starts to gain a sleep debt after a series of insufficient sleep hours. Even if the body receives one hour less than the recommended amount, the body starts to accrue this debt after so many nights of inadequate sleep that cannot be repaid by sleeping for a whole day. The body’s functionality starts to shut down, making it difficult to retain attention or carry out tasks to its fullest potential. Sleep deprivation can lead to weight gain due to its increase of ghrelin (a hunger-inducing hormone) and cortisol (a stress hormone that trigger the body to produce fat) and its decrease of the body’s metabolic rate.
Sleep Journal Data
Sleep Journal Data (Continued)
Sleep Journal Data (Continued)
Sleep Journal Review
Based off of the information acquired from the sleep journal, my sleep schedule fluctuated based on my activity the following day. The nights before Tuesday and Thursday— where my days start roughly around 7:30 a.m.— I would receive an average of five hours of sleep. The amount of times I pressed snooze on Tuesdays and Thursdays ranged from five times to “continuously for an hour”. However, on the nights before Monday, Wednesday, and Friday— where my days start roughly around 12:00 p.m.— I would receive an average of eight hours of sleep. On the nights I would receive five hours of sleep, I would have been woken up by my alarm clock after three full cycles of sleep and in the midst of the NREM-2 sleep stage. On the nights I would receive eight hours of sleep, I would have woken up after five full sleep cycles.
As expressed through the “Number of Times Snoozed” factor, I was groggy on my earlier mornings due to my late nights. While most of those late nights were spent doing homework, some were spent doing nothing but looking at a screen. The variable of time that is expressed by the “Time in Bed” factor and the “Time Fell Asleep” factor is the amount of time spent awake in bed, predominantly going through social media. The blue light of a cell phone screen decreases the level of melatonin produced by the suprachiasmatic nucleus, allowing me less sleep and therefore making me groggy in the morning.