It is recommended to have at least eight hours of sleep every day. This is especially recommended for today’s adult professional. Now, some people are lucky enough to get the full eight hours recommended. Others, unfortunately, get just about four to six hours of sleep each day. Regardless, they are still able to function well enough. Or so they claim.
But regardless of how many hours of sleep you get, do you really know why you sleep? Just why do we sleep? The seemingly easy way to answer this question is to liken the activity of sleep to eating. You eat to sustain your life – that is a fact. In this sense, hunger becomes a protective mechanism, something that we go through to make sure that we eat and consume all of the nutrients that our bodies need to function efficiently. The body needs food and nutrients to grow and to repair tissues so we consume food to do exactly this. Going without food is detrimental to our health and ultimately makes us feel hungry. When you go without sleep, it makes us feel sleepy as well. So in this sense, eating and sleeping are alike. Still, it does not answer the logic behind sleeping – the need to sleep itself.
Why do we really sleep? There have been several theories and angles explored by scientists and researchers. Sleep patterns, sleep deprivation, sleep cycles, all these and more have been studied profusely. And as a result, several theories have been reached.
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First, there’s the Inactivity Theory. Another name for this theory is the Evolutionary Theory or the Adapative Theory. This theory suggests that the inactivity at nighttime is ultimately an adaptation taken on by the early organisms. The main reason behind organisms adapting inactivity at nightfall is survival. By being inactive, or by sleeping, organisms survive better because they are out of danger. By survival of the fittest, this evolutionary inactivity was passed on to the organisms of today, including the present human species, and is now globally recognized as sleep.
Another theory is about Energy Conservation. This theory mainly suggests that the purpose of sleep is the reduction of the demand for energy during day or night. Mainly with animals like cats whose are sleep too much, and not human beings, this theory better works at night because this is when it becomes more difficult to hunt for food. Since this is the case, then it is better to conserve one’s energy and just sleep at night.
But one of the compelling theories to date is the Brain Plasticity Theory. This theory suggests that sleep has a correlation with the changes that take place in the organization and the structure of the human brain. Infants, for example, spend approximately 13 to 14 hours in a day just sleeping. Half of the time they sleep, they are actually in the REM (Rapid Eye Movement) stage of sleep – the phase where dreams take place. The theory here is that an infant’s brain hasn’t fully developed yet. Thus, the need to sleep more suggests that sleep is needed for the development of the organization and structure of the brain.
There are still other theories out there. But even if there’s no be-all and end-all theory behind it yet, we do know that we need it to sleep for some great reason.
How Good Sleep Affects Memory and Learning
The human body has the inevitable need to sleep. It is even recommended for adults to have at least eight hours of sleep every day. In the physical sense, there are several theories behind the need to sleep. Energy conservation is one of the simple theories. Since there’s inactivity at night, then it would be better for you to sleep and conserve your energy.
Another theory is restoration. The tasks and activities one undertakes during the day can be daunting and stressful to any human being. Thus, sleeping at night gives your body the chance to restore itself, to recuperate and refurbish torn tissues, regenerate cells in number, etc.
Leaving the physical aspect behind begs the question: Does sleep affect one’s cognitive skills? At a glance, cognitive studies strongly suggest that sleep has a very important function in a person’s memory. And this role that sleep plays actually takes place before learning a new task and after learning such new task.
To understand this better, let us discuss some processes. There are actually two ways that sleep can help both memory and learning. First, if you are deprived of enough sleep, then you cannot focus your attention in the most optimal way. Because of this, you cannot learn a new task as fast and as efficiently as how you would, had you the full eight hours of sleep recommended the night before. Second, sleep helps the brain consolidate memories of the new task learned. It is through this consolidation that the skills learned via the new task are inculcated and assimilate fully and thoroughly. Thus, learning the new task becomes more easier when you have enough sleep.
Though, at present, the mechanisms behind how sleep affects memory and learning are not entirely known, there are three functions that describe the process of learning and memory. Acquisition is the introduction of the new task or new information into the brain. Acquisition is ultimately the first step towards learning a new task. Consolidation comes next, and is the set of processes that stabilizes a memory. Through repeated performance of and exposure to the new task, everything you’ve learned is consolidated into a stable memory. Lastly, recall is your ability to access the memory of the learned task or any piece of information about the learned task after consolidation. This ability to recall the memory or piece of information about the task you learned can be either conscious or unconscious. Whether this is done consciously or unconsciously, you should still be able to recall it.
Now, these three processes are needed for your memory to function efficiently. Both acquisition and recall happen only when you are wide awake. So for these processes, you are physically awake and aware that you are dealing with the learned task. However, with the consolidation of memories, studies show that this process actually take place during sleep. The neural connections responsible for forming memories are strengthened during sleep. Furthermore, studies also strongly suggest that the characteristics of brainwaves that appear during the different phases of sleep are correlated with the brain’s memory functions. Simply put, during REM sleep, procedural memory is consolidated. During slow-wave-sleep, on the other hand, visual learning is processed.
These results strongly indicate that sleep does affect one’s memory and learning capabilities. With this, plus the physical risks that come with sleep deprivation, getting enough sleep is certainly a must for all of us.