1a- Why do we sleep? Literary Review by Eva Georgiou

In order to innovate, one must fist understand the rules and processes that normally take place. Only then can we break these rules, and develop new ways of achieving than prior. Despite the many technological and scientific advances of the last century, there are many processes that occur within people and the world which science does not fully understand. The bodily process of sleep is one of these.

All processes within the human body are the product of millions of years of evolutions. Through natural selection, favourable traits that optimise chances of survival are passed onto the next generation, via reproduction. The development of sleep follows this same process. However when considering that sleep renders an organism defenceless for a period of time, it begs the question as to why another, more improved version of this function did not develop. Thus, ‘Sleep must confer some essential benefits to outweigh these serious disadvantages.’ (scientific American, 2017)

Human beings spend on average one-third of their lives asleep. So how does this process that we spend so much of our lives doing work? During the day, our brain which acts as a biological clock, is kept awake by various hormones. This is related to cycles of day and night within our environment of the individual. These cycles within organisms are called circadian rhythms. Melatonin is then released to prime the body for sleep by inducing fatigue. From this, it can be gathered that in a controlled environment, sleep is biologically influenced by light in our environment.

It is still not clear exactly why organisms sleep, but it is apparent that it is vital for life. A study was conducted, ‘on rats, showing that those deprived of sleep died sooner than those who were deprived of food.’(Tu-Anh Vu 2017) Based on this evidence, it can be deduced that sleep is more of a necessity for life than food for an organism.

So what is our body doing during sleep that is so vital for survival? Prior theories revolved around sleep being used by the body to repair cells that are damaged during waking hours, however this process also occurs while awake. More recent neuroscience studies have found evidence that suggests that sleep is actually used to process information intake from throughout the day, and consolidating memories. As stated in the episodes of Insight specifically related to sleep, The first few cycles of sleep are mostly maintenance work. The last cycle you get into filing, filing information you have collected throughout the day and gather it. (Insight 2016) This is also supported by the lecture K. Tanga 2017, lecture, which stated one of the negative impacts of sleep deprivation is a 40% reduction in memory formation.

Sleep is the only time where the prefrontal cortex of the brain can rest, and consolidate this information intake from the day, throwing out unnecessary content and storing those that are important as memories. This was tested through an experiment using sleep deprivation and then testing its effect on memory. The experiment used, ‘cleverly designed sleep deprivation experiments, the two papers in this issue extend this result by demonstrating an absolute requirement for sleep within 30 hours of training. Importantly, it was the occurrence of sleep and not the simple passage of time that was critical.’ (why do we sleep 2000).

Through this general understanding of why we sleep, how these bodily processes take place and why it is vital for our existence, more innovative technologies can be developed from this grounded understanding. This evidence also changes the way in which we understand sleep and its function in organisms, allowing for more targeted, personal and effective treatments for sleep deprivation in people.

 

REFERENCES:

Scientific American. 2017, Why did sleep evolve?, viewed 18 August 2018, < https://www.scientificamerican.com/article/why-did-sleep-evolve/>.

YouTube 2017, Why Do We Have To Sleep?, videorecording, YouTube, viewed 18 August September 2017, <https://www.youtube.com/watch?v=3mufsteNrTI&gt;.

Tu-Anh Vu . (2017). The Evolutionary Basis of Sleep | Serendip Studio, viewed 18 August 2017, <http://serendip.brynmawr.edu/exchange/tu-anh-vu/evolutionary-basis-sleep&gt;.

‘why do we sleep?’ 2000, Nature Neuroscience  vol. 3, no.12, p. 1225.