The Science of Sleep

It’s obvious that sleep is important. Sleep is a necessary part of life. Without it, both the mind and body gradually begin to shut down. In all honesty, though, have you ever wondered why the human body needs sleep? Or why we feel as equally tired no matter if we are performing either purely physical or primarily mental activities throughout the day? What then, is the purpose behind sleeping? “The great sleep researcher and pioneer Allen Rechtschaffen noted that ‘if sleep does not serve an absolute vital function, then it is the biggest mistake the evolutionary process ever made.’ ” (Assefa, Diaz-Abad, Wickwire, & Scharf, 2015, p. 71).

The ability to sleep serves many purposes. Not only does sleeping provide a way for the body to both rest and recharge itself, but it also serves to improve both biological and psychological functions. According to Kalat (2013), there are three explanations as to why we sleep. The first, and probably the most important, justification is that it helps in energy conservation. During this period, the body adjusts to lower energy expenditures through a variety of physiological processes, such as decreasing metabolism, temperature regulation, motor functioning, and muscle activity. “Sleep conserves energy during the inefficient times, when activity would be wasteful and possibly dangerous” (Kalat, 2013, p. 288).

The second explanation is based on the idea that sleep is essential to the function of memory. Given the impairment that sleep deprivation has on memory, it’s not at all unexpected that sleep is required for many tasks associated to memory. The hippocampus, one of the primary structures of the brain associated with memory, has been found to undergo similar activity during periods of sleep as it does during the active processing of memory (Kalat, 2013). For instance, research has shown that the act of sleeping improves overall memory capabilities in remembering and maintaining new information. According to Rattenborg, Lesku, Martinez-Gonzalez, & Lima (2007), studies on fruit flies placed into a heightened learning environment early in their life cycle required vastly sleep comparatively to the fruit flies in a less stimulating environment. Increased ability to learn has also been noted to follow short periods of rest, including naps. Additionally, the hippocampus, one of the primary structures of the brain associated with memory, has been found to undergo similar activity during periods of sleep as it does during the active processing of memory. Lastly, sleep function to enhance memory capabilities by eliminating incomplete or unnecessary information from the brain, consequently diminishing weak synaptic connectivity during periods of wakefulness (Kalat, 2013).

The final explanation for the function of sleep is that the Rapid Eye Movement (REM) stage of sleep services an organic and biological purpose. REM sleep is characterized by its slow-wave brain pattern, high-amplitude, and its early appearance following sleep (Why Do We Sleep?, 2015). REM is said to be the most important stages of sleep, comparatively to NonRapid Eye Movement (NREM), mainly because humans spend the greatest amount of time while asleep in this stage. The increase in neuron activity occurring during REM sleep is thought to help in sensory or motor circuit development, in addition creating standard patterns in body regulation and. REM sleep is also thought to be imperative to memory formation, as well as decreasing the number of inappropriate connections or content leftover from earlier transmissions of memory (Kalat, 2013).


Assefa, S.Z., Diaz-Abdad, Wickwire, E.M., & Scharf, S.M. (2015). The function of sleep. AIMS Neuroscience, 2(2), 71-90. doi:10.3934/Neuroscience.2015.2.71

Kalat, J.W. (2013). Biological Psychology (11th ed.). London: Hodder.

Rattenborg, N. C., Lesku, J. A., Martinez-Gonzalez, D., & Lima, S. L. (2007). The non-trivial functions of sleep. Sleep Medicine Reviews, 11(5), 405-409. doi:10.1016/j.smrv.2007.04.003

Why do we sleep? (2000). Nature Neuroscience, 3(12), 1225-1225. doi:10.1038/81735

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