Why do we sleep?

As we spend approximately a third of our lives sleeping, it comes to no surprise that sleep plays a vital role and is considered to be a fundamental pillar for our health and well-being.

Although the exact function of sleep is yet to be fully understood, sleep deprivation studies have revealed numerous consequences of inadequate sleep. Each of these will be further detailed in upcoming sections. To name a few, lack of sleep has been shown to impact:

• Cognitive performance;
• Memory and learning;
• Neuronal connections and maintenance;
• Emotional regulation;
• Appetite regulation and insulin resistance;
• Cellular repair and development;
• Inflammation and immune response;
• Etc.

On the more extreme scale, animal studies have shown that continuous wakefulness can result in cognitive breakdown, organ failure and even death. Luckily, such situations, where no sleep is obtained over multiple days, is a rare event in normal human life.

Nevertheless, sleep deprivation is a common occurrence in our population. In 2018, the National Sleep Foundation reported that approximately 65% of adults are sleeping less than 7 hours a night during weekdays. Consequential effects of sleep deprivation are cumulative over time and, therefore, may be a contributing factor to standard western health disease and psychological troubles such as hypertension, diabetes, obesity, depression, and dementia.

Therefore, although the exact functions of sleep remains to be identified, we know that placing focus on  a good night’s sleep will have significant benefits for our health, our performance, and well-being.  

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Selected Supporting References

• Thomas, M., Sing, H., Belenky, G., Holcomb, H., Mayberg, H., Dannals, R., et al. (2000). Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. Journal of Sleep Research, 9(4), 335-352.
• Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272-1278.
• Vandekerckhove, M., & Cluydts, R. (2010). The emotional brain and sleep: An intimate relationship. Sleep Medicine Reviews, 14(4), 219-226.
• Van Cauter, E., Spiegel, K., Tasali, E., & Leproult, R. (2008). Metabolic consequences of sleep and sleep loss. Sleep medicine, 9, S23-S28.
• Bryant, P. A., Trinder, J., & Curtis, N. (2004). Sick and tired: does sleep have a vital role in the immune system?. Nature Reviews Immunology, 4(6), 457-467.
• National Sleep Foundation, Quarterly Sleep Health Index (2018 – Q1). Accessed at: https://www.sleepfoundation.org/sites/default/files/inline-files/SHI%202018%20Q1%20Report_final2.pdf
• Everson, C. A., Bergmann, B. M., & Rechtschaffen, A. (1989). Sleep deprivation in the rat: III. Total sleep deprivation. Sleep, 12(1), 13-21.