Written by Haarika Gogineni and Edited by Kevin Liu
Sleep deprivation is an omnipresent issue that affects every person– from parents of newborns to members of the workforce, and from adolescents in school to celebrities. Many communities around the world claim that lack of sleep has varying effects on the human body such as being an overall detriment to health, having hallucinogenic effects, and even increasing appetite. As such, the effects of sleep, or lack thereof, on cognitive performance and physical and metabolic function have long been debated by the empirical community.
Sleep, which is made up of the five different stages, works to restore and regulate the body. The first four stages are classified as Non-Rapid Eye Movement (N-REM) sleep and are essential for body reparation, generation of new tissue, and release of hormones [1]. In the final stage, Rapid Eye Movement (REM) sleep, the brain is active in dreaming and stimulates brain regions involved in learning [2]. The human body cycles through these five stages of sleep multiple times throughout the night and thus rejuvenates our body for the next day.
Sleep quality and length needs are determined mainly by genetics and age — factors that impact an individual’s preference for being an “early bird” or a “night owl” [3]. Although the exact number of hours a person needs to sleep varies from person to person, adults generally require 7.5-8.5 hours of sleep to function optimally. Yet, many individuals do not receive the required amount of sleep, resulting in widespread sleep deprivation [6].
Common groups that demonstrate lack of sleep include college students, adolescents, working individuals, and parents. Though this may potentially be due to work, financial stress, and emotional or mental health concerns, a great majority of sleeplessness also results from bad sleep hygiene. Sleep hygiene — defined as sleeping habits such as bedtime, duration, and setting — all contribute to the quality of sleep. As a result, bad sleep hygiene compromises the quality of sleep that an individual gets. An accumulation of environmental stressors and bad sleep hygiene leads to major sleep loss and negatively affects an individual’s health and ability to function normally.
A study which compared students’ academic performance on mid-term examinations and quizzes to their sleep quality determined that college students showed better performance with longer sleep duration and better sleep quality [5]. The strong correlation between performance and sleep is due to the physiological responses of sleep deprivation. Based on brain imaging studies, scientists found that a lack of sleep is associated with activity in the prefrontal cortex that negatively impacts an individual’s decision-making and complex thought processing ability [6]. Other studies relate sleep to memory in that sleep is a physical state in which the brain optimally functions to consolidate memories. Slow-wave sleep, the deepest phase of the N-REM sleep, is especially crucial for memory consolidation since recent memory representations are transformed into long term memories during this phase [7]. As a result, reduced sleep hygiene results in poorer memory retention and recall.
In terms of the physiological effects of sleep, there seems to be a similar correlation between both physical and metabolic function, and sleep hygiene. During sleep, the body fully relaxes and releases hormones and chemicals essential for restoration and rejuvenation of the body. As a result, many athletes are encouraged to get a full night of rest in preparation for competitions or for recovery. This is important because overexertion in a physical capacity reduces one’s ability to heal and to adhere to proper sleep hygiene [8]. Moreover, lack of sleep reduces the effectiveness of metabolic function and results in a higher risk of obesity [9].
In essence, sleep deprivation is a widespread phenomenon that detrimentally affects cognitive performance and physiological and metabolic functions. The only way to truly solve this ongoing problem is to encourage healthy sleeping habits by promoting self-care and good sleep hygiene. Even taking small steps, such as setting a bedtime or turning off electronic devices, could substantially improve sleep and general health.
References:
1. Bouthier, Bente. (2018). Sleep in Different Cultures. Moment of Science.
2. Unknown. (2019). What Happens When You Sleep?. National Sleep Foundation.
3. Unknown. (2008). Assess Your Sleep Needs. Healthy Sleep Harvard Medicine.
4. Davis, Kathleen. (2018). What to know about sleep deprivation. Medical News Today.
6. Killgore, W.D. (2010). Effects of sleep deprivation on cognition. Science Direct. 185:105-29.
7. Rasch, B., Born, J. (2013). About Sleep’s Role in Memory. Physiological Reviews. 93(2): 681–766.