Loss of sleep

Sleep deprivation is an escalating, global health problem. Individuals, of all ages, are experiencing the detrimental effects of sleep loss—whether heredity or by other explanations. Evidence has displayed both acute and chronic effects on health—disruption in behavior, mood, and immune system, as well as, susceptibility to obesity and illnesses. Briefly, perception and physical responses are weakened; mood is transitioned from normalcy to heightened sensitivity and depression. These emotional depletions have the likelihood for accidents and poor performance. Similarly, internal imbalances disrupt the proliferation and engagement of T cells, who defend the body from invaders; internal hormones fluctuate with reduced sleep—seen with leptin and ghrelin, facilitating body mass index (BMI). Studies suggest chronic illnesses such as respiratory and cardiovascular diseases are elevated with sleep loss and early diagnosis may prevent such outcomes. With much evidence displaying negative results of sleep loss, researchers hope action will be taken to improve health.

Sleep is a necessity, a vital piece of survival. As stated by McKnight-Eily et al., in Relationships between hours of sleep and health-risk behaviors in US adolescent students, “The tolerated minimum sleep time is approximately 6 hours….” (95). However, each year, people are progressively receiving a shortened supply, which has concerning effects on performance and body. Sleep deprivation, as defined by its name, is receiving an inadequate amount of sleep. This can be complete or partial sleep loss. The cause of this anomaly can range from genes to intentionally losing sleep for prioritized matters—the latter predominate over the former. Studies have shown that this condition has escalated dramatically over the years, exclusively in adolescents—who are more vulnerable. These individuals, among others, are aggravated by social, academic, and biological changes, and must adjust to them. With excessive time spent on technology, academics, work, and other contemporary lifestyle choices, allocating time for sleep becomes secondary. “Insufficient sleep on an average school night was reported by 68.9% of students” (McKnight-Eily et al. 271). It is abundantly clear that sleep deprivation in students, among others, has increased at a global level. This behavior, for whatever cause, has detrimental acute and chronic side effects that must be examined, as it concerns majority of the population. I will attempt to list a few major effects of sleep loss on performance, mood, health, and potential long-term risk related issues.

Performance and Mood

For better comprehension, performance will be analyzed first, as it concerns the over-all behavior of the individual. Globally accepted, sleep deprivation has concerning effects on mood and performance. A person’s ability to perceive and comprehend their surrounding is weakened, which can lead to adverse outcomes. Kathleen Davis highlights in her article, “What’s to know about sleep deprivation?” lack of sleep has detrimental side effects, such as, its competence to alter “normal functioning of attention and disrupts the ability to focus on environmental sensory input.” This disruption can potentially cause accidents—whether in automobiles, trains, ships, or airplanes. Not only that, in “Consequences of Sleep Deprivation,” by Jolanta Orzel-Gryglewska, “Sleeplessness accounts for impaired perception, difficulties in keeping concentration, vision disturbances, slower reactions, as well as the appearance of micro-episodes of sleep during wakefulness which lead to lower capabilities and efficiency of task performance and to increased number of errors. Sleep deprivation results in poor memorizing, schematic thinking, which yields wrong decisions, and emotional disturbances such as deteriorated interpersonal responses and increased aggressiveness” (95). Clearly, perception, behavior, and memory are highly disturbed without sleep; it has ominous consequences on performance and can negatively affect day-to-day behavior.

Similarly, in “Relationships between hours of sleep and health-risk behaviors in US adolescent students,” by McKnight-Eily et al., the authors emphasize the amount of sleep, or lack of, can correlate to health-risk behaviors. In 2007, the authors conducted research by taking the self-reported Youth Risk Behavior Survey (YRBS) on 12,154 US students. These individuals had cataloged the amount of sleep they received each school night, whether < 8 (inadequate sleep) or ≥ 8 (adequate sleep). Results showed that two-thirds of the student population was receiving insufficient sleep (McKnight-Eily et al. 271). McKnight-Eily et al. argue that high school students, who suffer from sleep reduction, are more prone to health-risk behaviors. This includes the intake of cigarettes, marijuana, alcohol, and carbonated beverages (271). These individuals are more inclined and susceptible to peer-pressure by participating in sexual activity, physical fighting, suicidal thoughts and attempts, and computer usage. Thus, it suggests that sleep loss has a prominent role in ill-advised behavior.

Moreover, the authors had examined any major correlation between age, sex, and ethnicity with sleep deprivation. The results showed that about half the participants were female—who reacted equally to shortened sleep as males do, except in one case, where men watched more television than females. Additionally, ethnicity played an important role. Students who were African American or Hispanic had a greater tendency to be physically less active when sleep deprived compared to Caucasian students (McKnight-Eily et al. 272). However, in “Sleep Deprivation leads to Mood Deficits in Healthy Adolescents,” Michelle A. Short and Mia Louca, who had conducted research by abstaining 36 hours of sleep from students, had contradicting results from McKnight-Eily et al. findings. “Females showed a greater vulnerability to mood deficits following sleep loss, with greater depressed mood and anxiety following sleep deprivation only witnessed among female participants. While both males and females reported more confusion following sleep deprivation, the magnitude of this effect was greater for females” (Short and Louca 987). They noticed that females reacted more severely to sleep deprivation at an emotional level, with a greater vulnerability and sensitivity compared to male participants. Short and Louca had analyzed “the discrete mood states of anger, depression, anxiety, confusion, fatigue, and vigour in healthy adolescents” (987). It was seen that viguor decreased and fatigue increased. A few experiments even showed that emotional responses such as anxiety, depression, sadness, and anger had increased. On the other hand, these negative mood responses hadn’t shown to escalate, or better, over time, “while vigour, confusion, and fatigue worsen with moderate levels of sleep restriction, mood states” (987). This may propose that with progressive sleep loss, the emotional response, typically negative, will remain consistent.

It is important to note that both articles by Mcknight-Eily et al. and Short and Louca were on “adolescents”—because their “…brain maturation, sleep homeostatic and circadian system function, and psychosocial milieu.…” is different from adults (Short and Louca 988). It is also important to note that McKnight-Eily et al. had conducted most of their research on the “physical” response to sleep deprivation, while Short and Louca examined primarily the “emotional” response. Additionally, both experiments had the participants write in their responses; however, the environment in which it was done was different. In Knight-Eily et al., the participants reported from an accustomed surrounding, whether their homes or school, while in Short and Louca’s experiment, participants were accommodated into a laboratory for a few days—where there was a lack of carbonated beverages, computer systems, coffee, etc. (items available at home that may sever the response to sleep loss) that could possibly have heightened results. By comparing both articles, it can be said that both sexes react relatively the same physically when sleep deprived; however, at an emotional level, women are affected more severely. Nevertheless, lack of sleep has impactful consequences on behavior and mood.

Immune System

Furthermore, sleep deprivation has severe consequences on health—specifically, our immune system, which is responsible for removing any harmful or toxic substances and/or organisms from within the body. It plays a crucial role in keeping the body healthy and balanced. The immune system contains many participants that allow it to function efficiently and consistently; however, for clarity, a few key players will be examined profoundly, specifically, T cells—a form of white blood cells that circulate within the body, searching for intracellular infection or any abnormalities that must be eradicated. T cells are produced, just as B cells, in the bone marrow. When T cells reach maturity, they move to the thymus gland. They include “helper T cells” and “killer T cells” among others. Each of these T cells play an important role in activating certain signals and behaviors, such as, cytokines.

In “What are Cytokines?” Dr. Ananya Mandal defines, “…cytokine is derived from a combination of two Greek words – ‘cyto’ meaning cell and ‘kinos’ meaning movement. Cytokines are cell signaling molecules that aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.” Cytokines allow for communication and synergy among antigen presenting cells and T helper cells of the adaptive immune system. Equally important, Basedovsky et al., concede in Pflügers Archiv, that sleep expedites the production and discharge of T cells. T cell production is active during sleep, as the circadian rhythm or internal body clock, plays a significant role in regulating and influencing many bodily functions—one of which includes, production of T cells; T helper cells release cytokines to protect the body from any harm, as mentioned earlier. In contrast, lack of sleep may ensue stress. This activates the hypothalamus (homeostasis regulator) that releases the hormone ACTH (Adrenocorticotropic), which in turn, discharges Cortisol (a stress hormone), suppressing the production of cytokines. This weakens the immune system, decreasing cytokine signaling, and, ultimately, increasing susceptible to diseases and chronic illness.

Adding on, pro-inflammatory cytokines include IL-21, TNF-α, IL-1, IFN-γ and PCR. Interleukin 1L-1β (vital intermediary of the inflammatory response) may act as both a pyrogen (fever producing) and a somnogen (sleep producing)—this would further demonstrate the prolonged sleep period required for recovery during sickness (Orzel-Gryglewska 102). It also links to sleep debt, as sleep reduction increases, more sleep is needed to balance out.

Likewise, TNF-α (tumor necrosis factor alpha) is an inflammatory cytokine as well. Type 1 is affected by sleep reduction. However, studies based on TNF-α and sleep reduction have shown oscillating results. Some have seen both elevation and depletion in TNF-α and/or its complementary receptors. But it is worth noting, in “Cardiovascular, Inflammatory, and Metabolic Consequences of Sleep Deprivation,” emphasized by Mullington et al., that “… incompletely understood individual differences in vulnerability to sleep loss may underlie these discrepancies, or perhaps subtle but important differences in methods” (298). Given these points, more experimentation is needed to eliminate cofounding factors, as results are too skewed.

Long-term effect: Obesity

Granted, lack of sleep, weakens the immune system, making susceptibility to infections and illnesses higher. So far, only acute effects have been listed, such as behavior and mood. Now, potential long-term (chronic) effects will be mentioned, such as, major depression, obesity, diabetes, respiratory and cardiovascular diseases. It is important to recognize that the corollary of many mental disorders is major depression (McKnight-Eily et al. 271). Here, the authors establish that shortened sleep can affect not only the body but the mind as well. Not only that, but Mullington et al. in Progress in Cardiovascular Diseases, suggest “Fewer people are aware that chronic sleep complaints in epidemiologic studies have also been associated with an increase in overall mortality and morbidity” (294). It is apparent: not receiving sufficient sleep can facilitate illness, mental disorders, and mortality. Since there are numerous studies done on chronic sleep deprivation on multiple illnesses and long-term health-risks, we will examine obesity in depth, solely, because it is a prevalent (growing) issue among Americans.

Taheri et al. in “Short Sleep Duration is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index,” disclose their conducted research on 1,024 participants from Wisconsin Sleep Cohort Study. The volunteers participated in a longitudinal cohort study, where they were analyzed for 15 years. “Participants underwent nocturnal polysomnography and reported on their sleep habits through questionnaires and sleep diaries.” Notedly, these are self-reported data from volunteers, which potentially could have led to miscalculations. Blood samples were analyzed to witness any fluctuation or escalation in hormones—insulin, adiponectin, ghrelin, leptin, lipid profile, and glucose. The two key hormones leptin and ghrelin play critical roles in the increase and decrease of body mass index (BMI). Leptin plays a role in “long term regulation of energy balance,” whereas Ghrelin plays a role in “meal initiation” (Klok et al. 21). Upon research, “In persons sleeping less than 8 h (74.4% of the sample), increased BMI was proportional to decreased sleep. Short sleep was associated with low leptin…with a predicted 15.5% lower leptin for habitual sleep of 5 h versus 8 h, and high ghrelin….” (Taheri et al.). This suggests that when sleep is deprived, there is greater BMI; leptin levels decrease, so energy in fats is less regulated, while ghrelin levels increase, appetite increases, thus, BMI increases. Those awake at night for long periods tend to crave high calorie foods that are rich in lipids, which allow quick expenditure of energy. There is a “deregulation of leptin-ghrelin system….” (Tobaldini et al. 321). However, Taheri et al., emphasize that there were discrepancies, predominantly, in assaying ghrelin samples from all participants, as there was not enough serum available to manage this. Similarly, Knutson et al., suggest there is a three-way correlation between sleep deprivation, weight gain, and diabetes: “(1) alterations in glucose metabolism; (2) upregulation of appetite; and (3) decreased energy expenditure” (163). Sequential correlation between increased sleep loss, low energy expenditure and upregulation of appetite, results in weight gain. Moreover, it may heighten the likelihood of diabetes. Although the authors conclude there is a pathway, they still want to emphasize that most of these studies are “self-reported measures” and can’t be measured for accuracy. Once again, confounding factors and methods may have altered results.

Conclusion

In brief, with loss of sleep comes many detrimental side effects—acute and chronic. Behavior, mood, internal body systems, susceptibility to illness, and obesity are all altered due to this disruption—emphasizing the importance of maintaining a healthy lifestyle, especially sleep, whose primary job is to recover the body from daily activities and bring back homeostatic physique. Lack of sleep alters mood from normalcy to sensitive and depressed. Likewise, it weakens attention, resulting in accidents. Internal systems are disturbed as well; cytokines less active to engage invaders; leptin and ghrelin hormones (among others) unbalanced/deterred. It is evidently clear, sleep plays a crucial role in our over-all wellbeing. Moreover, it is important to comprehend these negative effects, as it effects all age groups—prominently, adolescents, as it is a critical period in their life, where habits may form. On a larger scale, it is important to be aware, so policy decisions and public health may resolve and promote sleep’s importance and diagnose early to find any abnormalities or illness before it progresses. Lastly, with all the data obtained, there is still some discrepancies and gaps that must be better understood and examined, discounting confounding factors—for instance, age, sex, ethnicity, illness, and hereditary—that may result different physiological responses.