Impact Of Sleep Deprivation On The Body: A Literature Review Essay.

Methodology

Question:

Discuss about the Critical Thinking and Research Methodology.
 

Sleep deprivation is the problem of not getting enough sleep or restful sleep, which has adverse consequences for the brain as well as many body systems. The problem of sleep deprivation is associated with symptoms like drowsiness, brief episode of sleep followed by awakening, mood changes and difficulty in concentrating. It is also known as circardian disruption and chronic circardian disruption is associated with increased obesity, mood disorder, metabolic dysregulation and many other heath issues (McEwen & Karatsoreos 2015, pp. 1-10). Hence, Sleep deprivation is a serious problem as it affects overall health of an individual.  As sleep deprivation is associated with impaired alertness and psychomotor performance, it impairs people’s decision making capability (Howard et al. 2014, pp.1-8). For instance, del Angel et al. (2015, pp.68-74) has showed that sleep deprivation impairs performance of many task, hence basic cognitive process of affected individual is hampered. People who do not get enough sleep are also at risk of chronic disease like depression, heart disease, obesity and diabetes. Nedeltcheva & Scheer (2014, p. 293) supported the fact that short and poor sleep quality is highly associated with prevalence of diabetes, obesity and cardiovascular disease.

All the above evidences reflect the fact that sleep deprivation adversely affect human body systems. As the problem of sleep deprivation is increasing gradually, there is a need to be aware about the potential effect of sleep deprivation on the body. This will help to identify specific strategies needed to prevent risk of health issues for affected individual. Hence, the main purpose of this literature review is to explore different impact of sleep deprivation on the body and critically evaluate peer reviewed journal articles on the topic. 

The main research question for the literature review is ‘How sleep different can have impact on the body of affected person?’. With this research question, the main objectives of the literature review are:

• To find out different impact of sleep deprivation on body
• To evaluate how sleep deprivation affects vital functions of the body
• To evaluate impact of sleep deprivation on overall health and well being

To critically review research article related to the research questions, databases like CINAHL, MedLine, Google Scholar, Cochrane library and PsycINFO will be searched. Key search terms used for the literature review includes ‘sleep deprivation in adults’, ‘impact of sleep deprivation’ and ‘sleep deprivation and impact on the body’. The inclusion criteria for selecting the articles included:

• The articles must be published in English language
• The articles must be published with 2010 to 2018
• All participants in the study must have problem of sleep deprivation
• Studies with sleep loss and sleep disorder will be considered for literature review

In addition, articles which will be talking about other health issues and not sleep deprivation will not be considered for this literature review. 

Literature Review

Sleep loss and sleep disorder is the most readily treatable health problem yet most frequently overlooked problem too.  Many people fail to realize sleep deprivation as a major health problem and do not seek treatment for it. As sleep deprivation hinders daily functioning and adversely affects health and longevity, not taking treatment at the right time may inhibit the possibility of preventing serious public health consequence. Hence, this literature review is important to raise awareness about the deleterious health impact of sleep loss. The following are the key insights that have emerged from the review of relevant articles for the topic:

The research by Arble et al. (2015) presented the impact of sleep disruption and sleep disruption on metabolic function of the body. It showed that circardian disruption is independent risk factors for insulin resistance and hyperglycemia. The researcher mainly conducted workshop based study by bringing experts in sleep and circardian research together to understand current knowledge related to impact of sleep deprivation on metabolic control. The main discussion from the workshop was summarized in the research article. One of the findings of the study was that short sleeps increased risk of diabetes as sleep restriction affected molecular mechanism in peripheral tissues and resulted in alterations to insulin sensitivity within adipocytes. This ultimately had effect on energy metabolism. High risk of diabetes was also found in affected people because carcardian disturbance has impact on glucose metabolism. The strength of the study was that causal relationship between sleep disturbance and metabolic risk was effectively explained by researchers. The result is also found consistent with other studies as Kim, Jeong & Hong (2015) also gave evidence regarding impact of sleep disturbance on metabolism and insulin sensitivity. Furthermore, Arble et al. (2015) was also successful in giving directions for future research. For instance, it showed that it is necessary to focus on molecular mechanism linking insufficient sleep and circardian dysfunction as it has not been explored in past research.

Arble et al. (2015, pp. 1849-1860) gave indication of risk of diabetes by linking short sleeps to alteration in insulin sensitivity. Vetter et al. (2015, pp.1707-1713) gave new insight to explain about the risk of diabetes due to sleep loss. Arble et al. (2015, pp. 1849-1860) work mainly associated type 2 diabetes risk with short and long sleep durations, however Vetter et al. (2015, pp.1707-1713) mainly opined that in addition to sleep duration and frequency, sleep timing may also influence metabolic processes. The work schedule of a person is one factor that can affect circardian clock. Hence, the study mainly aimed to examine mismatch between sleep timing and work schedule and its link with type 2 diabetes risk by observing 64, 615 registered nurses from a Nurse’s Health Study 2 (NHS2). The preferred chronotype of participant was assessed by use of questions on diurnal preference and exposure to night shift was observed in participant since 1989 from the NHS 2 study. The participants were also questioned regarding diagnosis of diabetes. The main insight from the study result was that great interaction was found between chronotype and shift work exposure. For instance, women who had never worked night shift had reduced risk of type 2 diabetes if they had early chronotype characteristics. However, for nurses, who had night shift exposure, late chronotype was associated with high risk of type 2 diabetes. The main significance of the study was that it established chronotype-dependent association to risk of metabolic disease and such large cohort based study studying about circardina misalignment was not done so effectively before. However, this study cannot be totally generalized because late chronotype alone do not determine elevated risk for type 2 diabetes. Unhealthy dietary habits might be responsible for risk of type 2 diabetes too (de Oliveira Otto et al. 2015).

Impact of Sleep Deprivation on Metabolism

Review of literatures has also revealed that sleep deprivation has impact on balance of cortisol, inflammatory markers and cytokine balance. Wright et al. (2015, pp.24-34) focused on investigating the impact of chronic circardian disruption on cortisol and inflammatory proteins on health subjects aged between 20-41 years. The participants were subjected to 3 three weeks normal sleep schedule and then 25 days of sleep deprivation. This experiment proved that circardian misalignment reduces cortisol level and increases stress in sleep deprived person. Hence, the study was successful in explaining the reason for impact of sleep deprivation on cortisol level by explaining about inflammatory imbalances. However, the study also pointed out to the need of assessing pro and anti-inflammatory proteins to make accurate interpretation related imbalance. 

Apart from physiological functions of the body, chronic sleep deprivation is also known to effect cognitive performance and brain function of adults. The study by Almklov et al. (2015, pp. 324-345) aimed to investigate about the effect of total sleep deprivation on brain activation and behavioral performance in younger and older adults. Research in this area was important because there was lack of good studies related to effect of sleep loss on brain function in older adults.  The research was done with patient above 59 years old and that between 18-39 years old and the main focus was to examine the cognitive functions of attention and inhibition in participant. Researchers examined blood oxygen level-dependent (BOLD) activation in participants GO-NOGO cognitive task  after 36 hrs of sleep deprivation. The GO-NOGO task involved sustained attention (GO) and response inhibition (NOGO) in cognitive task. The outcome of the study revealed no difference between in performance on behavioral outcome measures, however neuro-imaging results showed links between sleep deprivation status and age of participants. This link was established after older adults were found to have greater BOLD activation compared to younger participant and they performed effectively in GO-NOGO task. The strength of the study was that the author effectively explained that brain area in the left posterior cingulate remain active during rest state, however its  activity decreases in demanding task where much concentration is required. Hence, the study gave the idea that adults use additional cerebral resources to perform cognitive task effectively and with increases age, older adults have higher brain activation. Despite this result, one factors that limits internal validity of the study is that healthy older adults were taken for the study, hence it affect generalizability of the study. 

Impact of Sleep Deprivation on Cognitive Function

The above two evidences gave the evidence that metabolic functions of the body and brain activation function is affected in people who have sleep deprivation and poor sleep patterns. However, as this literature review is aiming to evaluate different impact of sleep disruption on body system, one research literature also points out to the impact of sleep deprivation on mood of the affected person. Baum et al. (2014, pp.180-190) focused on the issue of sleep disruption mainly in adolescent because they sleep less than eight hours on school nights. The problem worsens not only because of early school start time but also because of late bedtime routine. As there was lack of consistency in past research regarding consequences of short sleep on psychological harm, Baum et al. (2014, pp.180-190) aimed to examine the impact of shortened night sleep on adolescent’s mood and emotional regulation capability. Health adolescents between 14-18 years were included for the study and all had to go through  three week sleep manipulation protocol given and the details of the program is given in Figure 1 below. Sleep monitoring was done through actigraph and mood assessment was done by Profile of Mood States tool. The result of the study showed that adolescents were had greater feelings of anxiety, fatigue and confusion during sleep restriction condition compared to health sleep condition. Poor emotional regulation was also found during sleep restriction period. Hence, the study confirmed that sleep restriction adversely affects mood and emotional regulation capability of youth. The strength of the study is that it affirmed that severe duration of sleep restriction can worsen mood of adolescents. However, one limitation found in the study is that it restricted finding out other sleep environment factors that may affect sleep as it used actigraph to measure sleep duration.

Figure 1: Design Chart of Sleep manipulation protocol

Source: (Baum et al. 2014, pp.180-190)

Klumpers et al. (2015) also contributed useful information regarding effect of total sleep deprivation (TSD) on stress regulating brain systems. This study is useful for this literature review because unlike the above evidence, this study did research in adults. Klumpers et al. (2015) examined induction of fatigue and mood changes in sleep deprived person by examining changes in stress regulating brain systems fMRI based study. In response to the hypothesis of increase in dopamine release and cortisol awakening response due to TSD, the study showed that sleep deprivation induces neuro-physiological and endocrine changes in the brain. However, one limitation of the study was that dopaminergic system effect was not properly estimated and this gives direction for future research opportunities.

Impact of Sleep Deprivation on Mood

Conclusion:

The main purpose of the literature review was to explore different impact of sleep deprivation on body function. Conducting literature review in their area was considered important as sleep deprivation is becoming highly prevalent in adults now and seriously affecting health and longevity. The results from the literature review clearly gave the indication that metabolic functions, mood regulation and brain functions of individual is seriously affected when people circardian rhythm is disrupted. Considering the serious adverse effect of sleep deprivation on body system and health of affected individual, there is a need to make people aware about the important of health sleep routine and maintaining them in life to promote their health and well-being. 

Reference

Almklov, EL Drummond, SP Orff, H & Alhassoon, OM 2015, ‘The effects of sleep deprivation on brain functioning in older adults’, Behavioral sleep medicine, 13(4), 324-345.

Arble, DM, Bass, J Behn, CD Butler, MP Challet, E Czeisler, C ... & Hanlon, EC 2015, ‘Impact of sleep and circadian disruption on energy balance and diabetes: a summary of workshop discussions’, Sleep, 38(12), pp. 1849-1860.

Baum, KT Desai, A Field, J Miller, LE Rausch, J & Beebe, DW 2014, ‘Sleep restriction worsens mood and emotion regulation in adolescents’, Journal of Child Psychology and Psychiatry, 55(2), pp.180-190.

de Oliveira Otto, MC Padhye, NS Bertoni, AG Jacobs Jr, DR & Mozaffarian, D 2015, ‘Everything in moderation-dietary diversity and quality, central obesity and risk of diabetes’, PloS one, 10(10), p.e0141341.

del Angel, J Cortez, J Juárez, D Guerrero, M García, A Ramírez, C &Valdez, P 2015, ‘Effects of sleep reduction on the phonological and visuospatial components of working memory’, Sleep Science, 8(2), pp.68-74.

Howard, ME Jackson, ML Berlowitz, D O’Donoghue, F Swann, P Westlake, J Wilkinson, V & Pierce, RJ 2014, ‘Specific sleepiness symptoms are indicators of performance impairment during sleep deprivation’, Accident Analysis & Prevention, 62, pp.1-8.

Kim, TW Jeong, JH & Hong, SC 2015, ‘The impact of sleep and circadian disturbance on hormones and metabolism’, International journal of endocrinology, 2015.

Klumpers, UM Veltman, DJ van Tol, MJ Kloet, RW Boellaard, R Lammertsma, AA & Hoogendijk, WJ 2015, ‘Neurophysiological effects of sleep deprivation in healthy adults, a pilot study’, PloS one, 10(1), p.e0116906.

McEwen, BS & Karatsoreos, IN 2015, ‘Sleep deprivation and circadian disruption’ Sleep medicine clinics, 10(1), 1-10.

Nedeltcheva, AV & Scheer, FA, 2014, ‘Metabolic effects of sleep disruption, links to obesity and diabetes’, Current opinion in endocrinology, diabetes, and obesity, 21(4), p.293.

Vetter, C Devore, EE Ramin, C.A., Speizer, F.E., Willett, W.C. & Schernhammer, E.S., 2015, ‘Mismatch of sleep and work timing and risk of type 2 diabetes’, Diabetes Care, 38(9), pp.1707-1713.

Wright, K.P., Drake, A.L., Frey, D.J., Fleshner, M., Desouza, C.A., Gronfier, C. & Czeisler, C.A., 2015, ‘Influence of sleep deprivation and circadian misalignment on cortisol, inflammatory markers, and cytokine balance’, Brain, behavior, and immunity, 47, pp.24-34.