Sleep Deprivation and Its Effects - Research Paper Example

Introduction Sleep can be considered as an active process that cycles at an ultradian rhythm of about 90 minutes. Sleep is vital to regenerate certain parts of the body, especially the brain, in order to function optimally. Normal sleep is divided into non–rapid eye movement (NREM) and rapid eye movement (REM) sleep. The stages of sleep are stage I (light sleep), stage II, stages III and IV (deep or delta-wave sleep), and REM sleep; NREM sleep comprises stages I-IV. These five stages of sleep, including their repetition, occur in a cyclical fashion. The first cycle, which ends after the completion of the first REM stage, has a duration of about 100 minutes. Subsequently, each cycle lasts longer, as it’s respective REM stage extends. The normal progression of the sleep cycle can be affected by sleep deprivation, frequent change of sleep schedules, stress, and environment. Newborns have a total sleep duration of 14-16 hours in a day. When compared to any other age group, infants have an overall greater total sleep time. Adults require 8-8.4 hours of sleep, whereas the duration of stages III and IV sleep decreases by 10–15% in elderly persons. In infancy and early childhood, the percentage of REM sleep is highest, and it drops during adolescence and young adulthood, and decreases further in older age. Sleep deprivation can be considered as an overall lack of the required amount of sleep. Sleep deprivation can lead to neuronal malfunction, affecting the mood, metabolism, the endocrine system and other effects on the heart, immune system etc. Review of Literature Symptoms of Sleep Deprivation In adults, the symptoms of sleep deprivation include: frequent yawning, dozing off when inactive, grogginess on waking up in the morning, grogginess through out the day (sleep inertia), decreased concentration and increased irritability. In children, the symptoms of sleep deprivation include: moodiness, irritability, temper tantrums, hyperactivity, daytime naps, grogginess on waking up in the morning, and reluctance to wake up in the morning (Better Health Channel, 2005.) Causes of Sleep Deprivation The causes of sleep deprivation are varied, and include: staying up late in the night, conditions like rhinorrhoea and tonsillitis, which cause snoring, gagging and frequent waking, disruption of sleep-wake cycles in people who do shift work, erratic sleeping patterns in travelers, disturbed sleep due to conditions like sleep apnea, snoring and periodic limb movement disorder, insomnia due to medications or drinking coffee, and smoking cigarettes before bedtime (Better Health Channel, 2005.) General Effects of Sleep Deprivation In adults, the effects of sleep deprivation include: reduced alertness, short attention span, poor judgment, inability to take decisions, poor work efficiency, loss of motivation, errors of omission, errors of commission, and microsleep (brief involuntary sleeping, lasting from a few seconds to a few minutes in duration). The effects of sleep deprivation on children and teenagers include: problems at school, depression and attention deficit hyperactivity disorder (ADHD) (Better Health Channel, 2005.) Effects of Sleep Deprivation on the Brain Researchers at the UCSD School of Medicine and the Veterans Affairs Healthcare System, San Diego, used functional magnetic resonance imaging (fMRI) to monitor brain activity in thirteen, normal and healthy, sleep-deprived subjects when they were performing simple verbal learning tasks. After first evaluating them in a sleep laboratory to know if their sleep patterns were normal, they were then kept awake and monitored for a period of 35 hours. FMRI scans were performed when separate cognitive tasks were given to the subjects. The images obtained from the scan revealed that the prefrontal cortex (PFC) region of the brain displayed more activity, which directly correlated with the degree of sleepiness; when the subjects felt sleepier, the PFC was more active. The temporal lobe, which is involved in language processing, was not activated in sleep-deprived subjects. The parietal lobes were also more active in the sleep-deprived subjects. Sleep deprivation also decreased the subjects’ memory performance. From this study, it can be concluded that in a sleep-deprived state, the brain makes a dynamic effort to function, although the consequence of this is a decreased ability to perform basic cognitive tasks. In addition, the effect of sleep loss is different, and depends on the cognitive task the brain is required to perform (UCSD Medical Center, 2000.) Normal sleep is associated with better academic performance and learning abilities. Both quality and quantity of sleep are important in the learning capacity and academic performance of students. Many students are chronically deprived of sleep or suffer from poor sleep quality. This is frequently associated with poor neurocognitive and academic performance, and is related to the specific involvement of the prefrontal cortex (PFC) in sleep deprivation. (Curcio et al., 2006 ). Sleep deprivation in adolescents Adolescents are biologically required to sleep longer and later when compared to adults, and the effects of sleep deprivation are more pronounced than that in adults. Studies conducted over the past two decades have shown that teenagers require about 9.2 hours of sleep each night, when compared to 8-8.4 hours that adults require. In addition to this, adolescents experience a "phase shift" during puberty. This involves falling asleep later at night than younger children. This "phase shift" is not only due to psychosocial factors such as social activities, academic pressures, evening jobs and television and Internet use but also due to their unique biology. Adolescent sleep deprivation is often associated with psychopathologies like depression and attention deficit hyperactivity disorder (ADHD). In addition, it can lead to accidents, poor grades at school and lead to or exacerbate emotional problems (Carpenter, 2001) Effects of Sleep deprivation on Safety The Federal Highway Administrations (FHWA), Human Factors Laboratory and the Walter Reed Army Institute of Researchs (WRAIR) conducted a joint study on the effects of partial and total sleep deprivation on driving performance. This laboratory conducted study, examined the effects of progressive sleep deprivation on simulated driving performance, in order to assess the rate of accidents and changes in driving performance resulting from sleepiness. It was observed that there was a small increase in accident rates after a moderate reduction in the previous nights sleep (4h-8h), and a marked increase with progressive sleep deprivation. The results of the driving data confirmed that sleepiness is a important factor, which leads to off-road accidents (Peters, et al., n.d). One study has found that people who drive after being sleep deprived for 17 to 19 hours performed worse than those with a blood alcohol level of .05 percent (Hassen F, 2002.) Sleeping for less than 6 hours a night can affect coordination, reaction time and judgment. People who are required to do long shifts or night shifts, like medical personnel or other emergency workers, may have reduced motor skills, in addition to having higher levels of stress, anxiety and depression, and the tendency to take unnecessary risks (CNN.com, 2001.) Sleep deprivation can lead to serious industrial accidents. Sleep deprivation can reduce alertness and vigilance by 50 percent, decision-making ability by 50 percent, communication skills by 30 percent, and memory by 20 percent (Hassen F, 2002.) Metabolic and Endocrine Effects of Sleep Deprivation Sleep deprivation causes a rise in the level of cortisol in the afternoon and early evening, which can lead to disturbances like memory deficits, similar to those observed in aging. Therefore, chronic sleep loss could accelerate the aging process. Sleep deprivation leads to impaired carbohydrate tolerance, and chronic sleep deprivation may increase the risk for diabetes. Partial sleep deprivation is associated with decreased plasma levels of leptin and increased plasma levels of ghrelin. In addition, hunger and appetite is also increased. Sleep deprivation may therefore, lead to obesity (Copinschi, 2005.) Vgontzas et al (1999) in their study assessed the effects of sleep deprivation on cortisol and growth hormone (GH) secretion the next day and recovery night. Measurements included serial twenty-four hour blood sampling, eight-hour sleep laboratory recording, including electroencephalogram, electro-oculogram and electromyogram, and measurement of plasma cortisol and GH levels using specific immunoassay techniques. They concluded from the results that sleep deprivation results in a significant reduction of cortisol secretion the next day. To a large extent, this reduction in cortisol secretion seems to be influenced by the increase of slow wave sleep during the recovery night. Disturbed sleep also has a stimulatory effect on the HPA axis and a suppressive effect on the GH axis. They further proposed that the mechanism by which sleep deprivation relieves depression temporarily is due to a reduction of CRH and cortisol secretion. The release of the hormone thyrotropin (TSH), which regulates the thyroid hormones, thyroxine (T4), and triiodothyronine (T3) is due to circadian and sleep components. Gary et al (1996) examined the concentrations of TSH, T4, and T3 across the wake-sleep boundary time (2300-0130 hours) before, during, and after a 64-hour sleep deprivation. It was found that sleep deprivation was associated with elevated levels of TSH. Sleep Deprivation and Depression Persistent sleep disturbances have been associated with a high risk of relapse and recurrence of mood disorders and an increased risk of suicide ( Holsboer-Trachsler & Seifritz, 2000.) Ironically, total sleep deprivation (TSD) has been used along with medications in the treatment of major depression. Although the exact mechanism of how TSD helps in major depression is not clear, current theories propose that TSD enhances dopamine activity, which counteracts the depression (Benedetti et al., 2001). However, there is only a short-lasting improvement of depressive symptoms due to sleep deprivation (Nissen et al., 2001.) Other Effects of Sleep Deprivation Disturbed sleep can cause or modulate acute and chronic pain. Many studies have shown that sleep deprivation produces hyperalgesic changes (Lautenbacher, Kundermann & Krieg, 2005). Sleep deprivation may also disrupt visual tasks, especially identifying shapes (Raidy & Scharff, 2005) Sleep deprivation decreases core body temperature, decreases immune system function, and increased heart rate variability (Russo, 2005.) Prolonged and severe sleep deprivation can alter natural and cellular immune function. One study (Irwin M, et al., 1996) found that after a night of sleep deprivation, there was a reduction of NK (natural killer) cell activity, NK activity per number of NK cells, LAK (lymphokine-activated killer cell) activity, and LAK activity per number of LAK precursors (CD16, 56, CD25). Conclusion Normal sleep is vital for the body to rest and make any necessary repairs from illness, injury, and from the stress of daily life. Sleep is important for consolidating memories and in the regeneration and growth of the body. Sleep deprivation can be considered as an overall reduction of the required amount of sleep, which may be partial or total sleep deprivation. The causes and symptoms of sleep deprivation are varied. The specific effects of sleep deprivation on various systems have been researched by various studies. The effects on the brain include an increased activity of the prefrontal cortex, reduced memory and decreased ability to perform cognitive tasks. In the endocrine system, sleep deprivation causes a rise in the level of cortisol in the afternoon and early evening but a significant reduction of cortisol secretion the next day. The aging process may be accelerated. There is decreased plasma levels of leptin and increased plasma levels of ghrelin. Sleep deprivation stimulates the HPA axis and suppresses the GH axis, whereas the levels of TSH are elevated. The metabolic effects of sleep deprivation include an increased risk of developing diabetes and obesity. Although chronic sleep disturbance can lead to a high risk of relapse and recurrence of mood disorders and an increased risk of suicide, total sleep deprivation (TSD) has been used along with medications in the treatment of major depression. The other effects of sleep deprivation includes a reduction of core body temperature, decreased immune system function, increased heart rate variability, hyperalgesic changes, disruption of visual tasks, decreased motor skills, higher incidence of driving accidents, serious industrial accidents and various problems in adolescents like depression, ADHD and poor grades. Sleep deprivation can also lead to decreased work productivity and efficiency. This can translate into economic loss and increased financial burden. It is therefore clear that sleep deprivation has numerous detrimental effects on the body and can affect all age groups. Normal sleep is essential for the proper functioning of the various systems of the body, for better efficiency, productivity and a healthier life. ************************************************************************************************* References Better Health Channel (2005). Sleep deprivation. 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