Sleep deprivation
Sleep deprivation is the condition of not having enough sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...

; it can be either chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...

 or acute
Acute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....

. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the effects of acute total sleep deprivation and chronic partial sleep restriction. Complete absence of sleep over long periods is impossible for humans to achieve (unless they suffer from fatal familial insomnia
Fatal familial insomnia
Fatal familial insomnia is a very rare autosomal dominant inherited prion disease of the brain. It is almost always caused by a mutation to the protein PrPC, but can also develop spontaneously in patients with a non-inherited mutation variant called sporadic fatal insomnia...

); brief microsleep
A microsleep is an episode of sleep which may last for a fraction of a second or up to thirty seconds. Often, it is the result of sleep deprivation, mental fatigue, depression, sleep apnea, hypoxia, narcolepsy, or hypersomnia...

s cannot be avoided. Long-term total sleep deprivation has caused death in lab animals.

Physiological effects

Generally, sleep deprivation may result in:
  • aching muscles
  • confusion, memory
    In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

     lapses or loss
  • depression
    Depression (mood)
    Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...

  • hallucinations
  • hand tremor
    A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...

  • headaches
  • malaise
    Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...

  • sensitivity to cold
  • bloodshot eyes
    Red eye (medicine)
    In medicine, red eye is a non-specific term to describe an eye that appears red due to illness, injury, or some other condition. Conjunctivitis and subconjunctival hemorrhage are two forms of a red eye....

  • periorbital puffiness, commonly known as "bags under eyes" or eye bags
  • increased blood pressure
  • increased stress hormone levels
  • increased risk of diabetes
  • increased risk of fibromyalgia
    Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...

  • irritability
    Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....

  • nystagmus
    Nystagmus is a condition of involuntary eye movement, acquired in infancy or later in life, that may result in reduced or limited vision.There are two key forms of Nystagmus: pathological and physiological, with variations within each type. Nystagmus may be caused by congenital disorders,...

    (rapid involuntary rhythmic eye movement)
  • obesity
    Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

  • temper tantrums in children
  • yawn
    A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Pandiculation is the act of yawning and stretching simultaneously....

  • symptoms similar to:
    • Attention-deficit hyperactivity disorder
      Attention-deficit hyperactivity disorder
      Attention deficit hyperactivity disorder is a developmental disorder. It is primarily characterized by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age.ADHD is the most commonly studied and...

    • Psychosis
      Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...


In 2005, a study of over 1400 participants showed that participants who habitually slept few hours were more likely to have associations with diabetes type 2. However, because this study was merely correlational, the direction of cause and effect between little sleep and diabetes is uncertain. The authors point to an earlier study which showed that experimental rather than habitual restriction of sleep resulted in impaired glucose tolerance
Impaired glucose tolerance
Impaired glucose tolerance is a pre-diabetic state of dysglycemia that is associated with insulin resistance and increased risk of cardiovascular pathology. IGT may precede type 2 diabetes mellitus by many years...


Effects on the brain

Sleep deprivation can adversely affect the brain and cognitive function. A 2000 study, by the UCSD School of Medicine and the Veterans Affairs Healthcare System in San Diego, used functional magnetic resonance imaging
Functional magnetic resonance imaging
Functional magnetic resonance imaging or functional MRI is a type of specialized MRI scan used to measure the hemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...

 (fMRI) technology to monitor activity in the brains of sleep-deprived subjects performing simple verbal learning tasks. The study showed that regions of the brain's prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...

 displayed more activity in sleepier subjects. Depending on the task at hand, the brain would sometimes attempt to compensate for the adverse effects caused by sleep deprivation.

The temporal lobe
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....

, which is a brain region involved in language processing, was activated during verbal learning in rested subjects but not in sleep-deprived subjects. The parietal lobe
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...

, not activated in rested subjects during the verbal exercise, was more active when the subjects were deprived of sleep. Although memory performance was less efficient with sleep deprivation, greater activity in the parietal region was associated with better short term memory.

A 2001 study at Chicago Medical Institute suggested that sleep deprivation may be linked to serious diseases, such as heart disease and mental illnesses including psychosis and bipolar disorder
Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...

. The link between sleep deprivation and psychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...

 was further documented in 2007 through a study at Harvard Medical School and the University of California at Berkeley. The study revealed, using MRI scans, that sleep deprivation causes the brain to become incapable of putting an emotional event into the proper perspective and incapable of making a controlled, suitable response to the event. Sleep deprivation may have been the underlying cause of the overdose deaths of celebrities Heath Ledger
Heath Ledger
Heath Andrew Ledger was an Australian television and film actor. After performing roles in Australian television and film during the 1990s, Ledger moved to the United States in 1998 to develop his film career...

, and Anna Nicole Smith
Anna Nicole Smith
In 1992 Smith was chosen by Hugh Hefner to appear on the cover of the March issue of Playboy, where she was listed as Vickie Smith, wearing a low-cut evening gown. The centerfold was photographed by Stephen Wayda. Smith said she planned to be "the next Marilyn Monroe". Becoming one of Playboys...


A study tested 17 right-handed civilian males, between the ages of 21–29 years (mean 24.7 ± 2.8 years), with no history of medical, neurological, psychiatric, or sleep disorder conditions. Their histories also included 7–8 h of nightly sleep on a regular basis, no nicotine use, and low caffeine use (less than 100 mg/day).
The negative effects of sleep deprivation on alertness and cognitive performance suggest decreases in brain activity and function, primarily in the thalamus, structure involved in alertness and attention, and in the prefrontal cortex, a region sub-serving alertness, attention, and higher-order cognitive processes.

This study used a combination of positron emission tomography (PET) and Fluorine-2-deoxyglucose (FDG), a marker for regional cerebral metabolic rate for glucose (CMRglu) and neuronal synaptic activity.A time series design was used, with progressive sleep deprivation as the independent variable. Repeated measures of absolute regional CMRglu, cognitive performance, alertness, mood, and subjective experiences were collected after 0, 24, 48, and 72 h of sleep deprivation. Additional measures of alertness, cognitive performance, and mood were collected at fixed intervals throughout the sleep deprivation period. These measures were included to place the performance results associated with the PET scans in the context of the circadian rhythm of cognitive performance, as well as to impose a moderate-to-heavy near continuous workload on the subjects as might be anticipated in a real-world sustained operation.

A noted 2002 University of California animal study indicated that non-rapid eye movement sleep (NREM) is necessary for turning off neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

s and allowing their receptors to "rest" and regain sensitivity which allows monoamines (norepinephrine, serotonin and histamine) to be effective at naturally-produced levels. This leads to improved regulation of mood and increased learning ability. The study also found that rapid eye movement sleep (REM) deprivation may alleviate clinical depression because it mimics selective serotonin reuptake inhibitors (SSRIs). This is because the natural decrease in monoamines during REM is not allowed to occur, which causes the concentration of neurotransmitters in the brain, that are depleted in clinically depressed persons, to increase. Sleep outside of the REM phase may allow enzymes to repair brain cell damage caused by free radicals
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...

. High metabolic activity while awake damages the enzymes themselves preventing efficient repair. This study observed the first evidence of brain damage in rats as a direct result of sleep deprivation.

Animal studies suggest that sleep deprivation increases stress hormone
Stress hormone
Stress hormones such as cortisol, GH and norepinephrine are released at periods of high stress. The hormone regulating system is known as the endocrine system...

s, which may reduce new cell production in adult brains.

Effects on growth

A 1999 study found that sleep deprivation resulted in reduced cortisol
Cortisol is a steroid hormone, more specifically a glucocorticoid, produced by the adrenal gland. It is released in response to stress and a low level of blood glucocorticoids. Its primary functions are to increase blood sugar through gluconeogenesis; suppress the immune system; and aid in fat,...

 secretion the next day, driven by increased subsequent slow-wave sleep. Sleep deprivation was found to enhance activity on the hypothalamic-pituitary-adrenal axis (which controls reactions to stress and regulates body functions such as digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

, the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

, mood
Mood (psychology)
A mood is a relatively long lasting emotional state. Moods differ from emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event....

, sex, or energy usage) while suppressing growth hormones. The results supported previous studies, which observed adrenal insufficiency in idiopathic hypersomnia
Hypersomnia is a disorder characterized by excessive amounts of sleepiness.There are two main categories of hypersomnia: primary hypersomnia and recurrent hypersomnia...


Effects on the healing process

A study conducted in 2005 showed that a group of rats which were deprived of REM sleep for five days had no significant effect on their ability to heal wounds, compared to a group of rats not deprived of "dream" sleep. The rats were allowed deep (NREM) sleep. However, another study conducted by Gumustekin et al. in 2004 showed sleep deprivation hindering the healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....

 of burns on rats.

Attention and working memory

Among the numerous physical consequences of sleep deprivation, deficits in attention and working memory are perhaps the most important; such lapses in mundane routines can lead to unfortunate results, from forgetting ingredients while cooking to missing a sentence while taking notes. Working memory is tested by such methods as choice-reaction time tasks.

The attentional lapses also extend into more critical domains in which the consequences can be literally life-or-death; car crashes and industrial disasters can result from inattentiveness attributable to sleep deprivation. To empirically measure the magnitude of attention deficits, researchers typically employ the psychomotor vigilance task
Psychomotor vigilance task
The Psychomotor Vigilance Task is a sustained-attention, reaction-timed task that measures the speed with which subjects respond to a visual stimulus. Quantitative dependent variables involve omission and commission errors, reflecting fluctuations in endogenous cognitive condition...

 (PVT) which requires the subject to press a button in response to a light at pseudo-random intervals. Failure to press the button in response to the stimulus (light) is recorded as an error, attributable to the microsleeps that occur as a product of sleep deprivation.

Crucially, individuals' subjective evaluations of their fatigue often do not predict actual performance on the PVT. While totally sleep-deprived individuals are usually aware of the degree of their impairment, lapses from chronic (lesser) sleep deprivation can build up over time so that they are equal in number and severity to the lapses occurring from total (acute) sleep deprivation. Chronically sleep-deprived people, however, continue to rate themselves considerably less impaired than totally sleep-deprived participants. Since people usually evaluate their capability on tasks like driving subjectively, their evaluations may lead them to the false conclusion that they are able to perform tasks that require constant attention when their abilities are in fact impaired.

Impairment of ability

The dangers of sleep deprivation are apparent on the road; the American Academy of Sleep Medicine
American Academy of Sleep Medicine
The American Academy of Sleep Medicine is a United States professional society for the medical subspecialty of sleep medicine. It was established in 1975. The AASM is the only professional society that is dedicated exclusively to the medical subspecialty of sleep medicine...

 (AASM) reports that one in every five serious motor vehicle injuries is related to driver fatigue, with 80,000 drivers falling asleep behind the wheel every day and 250,000 accidents every year related to sleep, though the National Highway Traffic Safety Administration suggests the figure for traffic accidents may be closer to 100,000. The AASM recommends pulling off the road and taking a 15- or 20-minute nap to alleviate drowsiness.

According to a 2000 study published in the British Medical Journal
British Medical Journal
BMJ is a partially open-access peer-reviewed medical journal. Originally called the British Medical Journal, the title was officially shortened to BMJ in 1988. The journal is published by the BMJ Group, a wholly owned subsidiary of the British Medical Association...

, researchers in Australia and New Zealand reported that sleep deprivation can have some of the same hazardous effects as being drunk. People who drove after being awake for 17–19 hours performed worse than those with a blood alcohol level of .05 percent, which is the legal limit for drunk driving in most western European countries and Australia. Another study suggested that performance begins to degrade after 16 hours awake, and 21 hours awake was equivalent to a blood alcohol content of .08 percent, which is the blood alcohol limit for drunk driving in Canada, the U.S., and the U.K.

In addition, as a result of continuous muscular activity without proper rest time, effects such as cramping are much more frequent in sleep-deprived individuals. Extreme cases of sleep deprivation have been reported to be associated with hernias, muscle fascia tears, and other such problems commonly associated with physical overexertion.

A 2006 study has shown that while total sleep deprivation for one night caused many errors, the errors were not significant until after the second night of total sleep deprivation. However, combining alcohol with acute sleep deprivation results in a trebled rate of driving off the road when using a simulator.

The National Sleep Foundation identifies several warning signs that a driver is dangerously fatigued, including rolling down the window, turning up the radio, trouble keeping eyes open, head-nodding, drifting out of the lane, and daydreaming. At particular risk are lone drivers between midnight and 6 a.m.

Sleep deprivation can negatively impact performance in professional fields as well, potentially jeopardizing lives. Due largely to the February 2009 crash of a regional jet in Buffalo, NY, which killed 50 people and was partially attributed to pilot fatigue, the FAA is reviewing its procedures to ensure pilots are sufficiently rested. A 2004 study also found medical residents with less than four hours of sleep a night made more than twice as many errors as residents who slept for more than seven hours a night, an especially alarming trend given that less than 11% of surveyed residents were sleeping more than seven hours a night.

Twenty-four hours of continuous sleep deprivation results in the choice of less difficult math tasks without decreases in subjective reports of effort applied to the task. Naturally-caused sleep loss affects the choice of everyday tasks such that low effort tasks are mostly commonly selected. Adolescents who experience less sleep show a decreased willingness to engage in sports activities that require effort through fine motor coordination and attention to details.

Great sleep deprivation mimics psychosis: distorted perceptions can lead to inappropriate emotional and behavioral responses.


A microsleep is an episode of sleep which may last for a fraction of a second or up to thirty seconds. Often, it is the result of sleep deprivation, mental fatigue, depression, sleep apnea, hypoxia, narcolepsy, or hypersomnia...

s occur when a person has a significant sleep deprivation. The brain automatically shuts down, falling into a sleep state for a period that can last from a second to half a minute. The person falls asleep no matter what activity he or she is engaged in. Microsleeps are similar to blackouts
Syncope (medicine)
Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...

 and a person experiencing them is not consciously aware that they are occurring.

An even lighter type of sleep has been seen in rats that have been kept awake for long. Local regions went into periods of short (~80 ms) but frequent (~40/min) NREM-like state. Despite the on and off periods where neurons shut off, the rats appeared awake, although they performed worse at tests.

Weight gain/loss

In rats, prolonged, complete sleep deprivation increased both food intake and energy expenditure with a net effect of weight loss and ultimately death. This study hypothesizes that the moderate chronic sleep debt associated with habitual short sleep is associated with increased appetite and energy expenditure with the equation tipped towards food intake rather than expenditure in societies where high-calorie food is freely available.

Several large studies using nationally representative samples suggest that the obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

 problem in the United States might have as one of its causes a corresponding decrease in the average number of hours that people are sleeping. The findings suggest that this might be happening because sleep deprivation could be disrupting hormones that regulate glucose metabolism and appetite.

The association between sleep deprivation and obesity appears to be strongest in young and middle-age adults. Other scientists hold that the physical discomfort of obesity and related problems, such as sleep apnea
Sleep apnea
Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour. Similarly, each abnormally low...

, reduce an individual's chances of getting a good night's sleep.

Sleep loss is currently proposed to disturb endocrine regulation of energy homeostasis leading to weight gain and obesity.
A reduction of sleep duration to 4 h for two consecutive nights has recently been shown to decrease circulating leptin levels and to increase ghrelin levels, as well as self-reported hunger. Similar endocrine alterations have been shown to occur even after a single night of sleep restriction.

In a balanced order, nine healthy normal-weight men spent three nights in a sleep laboratory separated by at least 2 weeks: one night with a total sleep time of 7 h, one night with a total sleep time of 4.5 h, and one night with total sleep deprivation (SD).
On a standard symptom-rating scale, subjects rated markedly stronger feelings of hunger after total SD than after 7 h sleep (3.9 +/- 0.7 versus 1.7 +/- 0.3; P = 0.020) or 4.5 h sleep (2.2 +/- 0.5; P = 0.041). Plasma ghrelin levels were 22 +/- 10% higher after total SD than after 7 h sleep (0.85 +/- 0.06 versus 0.72 +/- 0.04 ng mL(-1); P = 0.048) with intermediate levels of the hormone after 4.5 h sleep (0.77 +/- 0.04 ng mL(-1)).
Feelings of hunger as well as plasma ghrelin levels are already elevated after one night of SD, whereas morning serum leptin concentrations remain unaffected. Thus, the results provide further evidence for a disturbing influence of sleep loss on endocrine regulation of energy homeostasis, which in the long run may result in weight gain and obesity.

Scientific study of laboratory animals

In science, sleep deprivation (of rodents, e.g.) is used in order to study the function(s) of sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...

 and the biological mechanisms underlying the effects of sleep deprivation.

Some sleep deprivation techniques are as follows:
  • Gentle handling: During the sleep deprivation period, the animal and its polysomnograph record are continuously observed; when the animal displays sleep electrophysiological signals or assumes a sleep posture, it is given objects to play with and activated by acoustic and if necessary tactile stimuli. Although subjective, this technique is used for total sleep deprivation as well as REM or NREM
    Non-rapid eye movement, or NREM is, collectively, sleep stages 1 – 3, previously known as stages 1 – 4. Rapid eye movement sleep is not included. There are distinct electroencephalographic and other characteristics seen in each stage. Unlike REM sleep, there is usually little or no eye movement...

     sleep deprivation. This technique often requires polysomnography
    Polysomnography , also known as a sleep study, is a multi-parametric test used in the study of sleep and as a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG...

  • Single platform: During the sleep deprivation period, the animal is placed on an inverted flower pot, the bottom diameter of which is small relative to the animal's size (usually 7 cm for adult rats). The pot is placed in a large tub filled with water to within 1 cm of the flower pot bottom. The animal is able to rest on the pot and is even able to get NREM sleep. But at the onset of REM sleep, with its ensuing muscular relaxation, it will either fall into the water and clamber back to its pot or will get its nose wet enough to awaken it. Thus, this technique is only useful for studying REM sleep deprivation. This was one of the first scientific methods developed (see Jouvet, 1964 for cats and for rodents).
  • Multiple platform: In an effort to reduce the elevated stress response induced by the single platform method, researchers developed the "multiple platform" technique of REM sleep deprivation. In this configuration, the animal is placed within a large tank containing multiple platforms, thereby eliminating the movement restriction in the earlier setup.
  • Modified multiple platform: Modification of the multiple platform method where several animals together experience sleep deprivation (Nunes and Tufik, 1994).
  • Pendulum: Animals are prevented from entering into REM sleep by allowing them to sleep for only brief periods of time. This is accomplished by an apparatus that moves the animals' cages backwards and forwards in a pendular motion
    A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced from its resting equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position...

    . At the extremes of the motion, the animals experience postural imbalance, forcing them to walk back and forth to retain their balance.


Sleep deprivation can be used as a means of interrogation, which has resulted in court trials over whether or not the technique is a form of torture.

Under one interrogation technique, a subject might be kept awake for several days and when finally allowed to fall asleep, suddenly awakened and questioned. Menachem Begin
Menachem Begin
' was a politician, founder of Likud and the sixth Prime Minister of the State of Israel. Before independence, he was the leader of the Zionist militant group Irgun, the Revisionist breakaway from the larger Jewish paramilitary organization Haganah. He proclaimed a revolt, on 1 February 1944,...

, the Prime Minister of Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

 from 1977–83, described his experience of sleep deprivation as a prisoner of the NKVD
The People's Commissariat for Internal Affairs was the public and secret police organization of the Soviet Union that directly executed the rule of power of the Soviets, including political repression, during the era of Joseph Stalin....

 in Russia as follows:
Sleep deprivation was one of the five techniques
Five techniques
The term five techniques refers to certain interrogation practices adopted by the Northern Ireland and British governments during Operation Demetrius in the early 1970s...

 used by the British government in the 1970s. The European Court of Human Rights
European Court of Human Rights
The European Court of Human Rights in Strasbourg is a supra-national court established by the European Convention on Human Rights and hears complaints that a contracting state has violated the human rights enshrined in the Convention and its protocols. Complaints can be brought by individuals or...

 ruled that the five techniques "did not occasion suffering of the particular intensity and cruelty implied by the word torture ... [but] amounted to a practice of inhuman and degrading treatment", in breach of the European Convention on Human Rights
European Convention on Human Rights
The Convention for the Protection of Human Rights and Fundamental Freedoms is an international treaty to protect human rights and fundamental freedoms in Europe. Drafted in 1950 by the then newly formed Council of Europe, the convention entered into force on 3 September 1953...


The United States Justice Department released four memos in August 2002 describing interrogation techniques used by the Central Intelligence Agency. They first described 10 techniques used in the interrogations of Abu Zubaydah. Among them included sleep deprivation. Memos from May 2005 introduced four more techniques and confirmed the combination of interrogation methods were not constituted as torture under United States law.

The question of extreme use of sleep deprivation as torture has advocates on both sides of the issue. In 2006, Australian Federal Attorney-General Philip Ruddock
Philip Ruddock
Philip Maxwell Ruddock is an Australian politician who is currently a member of the House of Representatives representing the Division of Berowra, New South Wales, for the Liberal Party of Australia...

 argued that sleep deprivation does not constitute torture. Nicole Bieske, a spokeswoman for Amnesty International Australia, has stated, "At the very least, sleep deprivation is cruel, inhumane and degrading. If used for prolonged periods of time it is torture."

Treatment for depression

Recent studies show sleep deprivation has some potential in the treatment of depression. As many as 60% of patients, when sleep-deprived, show immediate recovery, although most relapse the following night. The effect has been shown to link to increases in brain-derived neurotrophic factor
Brain-derived neurotrophic factor
Brain-derived neurotrophic factor, also known as BDNF, is a protein that, in humans, is encoded by the BDNF gene. BDNF is a member of the "neurotrophin" family of growth factors, which are related to the canonical "Nerve Growth Factor", NGF...

 (BDNF). It has been shown that chronotype
Chronotype is an attribute of animals, including human beings, reflecting at what time of the day their physical functions are active, change or reach a certain level...

 is related to the effect of sleep deprivation on mood in normal people; those with morningness circadian preference show an increase in depression-dejection scores while those with eveningness preference show a significant decrease.

The incidence of relapse can be decreased by combining sleep deprivation with medication. Many tricyclic antidepressants happen to suppress REM sleep, providing additional evidence for a link between mood
Mood (psychology)
A mood is a relatively long lasting emotional state. Moods differ from emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event....

 and sleep. Similarly, tranylcypromine
Tranylcypromine is a drug of the substituted phenethylamine and amphetamine classes which acts as a monoamine oxidase inhibitor —it is a non-selective and irreversible inhibitor of the enzyme monoamine oxidase...

 has been shown to completely suppress REM sleep at adequate doses.


Sleep deprivation can sometimes be self-imposed due to a lack of desire to sleep and/or the habitual use of stimulant drugs (i.e Cocaine, Amphetamines, etc.) Recent studies have also suggested that sleep deprivation produces similar effects in the brain to that of an SSRI in persons with depression, thus insuing a clinical, self-imposed remedy. However, most individuals suffering from clinical depression are not aware that lack of sleep is having a direct positive effect on thinking. Sleep deprivation is also self imposed to achieve personal notoriety in the context of record-breaking stunts
World record
A world record is usually the best global performance ever recorded and verified in a specific skill or sport. The book Guinness World Records collates and publishes notable records of all types, from first and best to worst human achievements, to extremes in the natural world and beyond...

. Voluntary sleep deprivation is also utilized in the converting from monophasic sleep to polyphasic sleep
Polyphasic sleep
Polyphasic sleep, a term coined by early 20th-century psychologist J.S. Szymanski, refers to the practice of sleeping multiple times in a 24-hour period—usually more than two, in contrast to biphasic sleep or monophasic sleep . It does not imply any particular sleep schedule...


Sleep apnea

Sleep apnea
Sleep apnea
Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour. Similarly, each abnormally low...

 or an obstructive airway disorder reduces the correct amount of airflow. Nasal problems such as a deviated septum will shut down the airway and increase swelling in the mucus lining and nasal turbinates. Corrective surgery (septoplasty
Septoplasty is a corrective surgical procedure done fix to straighten the nasal septum, the partition between the two nasal cavities. Ideally, the septum should run down the center of the nose. When it deviates into one of the cavities, it narrows that cavity and impedes airflow. Often the...

) will maximise the airflow and correct the feedback loop to the brain which keeps the sufferer awake so as not to asphyxiate.

Psychostimulant drugs

Psychostimulant drugs, predominantly methamphetamine
Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...

, are capable of keeping users awake for 3–15 days at a time with repeated dosing.

Mental illness

The specific causal relationships between sleep loss and effects on psychiatric disorders have been most extensively studied in patients with mood disorders. Shifts into mania in bipolar patients are often preceded by periods of insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...

, and sleep deprivation has been shown to induce a manic state in susceptible individuals. Sleep deprivation may represent a final common pathway in the genesis of mania, and sleep loss is both a precipitating and reinforcing factor for the manic state.


A National Sleep Foundation
National Sleep Foundation
The National Sleep Foundation is an independent nonprofit organization in the USA whose objectives are to improve public health and safety by achieving understanding of sleep and sleep disorders, and to support sleep-related education, research, and advocacy.Established in 1990, the NSF relies on...

 survey found that college/university-aged students get an average of 6.7 hours of sleep each night. Sleep deprivation is common in first year college students as they adjust to the stress and social activities of college life. A study performed by the Department of Psychology at the National Chung Cheng University
National Chung Cheng University
National Chung Cheng University , abbreviated CCU, is a public research university located in Minhsiung, Chiayi County, Taiwan. It is distinctive among universities in Taiwan in that it is dedicated to the core humanities and the basic sciences, both natural and social...

 in Taiwan concluded that freshmen received the shortest amount of sleep during the week. In 1997 the University of Minnesota
University of Minnesota
The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...

 did research that compared students who went to school at 7:15 a.m. and those who went to school at 8:40 a.m. They found that students who went to school at 8:40 got higher grades and more sleep on weekday nights. One in four U.S. high school students admits to falling asleep in class at least once a week. It is known that during human adolescence, circadian rhythm
Circadian rhythm
A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...

s and therefore sleep patterns typically undergo marked changes. Electroencephalogram (EEG) studies indicate a 50% reduction of deep (stage 4) sleep and a 75% reduction in the peak amplitude of delta waves during NREM sleep in adolescence. School schedules are often incompatible with a corresponding delay in sleep offset, leading to a less than optimal amount of sleep for the majority of adolescents.

Counteracting the effects of sleep deprivation

Several strategies are common in attempting to increase alertness and counteract the effects of sleep deprivation. Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

 is often used over short periods to boost wakefulness when acute sleep deprivation is experienced; however, caffeine is less effective if taken routinely. Other strategies recommended by the American Academy of Sleep Medicine include prophylactic sleep before deprivation, naps, other stimulants, and combinations thereof. However, the only sure and safe way to combat sleep deprivation is to increase nightly sleep time.

Recovery of cognitive function is accomplished more rapidly after acute total sleep deprivation than after chronic partial sleep restriction. Chronic deprivation is the more common in everyday life. Just one night of recovery sleep can reverse adverse effects of total sleep deprivation. Recovery sleep is more efficient than normal sleep with shorter sleep latency and increased amounts of deep and REM sleep.

Longest period without sleep

Randy Gardner holds the scientifically documented record for the longest period of time a human being has intentionally gone without sleep not using stimulants of any kind. Gardner stayed awake for 264 hours (11 days), breaking the previous record of 260 hours held by Tom Rounds of Honolulu. Lt. Cmdr. John J. Ross of the U.S. Navy Medical Neuropsychiatric Research Unit later published an account of this event, which became well-known among sleep-deprivation researchers.

Other sources claim that the Guinness World Records record stands at 449 hours (18 days, 17 hours), held by Maureen Weston, of Peterborough, Cambridgeshire in April, 1977, in a rocking-chair marathon.

Claims of not having slept in years have been made at times, for certain individuals, but either without scientific verification, or contradicted in independent verification:
  • Never scientifically verified: Thai Ngoc
    Thai Ngoc
    Thai Ngoc or Hai Ngoc is a Vietnamese insomniac. According to Vietnamese news organization Thanh Nien, he is best known for his claim of being awake for 38 years. Thanh Nien also claimed that Ngoc acquired the ability to go without sleep after a bout of fever in 1973, but according to the Vietnam...

    , born 1942, claimed in 2006 to have been awake for 33 years or 11,700 nights, according to Vietnam
    Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

    ese news organization Thanh Nien. It was said that Ngoc acquired the ability to go without sleep after a bout of fever in 1973, but other reports indicate he stopped sleeping in 1976 with no known trigger. At the time of the Thanh Nien report, Ngoc suffered from no apparent ill effect (other than a minor decline in liver function), was mentally sound and could carry 100 kg of pig feed down a 4 km road, but another report indicates that he was healthy before the sleepless episode but that now he was not feeling well because of sleep deprivation.
  • Contradicted by claimant himself: In January 2005, the RIA Novosti published an article about Fyodor Nesterchuk from the Ukrainian
    Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

     town of Kamen-Kashirsky who claimed to have not slept in more than 20 years. Local doctor Fyodor Koshel, chief of the Lutsk
    Lutsk is a city located by the Styr River in northwestern Ukraine. It is the administrative center of the Volyn Oblast and the administrative center of the surrounding Lutskyi Raion within the oblast...

     city health department, claimed to have examined him extensively and failed to make him sleep. Koshel also said however that Nesterchuck did not suffer any of the normally deleterious effects of sleep deprivation. However, when a reporter from The Guardian
    The Guardian
    The Guardian, formerly known as The Manchester Guardian , is a British national daily newspaper in the Berliner format...

    followed up on this report, Nesterchuk said he was getting 2–3 hours of sleep per night, and that "[h]e did not appear to notice the marked difference between never getting to sleep once in 240 months, and getting fewer than the recommended number of hours each week."
  • Contradicted in more accurate reporting: Rhett Lamb of St. Petersburg, Florida, was initially reported to not sleep at all, but actually has a rare condition permitting him to sleep only one to two hours per day in the first three years of his life. He has a rare abnormality called an Arnold-Chiari malformation
    Arnold-Chiari malformation
    Arnold–Chiari malformation, or often simply Chiari malformation, is a malformation of the brain. It consists of a downward displacement of the cerebellar tonsils through the foramen magnum , sometimes causing non-communicating hydrocephalus as a result of obstruction of cerebrospinal fluid outflow...

     where brain tissue protrudes into the spinal canal; the skull puts pressure on the protruding part of the brain. The boy was operated on at All Children's Hospital in St. Petersburg in May 2008. Two days after surgery he slept through the night.

  • Pathological condition: French sleep expert Michel Jouvet
    Michel Jouvet
    Michel Valentin Marcel Jouvet is Emeritus Professor of Experimental Medicine at the University of Lyon. He spent one year in the laboratory of the Horace Magoun in Long Beach, California in 1955...

     and his team reported the case of a patient who was quasi-sleep-deprived for 4 months, as confirmed by repeated polygraphic recordings showing less than 30 min (of stage I sleep) per night, a condition they named "agrypnia". The 27-year-old man was suffering from Morvan's fibrillary chorea
    Morvan's syndrome
    Morvan’s Syndrome, or Morvan’s fibrillary chorea , is a rare autoimmune disease named after nineteenth century French physician Augustin Marie Morvan...

    , a rare disease that leads to involuntary movements, and in this particular case extreme insomnia. The researchers found that treatment with 5-HTP restored almost normal sleep stages, however some months after this recovery the patient died during a relapse which was unresponsive to 5-HTP. Despite the extreme insomnia, psychological investigation showed no sign of cognitive deficits, except for some hallucinations.

See also

  • Effects of sleep deprivation on cognitive performance
  • Narcolepsy
    Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...

  • Polyphasic sleep
    Polyphasic sleep
    Polyphasic sleep, a term coined by early 20th-century psychologist J.S. Szymanski, refers to the practice of sleeping multiple times in a 24-hour period—usually more than two, in contrast to biphasic sleep or monophasic sleep . It does not imply any particular sleep schedule...

  • Sleep debt
    Sleep debt
    Sleep debt or sleep deficit is the cumulative effect of not getting enough sleep. A large sleep debt may lead to mental and/or physical fatigue....

  • Sleep medicine
    Sleep medicine
    Sleep medicine is a medical specialty or subspecialty devoted to the diagnosis and therapy of sleep disturbances and disorders. From the middle of the 20th century, research has provided increasing knowledge and answered many questions about sleep-wake functioning. The rapidly evolving field has...

  • Sleep onset latency
    Sleep onset latency
    In sleep science, sleep onset latency is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages.-Sleep latency studies:...

  • Wake therapy
    Wake therapy
    Wake therapy is a form of sleep deprivation used as a treatment for depression. The subject is woken at 1AM and stays awake all morning, and the next full day. While sleepy, patients find that their depression vanishes, until they sleep again. Combining this with bright light therapy make the...

External links

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