Sleep Deprivation describes the cumulative effect of a person not having sufficient sleep. Insufficient sleep adversely effects the body, brain, mood and cognitive function. All aspects of health can be impacted by sleep deprivation.
Sleep deprivation is defined as not obtaining adequate total sleep. When someone is in a chronic sleep-restricted state they’ll notice excessive daytime sleepiness, fatigue, clumsiness, and weight gain or weight loss. In addition, being sleep-deprived affects both the brain and cognitive function.1
Interestingly, there’s a subset of cases whereby sleep deprivation can actually lead to an enhanced mood, alertness, and increased energy. Note that relatively few studies have compared the different effects between chronic partial-sleep restriction and acute total-sleep deprivation, and the total absence of sleep over long periods of time has not been studied in humans. That being said, long-term total sleep deprivation resulted in death in lab animals.
It’s now believed that people who experience short-term sleep restriction are not able to process glucose as efficiently as those who get eight hours of sleep; which means that they have an increased likelihood of developing Type 2 Diabetes. A study of more than 1400 participants conducted in 2005 showed that people who habitually slept for only a few hours were more prone to experience symptoms of Type 2 Diabetes.
In the year 2005, a study was conducted on a group of rats: for five days the rats were deprived of REM sleep and, compared to a group of rats which were not deprived of ‘dream’ sleep, the results showed no significant changes in their wound-healing ability. These rats were allowed NREM (deep) sleep.
We now know that sleep deprivation adversely affects the brain and cognitive function. A study completed by the VAHS in San Diego and the UCSD School of Medicine in the year 2000 monitored activity in the brains of sleep-deprived people whilst they performed basic verbal learning tasks by using functional magnetic resonance imaging (fMRI).
The results of the study showed that, in sleepier subjects, more activity was found in certain areas of the prefrontal cortex of the brain: The prefrontal cortex is an area of the brain that supports such mental faculties as logical and practical (‘means-ends’) reasoning and working memory. These results were interpreted by the researchers as indicating that, in order to complete a specific task, the average non-sleep-deprived subject’s brain needed to exert a lot more effort than the brain of an average non-sleep deprived person. They were able to infer from these results that the brains of sleep-deprived people were trying to compensate for the adverse effects created by sleep deprivation.
A survey conducted in 1999 revealed that sleep deprivation caused reduced cortisol secretion the following day - the result of increased slow-wave sleep. It was also revealed that, whilst suppressing growth hormones, sleep deprivation enhanced activity on the hypothalamus-pituitary-adrenal axis: this is the regulator of body functions such as the immune system, digestion, sex, mood, or energy usage; in addition to controlling reactions to stress. This study supports the findings of previous studies where adrenal insufficiency was observed in idiopathic hypersomnia.
Besides the many physical consequences of insufficient sleep, perhaps the most important consequences of sleep deprivation are deficits in working memory and attention. Lapses in ordinary mundane routines can cause worrying results; from missing words or sentences while taking notes to omitting important ingredients while cooking. It appears that carrying out tasks that require attention is in direct correlation to the number of hours the person sleeps each night; with these functions declining with the number hours of sleep deprivation. Methods such as choice-reaction time tasks are used to test working memory. Sadly, these attentional lapses can move into critical domains whereby the consequences could well result in life or death: industrial accidents and car crashes can be the result of inattentiveness, directly attributable to sleep deprivation.
Researchers typically use the (PVT) psychomotor vigilance task in order to measure the magnitude of attention deficits: this simply requires the patient to press a button at pseudo-random intervals in response to a light. An error is recorded when the patient fails to press the button in response to the light (stimulus), and this is noted as being attributable to the micro-sleeps occurring due to sleep deprivation.
When a patient has continuous muscular activity, but insufficient rest, we see other issues becoming more prevalent in sleep-deprived patients; such as cramping. Muscle fascia tears, hernias, and other problems usually associated with physical overexertion have been reported in extreme cases of sleep deprivation. At the extreme end of the scale, sleep deprivation can mimic psychosis, where distorted perceptions can lead to inappropriate behavioral and emotional responses.2
Interestingly, there have been studies that show sleep restriction might have potential when it comes to treating depression. We know that people suffering from depression experience earlier incidences of REM sleep plus increased rapid eye movements; and monitoring a patient’s EEG and waking them during bouts of REM sleep appears to produce a therapeutic effect, thus alleviating symptoms of depression. When sleep deprived, up to 60% of patients show signs of immediate recovery; however, most relapse the next night. It’s believed that this effect is linked to increases in the brain-derived neurotrophic factor (BDNF). It’s also been shown that, in normal people, chronotype is related to the effect that sleep deprivation has on mood: following sleep deprivation, people who prefer mornings become more depressed, while those who prefer evenings show a marked improvement in their mood.
In 2014, a thorough evaluation of the human metabolome in sleep deprivation discovered that 27 metabolites are increased following 24 waking hours, with suggestions that tryptophan, serotonin, and taurine may be contributing to the antidepressive effect.
When rats were exposed to prolonged sleep deprivation the result was that both food intake and energy expenditure increased, resulting in a net weight loss, and ultimately leading to death. The hypothesis of this study is that when moderate chronic sleep debt goes hand-in-hand with habitual short sleep, energy expenditure and increased appetite are encouraged; and, in societies where high-calorie food is freely available the equation is tipped towards food intake rather than expenditure. Nationally representative samples used in several large studies suggest that one of the causes of the United States obesity problem could possibly be due to the corresponding decrease in the average number of hours that people sleep.
These findings indicate that the hormones that regulate appetite and glucose metabolism could be disrupted because of sleep deprivation. It appears that the association between obesity and sleep deprivation is strongest in young and middle-age adults. On the other hand, there are scientists who believe that related problems, such as sleep apnea, together with the physical discomfort of obesity, reduce a person’s likelihood of getting a good night’s sleep.
Sleep disorders that reduce sleep time like insomnia, sleep apnea, RLS, and others.
The primary treatment of sleep deprivation is to increase total sleep time. Treating the cause of sleep deprivation is generally the solution to the problem. If a sleep disorder is interrupting sleep, the problem will need to be addressed in order to improve sleep duration and quality. Inadequate sleep hygiene or insufficient sleep is often a cause that needs to be addressed.3
In 1965, Randy Gardner stayed awake for 11 days as part of an experiment.
If you are struggling with sleep deprivation symptoms, talk to your physician or sleep doctor about treatment options.
© 2020 American Sleep Association.