thesis about the importance of sleep

Why sleep is important

Sleep is essential for a person’s health and wellbeing, according to the National Sleep Foundation (NSF). Yet millions of people do not get enough sleep and many suffer from lack of sleep. For example, surveys conducted by the NSF (1999-2004) reveal that at least 40 million Americans suffer from over 70 different sleep disorders and 60 percent of adults report having sleep problems a few nights a week or more. Most of those with these problems go undiagnosed and untreated. In addition, more than 40 percent of adults experience daytime sleepiness severe enough to interfere with their daily activities at least a few days each month — with 20 percent reporting problem sleepiness a few days a week or more. Furthermore, 69 percent of children experience one or more sleep problems a few nights or more during a week.

According to psychologist and sleep expert David F. Dinges, Ph.D., of the Division of Sleep and Chronobiology and Department of Psychiatry at the University of Pennsylvania School of Medicine, irritability, moodiness and disinhibition are some of the first signs a person experiences from lack of sleep . If a sleep-deprived person doesn’t sleep after the initial signs, said Dinges, the person may then start to experience apathy, slowed speech and flattened emotional responses, impaired memory and an inability to be novel or multitask. As a person gets to the point of falling asleep, he or she will fall into micro sleeps (5-10 seconds) that cause lapses in attention, nod off while doing an activity like driving or reading and then finally experience hypnagogic hallucinations, the beginning of REM sleep. (Dinges, Sleep, Sleepiness and Performance , 1991)

Everyone’s individual sleep needs vary. In general, most healthy adults are built for 16 hours of wakefulness and need an average of eight hours of sleep a night. However, some individuals are able to function without sleepiness or drowsiness after as little as six hours of sleep. Others can't perform at their peak unless they've slept ten hours. And, contrary to common myth, the need for sleep doesn't decline with age but the ability to sleep for six to eight hours at one time may be reduced. (Van Dongen & Dinges, Principles & Practice of Sleep Medicine , 2000)

Psychologists and other scientists who study the causes of sleep disorders have shown that such problems can directly or indirectly be tied to abnormalities in the following systems:

Physiological systems

Brain and nervous system

Cardiovascular system

Metabolic functions

Immune system

Furthermore, unhealthy conditions, disorders and diseases can also cause sleep problems, including:

Pathological sleepiness, insomnia and accidents

Hypertension and elevated cardiovascular risks (MI, stroke)

Emotional disorders (depression, bipolar disorder)

Obesity; metabolic syndrome and diabetes

Alcohol and drug abuse (Dinges, 2004)

Groups that are at particular risk for sleep deprivation include night shift workers, physicians (average sleep = 6.5 hours a day; residents = 5 hours a day), truck drivers, parents and teenagers. (American Academy of Sleep Medicine and National Heart, Lung, and Blood Institute Working Group on Problem Sleepiness. 1997).

Stress is the number one cause of short-term sleeping difficulties , according to sleep experts. Common triggers include school- or job-related pressures, a family or marriage problem and a serious illness or death in the family. Usually the sleep problem disappears when the stressful situation passes. However, if short-term sleep problems such as insomnia aren't managed properly from the beginning, they can persist long after the original stress has passed.

Drinking alcohol or beverages containing caffeine in the afternoon or evening, exercising close to bedtime, following an irregular morning and nighttime schedule, and working or doing other mentally intense activities right before or after getting into bed can disrupt sleep.

If you are among the 20 percent of employees in the United States who are shift workers, sleep may be particularly elusive. Shift work forces you to try to sleep when activities around you — and your own "biological rhythms" — signal you to be awake. One study shows that shift workers are two to five times more likely than employees with regular, daytime hours to fall asleep on the job.

Traveling also disrupts sleep, especially jet lag and traveling across several time zones. This can upset your biological or “circadian” rhythms.

Environmental factors such as a room that's too hot or cold, too noisy or too brightly lit can be a barrier to sound sleep. And interruptions from children or other family members can also disrupt sleep. Other influences to pay attention to are the comfort and size of your bed and the habits of your sleep partner. If you have to lie beside someone who has different sleep preferences, snores, can't fall or stay asleep, or has other sleep difficulties, it often becomes your problem too!

Having a 24/7 lifestyle can also interrupt regular sleep patterns: the global economy that includes round the clock industries working to beat the competition; widespread use of nonstop automated systems to communicate and an increase in shift work makes for sleeping at regular times difficult.

A number of physical problems can interfere with your ability to fall or stay asleep. For example, arthritis and other conditions that cause pain, backache, or discomfort can make it difficult to sleep well.

Epidemiological studies suggest self-reported sleep complaints are associated with an increased relative risk of cardiovascular morbidity and mortality. For women, pregnancy and hormonal shifts including those that cause premenstrual syndrome (PMS) or menopause and its accompanying hot flashes can also intrude on sleep.

Finally, certain medications such as decongestants, steroids and some medicines for high blood pressure, asthma, or depression can cause sleeping difficulties as a side effect.

It is a good idea to talk to a physician or mental health provider about any sleeping problem that recurs or persists for longer than a few weeks.

According to the DSM, some psychiatric disorders have fatigue as a major symptom. Included are: major depressive disorder (includes postpartum blues), minor depression , dysthymia, mixed anxiety-depression, seasonal affective disorder and bipolar disorder .

According to a long-term study published in the 2004 April issue of Alcoholism: Clinical and Experimental Research , young teenagers whose preschool sleep habits were poor were more than twice as likely to use drugs, tobacco or alcohol. This finding was made by the University of Michigan Health System as part of a family health study that followed 257 boys and their parents for 10 years. The study found a significant connection between sleep problems in children and later drug use, even when other issues such as depression, aggression, attention problems and parental alcoholism were taken into account. Long-term data on girls isn't available yet. The researchers suggest that early sleep problems may be a "marker" for predicting later risk of early adolescent substance abuse — and that there may be a common biological factor underlying both traits. Although the relationship between sleep problems and the abuse of alcohol in adults is well known, this is the first study to look at the issue in children.

Nightmares are dreams with vivid and disturbing content. They are common in children during REM sleep. They usually involve an immediate awakening and good recall of the dream content.

Sleep terrors are often described as extreme nightmares. Like nightmares, they most often occur during childhood, however they typically take place during non-REM (NREM) sleep. Characteristics of a sleep terror include arousal, agitation, large pupils, sweating, and increased blood pressure. The child appears terrified, screams and is usually inconsolable for several minutes, after which he or she relaxes and returns to sleep. Sleep terrors usually take place early in the night and may be combined with sleepwalking. The child typically does not remember or has only a vague memory of the terrifying events.

In the August 2004 issue of the journal Sleep , Dr. Timothy Roehrs, the Director of research at the Sleep Disorders and Research Center at Henry Ford Hospital in Detroit published one of the first studies to measure the effect of sleepiness on decision making and risk taking. He found that sleepiness does take a toll on effective decision making.

Cited in the October 12, New York Times Science section, Dr. Roehrs and his colleagues paid sleepy and fully alert subjects to complete a series of computer tasks. At random times, they were given a choice to take their money and stop. Or they could forge ahead with the potential of either earning more money or losing it all if their work was not completed within an unknown remainder of time.

Dr. Roehrs found that the alert people were very sensitive to the amount of work they needed to do to finish the tasks and understood the risk of losing their money if they didn't. But the sleepy subjects chose to quit the tasks prematurely or they risked losing everything by trying to finish the task for more money even when it was 100 percent likely that they would be unable to finish, said Dr. Roehrs.

According to the National Commission on Sleep Disorders Research (1998) and reports from the National Highway Safety Administration (NHSA)(2002), high-profile accidents can partly be attributed to people suffering from a severe lack of sleep.

Each year the cost of sleep disorders, sleep deprivation and sleepiness, according to the NCSDR, is estimated to be $15.9 million in direct costs and $50 to $100 billion a year in indirect and related costs. And according to the NHSA, falling asleep while driving is responsible for at least 100,000 crashes, 71,000 injuries and 1,550 deaths each year in the United States. Young people in their teens and twenties, who are particularly susceptible to the effects of chronic sleep loss, are involved in more than half of the fall-asleep crashes on the nation's highways each year. Sleep loss also interferes with the learning of young people in our nation's schools, with 60 percent of grade school and high school children reporting that they are tired during the daytime and 15 percent of them admitting to falling asleep in class.

According to the Department of Transportation (DOT), one to four percent of all highway crashes are due to sleepiness, especially in rural areas and four percent of these crashes are fatal.

Risk factors for drowsy driving crashes:

Late night/early morning driving

Patients with untreated excessive sleepiness

People who obtain six or fewer hours of sleep per day

Young adult males

Commercial truck drivers

Night shift workers

Medical residents after their shift

According to sleep researchers, a night's sleep is divided into five continually shifting stages, defined by types of brain waves that reflect either lighter or deeper sleep. Toward morning, there is an increase in rapid eye movement, or REM sleep, when the muscles are relaxed and dreaming occurs, and recent memories may be consolidated in the brain. The experts say that hitting a snooze alarm over and over again to wake up is not the best way to feel rested. “The restorative value of rest is diminished, especially when the increments are short,” said psychologist Edward Stepanski, PhD who has studied sleep fragmentation at the Rush University Medical Center in Chicago. This on and off again effect of dozing and waking causes shifts in the brain-wave patterns. Sleep-deprived snooze-button addicts are likely to shorten their quota of REM sleep, impairing their mental functioning during the day. ( New York Times , October 12, 2004)

Certain therapies, like cognitive behavioral therapy teach people how to recognize and change patterns of thought and behavior to solve their problems. Recently this type of therapy has been shown to be very effective in getting people to fall asleep and conquer insomnia.

According to a study published in the October 2004 issue of The Archives of Internal Medicine , cognitive behavior therapy is more effective and lasts longer than a widely used sleeping pill, Ambien, in reducing insomnia. The study involved 63 healthy people with insomnia who were randomly assigned to receive Ambien, the cognitive behavior therapy, both or a placebo. The patients in the therapy group received five 30-minute sessions over six weeks. They were given daily exercises to “recognize, challenge and change stress-inducing” thoughts and were taught techniques, like delaying bedtime or getting up to read if they were unable to fall asleep after 20 minutes. The patients taking Ambien were on a full dose for a month and then were weaned off the drug. At three weeks, 44 percent of the patients receiving the therapy and those receiving the combination therapy and pills fell asleep faster compared to 29 percent of the patients taking only the sleeping pills. Two weeks after all the treatment was over, the patients receiving the therapy fell asleep in half the time it took before the study and only 17 percent of the patients taking the sleeping pills fell asleep in half the time. (New York Times, October 5, 2004)

According to leading sleep researchers, there are techniques to combat common sleep problems:

Keep a regular sleep/wake schedule

Don’t drink or eat caffeine four to six hours before bed and minimize daytime use

Don’t smoke, especially near bedtime or if you awake in the night

Avoid alcohol and heavy meals before sleep

Get regular exercise

Minimize noise, light and excessive hot and cold temperatures where you sleep

Develop a regular bed time and go to bed at the same time each night

Try and wake up without an alarm clock

Attempt to go to bed earlier every night for certain period; this will ensure that you’re getting enough sleep

In clinical settings, cognitive-behavior therapy (CBT) has a 70-80 percent success rate for helping those who suffer from chronic insomnia. Almost one third of people with insomnia achieve normal sleep and most reduce their symptoms by 50 percent and sleep an extra 45-60 minutes a night. When insomnia exists along with other psychological disorders like depression, say the experts, the initial treatment should address the underlying condition.

But sometimes even after resolving the underlying condition, the insomnia still exists, says psychologist Jack Edinger, PhD, of the VA Medical Center in Durham, North Carolina and Professor of Psychiatry and Behavioral Sciences at Duke University and cautions that treating the depression usually doesn’t resolve the sleep difficulties. From his clinical experience, he has found that most patients with insomnia should be examined for specific behaviors and thoughts that may perpetuate the sleep problems. When people develop insomnia, they try to compensate by engaging in activities to help them get more sleep. They sleep later in the mornings or spend excessive times in bed. These efforts usually backfire, said Edinger.

From his clinical work and research on sleep, psychologist Charles M. Morin, PhD, a Professor in the Psychology Department and Director of the Sleep Disorders Center at University Laval in Quebec, Canada says that ten percent of adults suffer from chronic insomnia. In a study released in the recent issue of Sleep Medicine Alert published by the NSF, Morin outlines how CBT helps people overcome insomnia. Clinicians use sleep diaries to get an accurate picture of someone’s sleep patterns. Bedtime, waking time, time to fall asleep, number and durations of awakening, actual sleep time and quality of sleep are documented by the person suffering from insomnia.

A person can develop poor sleep habits (i.e. watching TV in bed or eating too much before bedtime), irregular sleep patterns (sleeping too late, taking long naps during the day) to compensate for lost sleep at night. Some patients also develop a fear of not sleeping and a pattern of worrying about the consequences of not sleeping, said Morin. “Treatments that address the poor sleep habits and the faulty beliefs and attitudes about sleep work but sometimes,” said Morin, “medication may play a role in breaking the cycle of insomnia. But behavioral therapies are essential for patients to alter the conditions that perpetuate it.”

CBT attempts to change a patient’s dysfunctional beliefs and attitudes about sleep. “It restructure thoughts — like, ‘I’ve got to sleep eight hours tonight’ or ‘I’ve got to take medication to sleep’ or ‘I just can’t function or I’ll get sick if I don’t sleep.’ These thoughts focus too much on sleep, which can become something like performance anxiety — sleep will come around to you when you’re not chasing it,” said Edinger.

What works in many cases, said Morin and Edinger, is to standardize or restrict a person’s sleep to give a person more control over his or her sleep. A person can keep a sleep diary for a couple of weeks and a clinician can monitor the amount of time spent in bed to the actual amount of time sleeping. Then the clinician can instruct the patient to either go to bed later and get up earlier or visa versa. This procedure improves the length of sleeping time by imposing a mild sleep deprivation situation, which has the result of reducing the anxiety surrounding sleep. To keep from falling asleep during the day, patients are told not to restrict sleep to less than five hours.

Standardizing sleep actually helps a person adjust his or her homeostatic mechanism that balances sleep, said Edinger. “Therefore, if you lose sleep, your homeostatic mechanism will kick in and will work to increase the likelihood of sleeping longer and deeper to promote sleep recovery. This helps a person come back to their baseline and works for the majority.”

A person can also establish more stimulus control over his or her bedroom environment, said Morin. This could include: going to bed only when sleepy, getting out of bed when unable to sleep, prohibiting non-sleep activities in the bedroom, getting up at the same time every morning (including weekends) and avoiding daytime naps.

Finally, a person can incorporate relaxation techniques as part of his or her treatment. For example, a person can give herself or himself an extra hour before bed to relax and unwind and time to write down worries and plans for the following day.

In CBT, said Morin, breaking the thought process and anxiety over sleep is the goal. “After identifying the dysfunctional thought patterns, a clinician can offer alternative interpretations of what is getting the person anxious so a person can think about his or her insomnia in a different way.” Morin offers some techniques to restructure a person’s cognitions. “Keep realistic expectations, don’t blame insomnia for all daytime impairments, do not feel that losing a night’s sleep will bring horrible consequences, do not give too much importance to sleep and finally develop some tolerance to the effects of lost sleep.

According to Edinger, aging weakens a person’s homeostatic sleep drive after age 50. Interestingly, the length of the circadian cycle stays roughly the same over the lifespan but the amplitude of the circadian rhythm may decline somewhat with aging.

National Sleep Foundation http://www.thensf.org

American Academy of Sleep Medicine http://www.aasmnet.org/

American Insomnia Association http://www.americaninsomniaassociation.org/

Sleep Research Society http://www.sleepresearchsociety.org/

NIH National Center for Sleep Disorders Research http://www.nhlbi.nih.gov/sleep

The MayoClinic.com Sleep Center

(Blake, et al, Psychological Reports, 1998; National Heart, Lung and Blood Institute Working Group on Insomnia, 1998)

David F. Dinges, PhD , Professor of Psychology in Psychiatry, Chief, Division of Sleep and Chronobiology, University of Pennsylvania School of Medicine

Jack Edinger, PhD , of the VA Medical Center in Durham, North Carolina and Professor of Psychiatry and Behavioral Sciences at Duke University

Charles M. Morin, PhD , a Professor in the Psychology Department and Director of the Sleep Disorders Center at University Laval in Quebec, Canada

Timothy Roehrs, PhD , the Director of Research, Sleep Disorders and Research Center at Henry Ford Hospital

Edward Stepanski, PhD , who has studied sleep fragmentation at the Rush University Medical Center in Chicago

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Why a Good Night’s Sleep Is Important for Your Health

• Restoration
• Stress Reduction
• Body Weight
• Illness Prevention
• Mental Health

How to Improve Your Sleep

Sleep is important due to the impact it has on your overall health. Appropriate sleep is needed for mental focus and memory, managing stress, maintaining proper body weight, boosting the immune system, and a host of other wellness needs. Some studies suggest sleep can help to prevent illness, such as diabetes or obesity .

Adults aged 18 to 60 years should get at least seven hours of sleep each night in order to achieve the benefits of sleep. If not, you run the risk of becoming sleep-deprived .

This article explains the role of sleep in overall health and offers tips on how to improve your sleep. Research on sleep and sleep cycles has elevated awareness about sleep hygiene (healthy sleep habits) and the quality of sleep.

 Illustration by Emily Roberts for Verywell Health

Sleep Is Restorative

When you sleep, you allow your body to repair and rebuild. During this time, the body is able to clear debris from the lymphatic system, which boosts the immune system.

While you sleep, there are many important processes that happen, including:

• Muscle repair
• Protein synthesis
• Tissue growth
• Hormone release

Sleep Reduces Stress

Sleep is a powerful stress reliever. It improves concentration, regulates mood, and sharpens judgment and decision-making. A lack of sleep not only reduces mental clarity but the ability to cope with stressful situations.

This is due, in part, to changes in cortisol levels. Typically, your cortisol levels fall in the evening hours, as one element of the body’s natural preparation for sleep. When sleep is lost, cortisol levels remain high and interfere with the release of melatonin, a hormone that is essential for the regulation of sleep-wake cycles.

Some studies suggest these changes could even be used to evaluate depression in people with bipolar disorder. Other studies demonstrate a link between sleep, chronic stress, and depression with an eye on heart rate changes.

Sleep Improves Your Memory

The link between sleep and memory processing is well established. Sleep serves as an opportunity for the mind to process all the stimuli taken in while awake. It triggers changes in the brain that strengthen neural connections helping us to form memories.

Sleep quality is important when learning new information and using memory. Numerous research studies find that electrophysiological, neurochemical, and genetic mechanisms that take place during the slow-wave sleep stage of sleep are key.

Sleep Helps You Maintain a Healthy Body Weight

When you are sleep deprived, your body alters the hormones that regulate hunger and appetite. These hormones include:

• Leptin: This hormone suppresses appetite and encourages the body to expend energy.
• Ghrelin: This hormone triggers feelings of hunger.

Both of these hormones are thrown off when you are short on sleep—leptin goes down and ghrelin goes up. Obstructive sleep apnea , a serious sleep disorder, is linked with obesity as well.

Sleep and Appetite

Sleep deprivation can activate the endocannabinoid (eCB) system in the brain (the same areas activated by marijuana) which increases hunger and appetite. Stimulating the eCB reward system makes you more likely to crave junk food.  You are also more likely to make these unhealthy lifestyle choices when you are tired. If that's often the case, it can lead to weight gain or diabetes over time.  

Sleep May Prevent Illnesses

Sleep deprivation can have very detrimental health impacts and has been linked to chronic diseases such as diabetes and heart disease. Here are some of the health conditions in which it may play a role.

Respiratory Illness and Infection

Lack of sleep makes you more vulnerable to respiratory illness and infection. A study of more than 600,000 people found that insomnia was a contributing cause when catching a cold or the flu , as well as a factor in how severe the infection became.

Obstructive sleep apnea, a common sleep disturbance, is linked with a number of cardiovascular (heart and blood vessel) diseases. For example, 40% to 60% of people experiencing symptomatic heart failure also are diagnosed with sleep-disordered breathing.

Other heart conditions linked with sleep apnea include:

• Coronary artery disease
• Pulmonary hypertension
• High blood pressure
• Heart arrhythmias

There's no direct evidence to suggest that sleep quantity or quality affects the risk of cancer, although studies have looked at the role of sleep in developing breast cancer , lung cancer , and more.

For example, research on lung cancer suggests a relationship between lack of sleep and adenocarcinoma risk, but more research on sleep traits (how long you sleep, whether you take naps) is needed.

Studies also are exploring the role of sleep in those already diagnosed with cancer, especially because difficulty sleeping affects up to 95% of people receiving cancer treatment and care. Sleep deprivation may affect the body's ability to fight cancer and lead to a poor prognosis, which was the conclusion of researchers focused on liver cancer .

A number of studies have shown that sleep deprivation leads to reduced glucose tolerance and impaired insulin sensitivity in humans. Additional studies suggest the risk of type 2 diabetes rises due to inadequate sleep, with seven or eight hours considered the optimal amount.

Researchers also think the timing of sleep may have impacts, too. Disruptions in circadian rhythm, with many people working at night or otherwise "living against the clock" of natural sleep cycles, also have impacts. Sleep disruption appears to affect metabolism and related diseases.

Neurodegenerative Disease

Sleep plays a key role in how your body produces cerebrospinal fluid (CSF), what it's composed of, and how the CSF is distributed in your brain and spinal cord. A number of studies have looked at how components in CSF, like amyloid-beta levels, might be linked to Alzheimer's disease and other neurodegenerative disorders.

The research results are mixed, but there is evidence to suggest that sleep patterns affect levels of amyloid-beta, orexin, tau proteins, interleukin 8 (IL-8), and other components. This may influence the development of Lewy body dementia, Parkinson's, or Alzheimer's disease, or it may contribute to sleep disruptions that are common in people living with these disorders.

Researchers also are investigating the role of CSF, sleep, and the early development of autism .

Sleep Is Important for Your Mental Health

Evidence suggests lack of sleep contributes to the formation of new mental health problems and to the maintenance of existing ones, but the magnitude of its effect is difficult to estimate and may be different across mental health conditions.

Sleep problems are very common in those with mental illness. In fact, disrupted sleep is commonly seen as both a symptom and consequence of mental health disorders, although sleep deprivation is rarely treated as the cause of mental health conditions.

The most common sleep problem associated with poor mental health is insomnia, with symptoms of:

• Not feeling well-rested after a night's sleep
• Daytime tiredness or sleepiness
• Irritability, depression, or anxiety
• Difficulty paying attention, focusing on tasks, or remembering
• Increased errors or accidents
• Ongoing worries about sleep

You may experience insomnia for a number of reasons, but the most common culprits are: 

• Work schedule
• Poor sleep habits
• Excessive alcohol or caffeine use at night 
• Habitual nighttime screen use

Illustration by JR Bee for Verywell Health

Small changes to your nighttime routine can result in a huge health benefit:

• Establish a realistic bedtime and stick to it every night, even on the weekends.
• Maintain comfortable temperature settings and low light levels in your bedroom.
• Consider a “screen ban” on televisions, computers and tablets, cell phones, and other electronic devices in your bedroom.
• Abstain from caffeine, alcohol, and large meals in the hours leading up to bedtime.
• Refrain from using tobacco at any time of day or night.
• Exercise during the day; this can help you wind down in the evening and prepare for sleep.

Sleep is vital to maintaining health, and most adults need seven or more hours each day. There is increasing evidence that adequate, high-quality sleep can help prevent illnesses like respiratory infection as well as limit the risk of diabetes, heart disease, and other serious conditions.

Memory, mood, and mental health also are affected by sleep deprivation and other sleep disorders.

There are lifestyle steps you can take to improve sleep. Talk to your healthcare provider if you have concerns or questions about how sleep patterns are affecting your health.

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Chong PLH, Garic D, Shen MD, Lundgaard I, Schwichtenberg AJ. Sleep, cerebrospinal fluid, and the glymphatic system: A systematic review . Sleep Med Rev . 2022 Feb;61:101572. doi:10.1016/j.smrv.2021.101572. 

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da Estrela C, McGrath J, Booij L, Gouin JP. Heart Rate Variability, Sleep Quality, and Depression in the Context of Chronic Stress . Ann Behav Med . 2021 Mar 16;55(2):155-164. doi:10.1093/abm/kaaa039.

Tucker MA, Humiston GB, Summer T, Wamsley E. Comparing the effects of sleep and rest on memory consolidation . Nature and Science of Sleep . 2020 Feb 3;12:79-91. doi:10.2147/NSS.S223917

Rasch B, Born J. About sleep’s role in memory .  Physiological Reviews . 2013;93(2):681-766. doi: 10.1152/physrev.00032.2012 

Chaput JP, McHill AW, Cox RC, Broussard JL, Dutil C, da Costa BGG, Sampasa-Kanyinga H, Wright KP Jr. The role of insufficient sleep and circadian misalignment in obesity . Nat Rev Endocrinol . 2023 Feb;19(2):82-97. doi:10.1038/s41574-022-00747-7.

Yeghiazarians Y, Jneid H, Tietjens JR, Redline S, Brown DL, El-Sherif N, et al . Obstructive Sleep Apnea and Cardiovascular Disease: A Scientific Statement From the American Heart Association . Circulation . 2021 Jul 20;144(3):e56-e67. doi:10.1161/CIR.0000000000000988.

Hanlon EC, Tasali E, Leproult R, Stuhr KL, Doncheck E, de Wit H, Hillard CJ, Van Cauter E.  Sleep restriction enhances the daily rhythm of circulating levels of endocannabinoid 2-arachidonoylglycerol . 2016 Mar 1;39(3):653-64. doi:10.5665/sleep.5546

Jones SE, Maisha FI, Strausz SJ, Lammi V, Cade BE, Tervi A, et al . The public health impact of poor sleep on severe COVID-19, influenza and upper respiratory infections . EBioMedicine . 2023 Jul;93:104630. doi:10.1016/j.ebiom.2023.104630

Wang J, Tang H, Duan Y, Yang S, An J. Association between Sleep Traits and Lung Cancer: A Mendelian Randomization Study . J Immunol Res . 2021 Jun 21;2021:1893882. doi:10.1155/2021/1893882. 

Büttner-Teleagă A, Kim YT, Osel T, Richter K. Sleep Disorders in Cancer-A Systematic Review . Int J Environ Res Public Health . 2021 Nov 7;18(21):11696. doi:10.3390/ijerph182111696.

Huang J, Song P, Hang K, Chen Z, Zhu Z, Zhang Y, et al . Sleep Deprivation Disturbs Immune Surveillance and Promotes the Progression of Hepatocellular Carcinoma . Front Immunol . 2021 Sep 3;12:727959. doi:10.3389/fimmu.2021.727959.

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By Shamard Charles, MD, MPH Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.

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Good Sleep for Good Health

Get the Rest You Need

Sometimes, the pace of modern life barely gives you time to stop and rest. It can make getting a good night’s sleep on a regular basis seem like a dream.

But sleep is as important for good health as diet and exercise. Good sleep improves your brain performance, mood, and health.

Not getting enough quality sleep regularly raises the risk of many diseases and disorders. These range from heart disease and stroke to obesity and dementia.

There’s more to good sleep than just the hours spent in bed, says Dr. Marishka Brown, a sleep expert at NIH. “Healthy sleep encompasses three major things,” she explains. “One is how much sleep you get. Another is sleep quality—that you get uninterrupted and refreshing sleep. The last is a consistent sleep schedule.”

People who work the night shift or irregular schedules may find getting quality sleep extra challenging. And times of great stress—like the current pandemic—can disrupt our normal sleep routines. But there are many things you can do to improve your sleep.

Sleep for Repair

Why do we need to sleep? People often think that sleep is just “down time,” when a tired brain gets to rest, says Dr. Maiken Nedergaard, who studies sleep at the University of Rochester.

“But that’s wrong,” she says. While you sleep, your brain is working. For example, sleep helps prepare your brain to learn, remember, and create.

Nedergaard and her colleagues discovered that the brain has a drainage system that removes toxins during sleep.

“When we sleep, the brain totally changes function,” she explains. “It becomes almost like a kidney, removing waste from the system.”

Her team found in mice that the drainage system removes some of the proteins linked with Alzheimer’s disease. These toxins were removed twice as fast from the brain during sleep.

Everything from blood vessels to the The system that protects your body from invading viruses, bacteria, and other microscopic threats. immune system uses sleep as a time for repair, says Dr. Kenneth Wright, Jr., a sleep researcher at the University of Colorado.

“There are certain repair processes that occur in the body mostly, or most effectively, during sleep,” he explains. “If you don’t get enough sleep, those processes are going to be disturbed.”

Sleep Myths and Truths

How much sleep you need changes with age. Experts recommend school-age children get at least nine hours a night and teens get between eight and 10. Most adults need at least seven hours or more of sleep each night.

There are many misunderstandings about sleep. One is that adults need less sleep as they get older. This isn’t true. Older adults still need the same amount. But sleep quality can get worse as you age. Older adults are also more likely to take medications that interfere with sleep.

Another sleep myth is that you can “catch up” on your days off. Researchers are finding that this largely isn’t the case.

“If you have one bad night’s sleep and take a nap, or sleep longer the next night, that can benefit you,” says Wright. “But if you have a week’s worth of getting too little sleep, the weekend isn’t sufficient for you to catch up. That’s not a healthy behavior.”

In a recent study, Wright and his team looked at people with consistently deficient sleep. They compared them to sleep-deprived people who got to sleep in on the weekend.

Both groups of people gained weight with lack of sleep. Their bodies’ ability to control blood sugar levels also got worse. The weekend catch-up sleep didn’t help.

On the flip side, more sleep isn’t always better, says Brown. For adults, “if you’re sleeping more than nine hours a night and you still don’t feel refreshed, there may be some underlying medical issue,” she explains.

Sleep Disorders

Some people have conditions that prevent them from getting enough quality sleep, no matter how hard they try. These problems are called sleep disorders.

The most common sleep disorder is insomnia. “Insomnia is when you have repeated difficulty getting to sleep and/or staying asleep,” says Brown. This happens despite having the time to sleep and a proper sleep environment. It can make you feel tired or unrested during the day.

Insomnia can be short-term, where people struggle to sleep for a few weeks or months. “Quite a few more people have been experiencing this during the pandemic,” Brown says. Long-term insomnia lasts for three months or longer.

Sleep apnea is another common sleep disorder. In sleep apnea, the upper airway becomes blocked during sleep. This reduces or stops airflow, which wakes people up during the night. The condition can be dangerous. If untreated, it may lead to other health problems.

If you regularly have problems sleeping, talk with your health care provider. They may have you keep a sleep diary to track your sleep for several weeks. They can also run tests, including sleep studies. These look for sleep disorders.

Getting Better Sleep

If you’re having trouble sleeping, hearing how important it is may be frustrating. But simple things can improve your odds of a good night’s sleep. See the Wise Choices box for tips to sleep better every day.

Treatments are available for many common sleep disorders. Cognitive behavioral therapy can help many people with insomnia get better sleep. Medications can also help some people.

Many people with sleep apnea benefit from using a device called a CPAP machine. These machines keep the airway open so that you can breathe. Other treatments can include special mouthguards and lifestyle changes.

For everyone, “as best you can, try to make sleep a priority,” Brown says. “Sleep is not a throwaway thing—it’s a biological necessity.”

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Why Do We Need Sleep?

Contributing Writer

Lucy Bryan is a writer and editor with more than a decade of experience in higher education. She holds a B. A. in journalism from the University of North Carolina at Chapel Hill and an M.F.A. in creative writing from Penn State University.

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Brandon R. Peters, M.D., FAASM, is a double board-certified neurologist and sleep medicine specialist and fellow of the American Academy of Sleep Medicine who currently practices at Virginia Mason Franciscan Health in Seattle. He is a leading voice in sleep medicine who works at the cutting edge of medicine and technology to advance the field.

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Table of Contents

Why Getting Enough Sleep Is Important

The science behind why we sleep, how much sleep do i need, the effects of a lack of sleep, how to always get a good night’s sleep.

If you’ve stayed awake all night—by choice, out of necessity, or in spite of your efforts to sleep—you know just how critical sleep is to your wellbeing. Everyone needs sleep, but about one in three American adults don’t get enough of it.

The consequences of sleep deprivation are serious, so it’s worth learning why sleep matters, how it works, and how to give yourself the best chances of getting a good night’s sleep.

Sleep is an essential function that allows your body and mind to recharge, leaving you refreshed and alert when you wake up. Healthy sleep also helps the body remain healthy and stave off diseases. Without enough sleep, the brain cannot function properly, impairing your abilities to concentrate, think clearly, and process memories.

Sleep serves a variety of important physical and psychological functions, including:  

• Learning and memory consolidation: Sleep helps with focus and concentration—and it allows the brain to register and organize memories —all of which are vital to learning.
• Emotional regulation: Sleep helps people regulate their emotions Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source and better manage the physical and psychological effects of stress.
• Judgment and decision making: Sleep influences a person’s ability to recognize danger and threats. Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source Healthy sleep supports sound judgment, good decision making, and other executive functions.
• Problem solving: Research shows that “sleeping on” a complex problem improves a person’s chance of solving it. Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source
• Energy conservation: Sleep allows people to conserve energy through an extended period of reduced activity.
• Growth and healing: Sleep provides the release of growth hormone necessary for the body’s tissues to grow and repair damage.
• Immunity: Sleep supports immune function , allowing the body to fight off diseases and infections.

Human beings, like all species on Earth, evolved to survive and thrive on a planet with a 24-hour cycle of day and night. According to some theories of sleep, Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source sleeping in one consolidated block at night allowed early humans to simultaneously avoid predators, conserve energy, and meet their need for rest. It also kept them from having to adapt to life in two very different conditions—daylight and darkness.

The biological patterns that help humans live according to the 24-hour day-night cycle are called circadian rhythms . These rhythms work alongside the sleep drive —a desire to sleep that grows in intensity the longer a person has been awake—to cause people to feel sleepy at night and alert in the morning. 

Circadian rhythms, including the sleep-wake cycle, operate according to environmental cues. Every evening, as darkness sets in, the body begins releasing the sleep hormone melatonin—and every morning, with the arrival of light , the body’s melatonin levels become undetectable. An evening drop and morning rise in body temperature accompanies this cycle, enhancing sleepiness and alertness at the right times.

Stages of Sleep

Our sleep architecture—that is, the way the body cycles through specific stages of sleep —enables the beneficial processes that occur during sleep, such as healing and learning. There are three non-rapid eye movement (non-REM) stages of sleep followed by rapid eye movement (REM), the final stage of sleep. Experiencing all four usually takes anywhere from 1.5 to 2 hours. Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source

• Stage N1: This is the lightest stage of sleep, and it usually only lasts a few minutes.
• Stage N2: Healthy adults usually spend about half of the night in N2 sleep. While brain activity slows, there are bursts of activity that may help with memory retention and learning.
• Stage N3: N3 sleep, also called “slow wave sleep” or “deep sleep,” helps a person wake up feeling refreshed. During this stage, blood pressure lowers, heart rate and breathing rate slow, and the body secretes growth hormone. People generally spend about 10% to 20% of the night in this stage. 
• REM Sleep: As its name suggests, people’s eyes intermittently move rapidly during this sleep stage. Most vivid dreaming takes place during REM sleep, and skeletal muscles become temporarily paralyzed to prevent a person from acting out their dreams. Memory consolidation occurs in this stage. It accounts for 20% to 25% of a typical night of sleep, with more of it occurring towards morning.

Healthy individuals cycle through all four stages of sleep multiple times a night. Regular sleep disruptions, as well as sleep disorders that affect sleep architecture like sleep apnea, can have serious consequences for physical health and mental health .

Experts generally recommend that adults get at least seven hours of sleep per night. Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source However, sleep needs can vary dramatically from person to person. Your activity level, your health status, and many other factors influence how much sleep you need , but the optimal number of hours typically falls within a specific range depending on your age and stage in life.

Not getting the amount of sleep your body needs can have serious consequences. Just one sleepless night can make it harder for you to focus and think clearly, and you might feel tired or sluggish during the day. You’re more likely to feel irritable and to exercise poor judgment when you haven’t had enough sleep. And sleep deprivation significantly elevates your risk Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source of making a mistake at work or having a car accident.

Long-term sleep deprivation carries all these risks and more. Chronic insufficient sleep may:

• Suppress your immune system, increasing your susceptibility to sickness and infection 
• Increase your risk of developing heart problems, type 2 diabetes, and high blood pressure 
• Interfere with your metabolism and elevate your risk for obesity 
• Cause your relationships to suffer at work and at home 
• Lead to depression and anxiety 

The effects of sleep debt compound quickly, so the sooner you can address sleep difficulties, the better.

The good news is that many sleep problems improve and even disappear when you take the right steps to treat them. Start by implementing healthy sleep hygiene practices at home.

• Get at least 20 minutes of exposure to natural light in the morning. 
• Commit to a regular sleep schedule.
• Adopt a relaxing bedtime routine.
• Make sure your bedroom environment is cool, dark, quiet, and comfortable.
• Avoid electronics with screens in the hour before bed.
• Exercise regularly and early in the day. 
• Avoid alcohol, nicotine, and caffeine in the hours before bed. 

If you have trouble sleeping even after taking these steps, contact your doctor. With the right treatments, you can get the sleep your body needs.

• New Research Evaluates Accuracy of Sleep Trackers
• Listening to Calming Words While Asleep Boosts Deep Sleep
• Distinct Sleep Patterns Linked to Health Outcomes
• Association Between Sleep Duration and Disturbance with Age Acceleration

About Our Editorial Team

Lucy Bryan, Contributing Writer

Medically Reviewed by

Dr. Brandon Peters, Sleep Physician, Sleep Psychiatry Expert

References 7 sources.

Vandekerckhove, M., & Wang, Y. L. (2017). Emotion, emotion regulation and sleep: An intimate relationship. AIMS neuroscience, 5(1), 1–17.

Khan, M. A., & Al-Jahdali, H. (2023). The consequences of sleep deprivation on cognitive performance. Neurosciences (Riyadh, Saudi Arabia), 28(2), 91–99.

Sio, U. N., Monaghan, P., & Ormerod, T. (2013). Sleep on it, but only if it is difficult: effects of sleep on problem solving. Memory & cognition, 41(2), 159–166.

Freiberg A. S. (2020). Why We Sleep: A Hypothesis for an Ultimate or Evolutionary Origin for Sleep and Other Physiological Rhythms. Journal of circadian rhythms, 18, 2.

Kirsch, D. (2024, March). Stages and architecture of normal sleep. In S. Harding & A.Eichler (Ed.). UpToDate.

Consensus Conference Panel, Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., Tasali, E., Non-Participating Observers, Twery, M., Croft, J. B., Maher, E., … Heald, J. L. (2015). Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, 11(6), 591–592.

Maski, K. (2024, March). Insufficient sleep: Evaluation and management. In T. Scammell & A. Eichler (Ed.). UpToDate.

Learn More About How Sleep Works

How to Become a Morning Person

How Much Sleep Do You Need?

How Memory and Sleep Are Connected

What Causes Excessive Sleepiness?

What Causes Restless Sleep?

Biphasic Sleep: What It Is And How It Works

Polyphasic Sleep: Benefits and Risks

Sleep Inertia: How to Combat Morning Grogginess

REM Rebound: Causes and Effects

Do Moon Phases Affect Your Sleep?

Alpha Waves and Sleep

How Age Affects Your Circadian Rhythm

How Is Sleep Different For Men and Women?

Circadian Rhythm

Chronotypes: Definition, Types, & Effect on Sleep

Sleep Drive and Your Body Clock

8 Health Benefits of Sleep

Daylight Saving Time: Everything You Need to Know

How To Get a Good Night’s Sleep in a Hotel

Does Napping Impact Your Sleep at Night?

Does Daytime Tiredness Mean You Need More Sleep?

Why Do I Wake Up at 3 am?

Sleep Debt: The Hidden Cost of Insufficient Rest

Sleep Satisfaction and Energy Levels

How Sleep Works: Understanding the Science of Sleep

What Makes a Good Night's Sleep

What Happens When You Sleep?

Sleep and Social Media

Adenosine and Sleep: Understanding Your Sleep Drive

Oversleeping

Hypnagogic Hallucinations

Hypnopompic Hallucinations

What All-Nighters Do To Your Cognition

Long Sleepers

How to Wake Up Easier

Sleep Spindles

Does Your Oxygen Level Drop When You Sleep?

100+ Sleep Statistics

Short Sleepers

How Electronics Affect Sleep

Myths and Facts About Sleep

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Sleep Latency

Microsleep: What Is It, What Causes It, and Is It Safe?

Light Sleeper: What It Means and What To Do About It

Other articles of interest, best mattresses, sleep testing and solutions, bedroom environment, sleep hygiene.

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MORE INFORMATION

How Sleep Works Why Is Sleep Important?

Language switcher.

Sleep plays a vital role in good health and well-being throughout your life. The way you feel while you are awake depends in part on what happens while you are sleeping. During sleep, your body is working to support healthy brain function and maintain your physical health.

In children and teens, sleep also helps support growth and development. Getting inadequate sleep over time can raise your risk for chronic (long-term) health problems. It can also affect how well you think, react, work, learn, and get along with others. Learn how sleep affects your heart and circulatory system, metabolism , respiratory system, and immune system and how much sleep is enough.

This brochure describes the differences between the types of sleep needed to feel awake and to be healthy and offers tips for getting a good night’s sleep.

Heart and circulatory system

When you fall asleep and enter non-REM sleep , your blood pressure and heart rate fall. During sleep, your parasympathetic system controls your body, and your heart does not work as hard as it does when you are awake. During REM sleep and when waking, your sympathetic system is activated, increasing your heart rate and blood pressure to the usual levels when you are awake and relaxed. A sharp increase in blood pressure and heart rate upon waking has been linked to angina, or chest pain, and heart attacks .

People who do not sleep enough or wake up often during the night may have a higher risk of:

• Coronary heart disease
• High blood pressure

Hormones and sleep

Your body makes different hormones at different times of day. This may be related to your sleep pattern or your circadian clocks. In the morning, your body releases hormones that promote alertness, such as cortisol, which helps you wake up. Other hormones have 24-hour patterns that vary throughout your life; for example, in children, the hormones that tell the glands to release testosterone, estrogen, and progesterone are made in pulses at night, and the pulses get bigger as puberty approaches.

Metabolism and sleep

The way your body handles fat varies according to various circadian clocks, including those in the liver, fat, and muscle. For example, the circadian clocks make sure that your liver is prepared to help digest fats at appropriate times. Your body may handle fat differently if you eat at unusual times.

Studies have shown that not getting enough quality sleep can lead to:

• Higher levels of the hormones that control hunger, including leptin and ghrelin, inside your body
• Decreased ability to respond to insulin
• Increased consumption of food, especially fatty, sweet, and salty foods
• Decreased physical activity
• Metabolic syndrome

All of these contribute to overweight and obesity .

Respiratory and immune systems

During sleep, you breathe less often and less deeply and take in less oxygen. These changes can cause problems in people who have health problems such as asthma or chronic obstructive pulmonary disease (COPD) . Asthma symptoms are usually worse during early morning sleep. Likewise, breathing problems in people who have lung diseases such as COPD can become worse during sleep.

Sleep also affects different parts of your immune system, which become more active at different times of day. For example, when you sleep, a particular type of immune cell works harder. That is why people who do not sleep enough may be more likely to get colds and other infections.

Lung Health Basics: Sleep

People with lung disease often have  trouble sleeping. Sleep is critical to overall health, so take the first step to sleeping better: learn these sleep terms, and find out about treatments that can help with sleep apnea.

Problems with thinking and memory

Sleep helps with learning and the formation of long-term memories. Not getting enough sleep or enough high-quality sleep can lead to problems focusing on tasks and thinking clearly. Read our Sleep Deprivation and Deficiency page for more information on how lack of sleep affects performance of daily activities, including driving and schoolwork.

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• Review Article
• Published: 18 May 2017

The sleep-deprived human brain

• Adam J. Krause 1 ,
• Eti Ben Simon 1 ,
• Bryce A. Mander 1 ,
• Stephanie M. Greer 2 ,
• Jared M. Saletin 1 ,
• Andrea N. Goldstein-Piekarski 2 &
• Matthew P. Walker 1 , 2  

Nature Reviews Neuroscience volume  18 ,  pages 404–418 ( 2017 ) Cite this article

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• Learning and memory
• Sleep deprivation
• Working memory

Sleep deprivation triggers a set of bidirectional changes in brain activity and connectivity, depending on the specific cognitive or affective behaviours engaged.

Changes in brain activity are observed when averaged across a session of task performance and during on-task performance, wherein marked brain network instability seems to be a neural hallmark of sleep deprivation.

Not all changes in brain function that are associated with sleep loss are maladaptive and thus represent deficiencies, as some predict resilience in behavioural ability and are therefore compensatory.

These basic scientific findings offer causal mechanistic insights into select neurological and psychiatric disorders in which abnormalities in sleep and cognition or emotion are highly comorbid, indicating that sleep intervention is an underappreciated and novel target for disease treatment and/or prevention.

The robust neural and behavioural phenotypes characterized by this Review can inform debates regarding sleep recommendations for both public and professional health policies, especially in light of the escalating sleep-loss epidemic prevalent throughout industrialized nations.

How does a lack of sleep affect our brains? In contrast to the benefits of sleep, frameworks exploring the impact of sleep loss are relatively lacking. Importantly, the effects of sleep deprivation (SD) do not simply reflect the absence of sleep and the benefits attributed to it; rather, they reflect the consequences of several additional factors, including extended wakefulness. With a focus on neuroimaging studies, we review the consequences of SD on attention and working memory, positive and negative emotion, and hippocampal learning. We explore how this evidence informs our mechanistic understanding of the known changes in cognition and emotion associated with SD, and the insights it provides regarding clinical conditions associated with sleep disruption.

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Acknowledgements

This work was supported by awards R01-AG031164, R01-AG054019, RF1-AG054019 and R01-MH093537 to M.P.W. from the US National Institutes of Health.

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Adam J. Krause, Eti Ben Simon, Bryce A. Mander, Jared M. Saletin & Matthew P. Walker

Helen Wills Neuroscience Institute, University of California, Berkeley, 94720–1650, California, USA

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Abnormal sleep that can be described in measures of deficient sleep quantity, structure (reflected by, for example, sleep cycle architecture) and/or sleep quality (assessed using, for example, spectral electroencephalogram power).

In functional MRI, the statistical association between time series of blood-oxygen-level-dependent signal in two or more anatomically distinct brain regions.

The ability to selectively maintain focus on behaviourally relevant stimuli, while disregarding irrelevant stimuli.

The ability to maintain, manipulate and integrate mental representations of relevant information even when it is no longer present in the environment.

Also called 'homeostatic sleep drive' or 'Process S'. A set of homeostatic neurobiological processes that increase the likelihood of sleep, or 'sleep propensity'.

The state associated with a reduction (but not total absence) of sleep in the prior night or nights, usually ranging from 1–6 hours of sleep reduction. Sleep restriction is chronic if it persists for more than 24 hours.

(DMN). Collection of brain areas, including midline frontoparietal regions, that usually disengage during externally driven, goal-directed task performance and re-engage upon task termination.

A bilateral brain network with core regions in the frontal and parietal lobes that exerts top-down control of sensory cortex to bias stimulus processing.

Acting without deliberation, or choosing short-term gains over long-term gains.

Relating to corporeal information propagated by the spinal cord to brain regions involved in the sensation and coordination of bodily functions and associated behaviours.

A test of reward processing that challenges the participant to maximize their earnings by forgoing short-term gains in return for eventual long-term gains.

The state associated with a complete absence of sleep in the prior night or nights.

(BART). A computerized measure of risk-taking behaviour. Participants are rewarded for inflating a 'balloon' but lose their reward if they overinflate and 'burst' the balloon.

The likelihood of an organism maintaining the state of sustained wakefulness.

An endogenous compound involved in biochemical and neuromodulatory processes, including metabolism and sleep–wake regulation. It accumulates extracellularly with time spent awake and dissipates during slow-wave sleep.

Measured subjectively, by means of self-reported perception of prior sleep, and objectively, using sleep-stage or quantitative electroencephalography sleep measures.

(REM). Also known as paradoxical sleep. Sleep characterized by high-frequency, low-amplitude desynchronized electroencephalogram (particularly in the theta band), rapid eye movements, muscle paralysis and dreaming.

(NREM). A type of sleep that consists of sleep stages 1–4 and that occurs towards the beginning of a sleep episode, and reflects homeostatic sleep processes.

Stage 3 and stage 4 of non-rapid eye movement sleep that is characterized by low-frequency ( ∼ 0.8–4 Hz), high-amplitude synchronized electroencephalogram (called delta waves).

Synchronized phasic bursts of electrical activity often measured in the cortex or scalp surface electroencephalogram lasting several seconds in the 11–15 Hz frequency range.

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Krause, A., Simon, E., Mander, B. et al. The sleep-deprived human brain. Nat Rev Neurosci 18 , 404–418 (2017). https://doi.org/10.1038/nrn.2017.55

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Published : 18 May 2017

Issue Date : July 2017

DOI : https://doi.org/10.1038/nrn.2017.55

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Importance of Sleep Essay | Essay on Importance of Sleep for Students and Children in English

February 13, 2024 by Prasanna

Importance of Sleep Essay:  Sleep is one of the most important things you need to do for your body because it is your body’s way of recharging its batteries. When you begin to feel sleepy at night, it means that you have reached the limit that your body has, and you should sleep so that you do not over-exert yourself.

Many people don’t get enough sleep at night, mostly because so many of us have turned into night owls who love to do so many things at night instead of the daytime. These are terrible habits, and we must learn to get rid of them by paying attention to the importance of sleep. For example, a bad habit like this would be watching TV shows late at night despite knowing that we have to wake up early the next morning.

You can also find more  Essay Writing  articles on events, persons, sports, technology and many more.

Long and Short Essays on Importance of Sleep for Students and Kids in English

Let’s look at some essays of different, increasing word lengths to know and understand the importance of sleep. These ‘Importance of Sleep’ Essays can also be like your inspiration to write your essay about the same.

Short Essay on Importance of Sleep 150 Words in English

Short Essay on Importance of Computer is usually given to classes 1, 2, 3, 4, 5, and 6.

When we sleep, the brain recharges itself and heals our bodies in whichever parts we need healing. When we sleep, our blood vessels and circulatory system heal themselves. If you have a bruise, you will notice that it has healed a little bit when you go to sleep and wake up in the morning. Sleep does the same thing for the rest of the body as well, and it is essential to allow your batteries to charge while you heal yourself.

Many of us struggle with our sleep because of the prevalence of mobile phones and other addictive screens in our lives. Some severe problems can enter our lives when we do not get enough sleep. This can range from mental health problems like depression and anxiety to even physical ailments and issues like diabetes, cardiac arrest, obesity, high blood pressure, etc. We must be careful and get a good 6-8 hours of sleep every night.

The average hours that one adult should be sleeping every night is 8 hours, or you can give or take one or two hours. The problem with all the generations in the world is that there are so many disturbances around us that can easily distract us from what is essential. One such example of this is mobile phones – it is easy to get addicted to mobile phones that contain an entire world and keep scrolling through it instead of going to sleep.

It is essential to understand the reason why sleep is vital. Getting enough sleep helps heal your bodies from any pain or injuries; it betters your immune system, cognitive memory, and thinking capacity. Furthermore, getting adequate sleep is vital for keeping our hearts and other systems clean and with a good bill of health. Without getting a good number of hours worth of sleep at night, we are putting ourselves at the risk of mental health disruptions as well as physical disorders and problems such as depression, anxiety, heart attacks, obesity (leading to various other issues), and even exhaustion which can ultimately disrupt one’s life. We must get enough sleep to look and feel fresh and healthy every day.

Introduction

Many of us do not realise the importance that a good night’s sleep holds in our lives. It is so important to sleep well at night to prevent us from getting health problems which can be disruptive for our whole lives. Let’s talk a little bit more about the importance of sleep in our lives.

Healthy Living with Good Sleep

It is essential to sleep well to live a healthy life. There are many health benefits of getting a good night’s sleep, and there are many hindrances to when you don’t get a good night’s sleep. The benefits of good sleep are that it can boost your immune system, boost your cardiovascular health, improve our abilities to think and remember things more clearly, and contain our mental health by preventing some symptoms of anxiety and depression. Sleep also helps us out with containing our exhaustion of course, the best thing to do when you are tired is to go to sleep and regain the energy you need to carry forth with your life. Most importantly, sleeping well and sleeping enough helps prevent obesity, diabetes, heart problems, and various other issues.

We must all sleep for about 8 hours in our adult lives. It can be about an hour less or an hour more, but think about it this way – you must spend about one third to one-fourth of your day recharging your batteries to get ready for the remainder of the days.

You can also read many interesting facts equipped about the importance of sleep essay furthermore in the given here, Importance of sleep essay. Never miss it!

Importance of Sleep Essay 400 Words in English

Sleep is one of the most essential and inevitable things that we have to do in our lives. Whether you eat food or drink water, sleep is inevitable because it’s what the body does naturally. Sometimes it can be tough to get a full night’s sleep, but it is imperative to try.

The Trio of Good Health

We can deny nothing about the fact that there are three things we need to improve our lives – a good diet with tonnes of nutrition, an exercise routine, and, of course, a good night’s sleep every day. These are the three things that are very imperative in our lives to inculcate and follow. Sleeping well has impressive health benefits, such as improving our cardiovascular health and preventing obesity, which even come a lot of other problems. A balanced diet filled with nutritious foods helps us remain fit and healthy, and a good exercise plan will be good for the same, too. Sleeping enough also helps us out with our strength and performance during exercise. Thus, it is a good cycle that we should create for ourselves.

Benefits of Good Sleep

There are several benefits of getting a good sleep at night. It helps you maintain your body weight so that you do not become obese and add to this; there’s also the fact that people who sleep well at night often eat less than those who don’t, which also helps with the weight. Getting adequate sleep also increases your productivity by making you feel more energetic and giving you the time you need to rest. It also helps our lives be in a good mood, and good sleep puts a person in a good mood. Sleeping enough also allows our minds to function correctly and in a better way. Thus we can think better, and we also have a better memory power upon sleeping enough.

Getting adequate sleep is incredibly vital to our mental health and physical well-being. If we do not get enough sleep, we might get burnt out and not be able to carry out our lives in the way that we should be able to. Without the ability to do this, life can become painful and full of difficulties that may become complex over time. Thus, we must all take the initiative in our own lives to sleep on time and wake up on time to prevent any mental or physical blockages and hindrances.

Long Essay on Importance of Sleep 500 Words in English

Long Essay on Importance of Computer is usually given to classes 7, 8, 9, and 10.

Sleep is one of the most essential parts of our lives; still, most of us neglect it as though there’s nothing wrong with that. It is understandable that we barely ever get any time to rest when we have a hectic life. For so many of us workaholics, sleeping can even seem like something you can do later, that there are more things you can do in the time that you could be sleeping. However, working like this may be alright for a short while, but not getting enough sleep for a long-stretched period has been found to have terrible effects on the body in the long run. We must all learn how to take care of ourselves, and this begins by forming a good routine with an adequate amount of sleep inculcated in it, alongside a good diet and regular exercise.

It is a lesser-known fact that sleeping well and sleeping a fair amount of hours when we are supposed to supplements the maintenance of our weight – this means that if you sleep better, you’re less likely to put on more weight! This is corroborated because those who sleep more need fewer calories to function in a day, as they are more refreshed and energised and thus require less food to keep them afloat throughout the day calories mean less weight.

Sleep is when our body and brains regenerate, meaning that your blood vessels and your heart and the other parts of your body heal themselves while you are sleeping. Think about it this way – you are not doing anything, your eyes are closed, and at this time, your brain has no other work because you are not conscious of doing anything in particular that the brain needs to function for. Thus, this is the best time for your body to heal itself. You’ll notice that when you wake up after getting an injury the previous day, the bruises may have already begun to heal – scabs are created in the process of healing through the night while you sleep. Thus, sleep is so crucial for healing the body.

Getting your good 7-9 hours of sleep every night is imperative for our bodies to work well the next day. Sleeping removes the tiredness from our bodies, and it rejuvenates and re-energises us for the next day. With adequate sleep, we can focus on our work better, we can do more things in our day to make it more productive, and we will be able to think, read and do everything else much better through the course of the day with good sleep.

What Happens When We Don’t Sleep Well?

Not sleeping enough is one of the worst things that a person can do to their bodies. As mentioned before, sleeping is great for rejuvenating our bodies and healing our systems inside. So, it is the complete opposite that takes place when we don’t get enough sleep.

If we do not get enough sleep at night, we will end up with terrible health. Most of us end up binge-watching television shows, movies, and even things like YouTube videos at night, and we usually do this at night because, in the daytime, we generally remain busy with other things, like school, office, other work, running errands, and stuff like that. We all think that because we do a lot of work in the daytime, the nighttime is, in a way, free time for us to do as we want. However, this is not the right way to go about life.

We need to get enough sleep because, without it, our blood vessels and heart and other organs as such will stop healing by themselves. Without adequate sleep daily, our minds will always be occupied by one thing or another, especially about how tired we all may feel, and how we want to sleep. Sadly, many us don’t even realise this, and go about their day without sleeping much without knowing how it can affect them in the long run.

Risks for all kinds of health issues, including physical and mental health go up manifold without getting a good night’s sleep every day. Depression, anxiety, stress disorders, sleep disorders, heart attacks, diabetes, obesity, etc. are just a few of the dangers that come from not sleeping well at night.

How Should I Get More Sleep?

Good sleep does not necessarily mean that you get your 8 hours a night of sleep, which is enough. No, that is not enough – it also matters that the quality of this sleep is good. If you go to sleep with your mind disturbed, you will have disturbed sleeping – maybe you will have trouble falling off to sleep in the first place, or even keep on waking up at night because of nightmares and similar things.

The best ways to get some great sleep at night would be to turn off your phone early, maybe at 10 pm or 11 pm, and only turn it back on when you wake up in the morning, possibly at 7 am to 8 am. This is the best way to get more sleep.

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Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials

Alexander j. scott.

a Keele University, School of Psychology, Keele, UK

Thomas L. Webb

c Department of Psychology, The University of Sheffield, UK

Marrissa Martyn-St James

b School of Health and Related Research (ScHARR), The University of Sheffield, UK

Georgina Rowse

d Clinical Psychology Unit, Department of Psychology, The University of Sheffield, UK

Scott Weich

Associated data.

All data and analysis code are freely available on the Open Science Framework under a creative commons 4.0 license (for access, see [ 73 ]).

The extent to which sleep is causally related to mental health is unclear. One way to test the causal link is to evaluate the extent to which interventions that improve sleep quality also improve mental health. We conducted a meta-analysis of randomised controlled trials that reported the effects of an intervention that improved sleep on composite mental health, as well as on seven specific mental health difficulties. 65 trials comprising 72 interventions and N  = 8608 participants were included. Improving sleep led to a significant medium-sized effect on composite mental health ( g+  = −0.53), depression ( g+  = −0.63), anxiety ( g+  = −0.51), and rumination ( g+  = −0.49), as well as significant small-to-medium sized effects on stress ( g+  = −0.42), and finally small significant effects on positive psychosis symptoms ( g+  = −0.26). We also found a dose response relationship, in that greater improvements in sleep quality led to greater improvements in mental health. Our findings suggest that sleep is causally related to the experience of mental health difficulties. Future research might consider how interventions that improve sleep could be incorporated into mental health services, as well as the mechanisms of action that explain how sleep exerts an effect on mental health.

Does improving sleep lead to better mental health? A meta-analysis of randomised controlled trials

Problems sleeping are common. A review of several hundred epidemiological studies [ 1 ] concluded that nearly one-third of the general population experience symptoms of insomnia (defined as difficulties falling asleep and/or staying asleep), between 4% and 26% experience excessive sleepiness, and between 2% and 4% experience obstructive sleep apnoea. Additionally, a recent study of over 2000 participants reported that the prevalence of ‘general sleep disturbances’ was 32% [ 2 ] and Chattu et al. concluded on the basis of a large systematic review of the evidence that public and health professionals need to be more aware of the adverse effects of poor sleep [ 3 ]. Mental health problems are also common, with around 17% of adults experiencing mental health difficulties of varying severities [ 4 ], and evidence from large nationally representative studies suggesting that mental health difficulties are on the increase [ 5 ]. Sleep and mental health are, therefore, global public health challenges in their own right, with each having substantive impacts on both individuals and society [ 3 , 6 , 7 ]. However, problems sleeping and mental health difficulties are also intrinsically linked [ 8 , 9 ]. It was previously assumed that mental health difficulties led to problems sleeping [ 10 , 11 ]; however, the reverse may also be true [ 12 ], such that poor sleep contributes to the onset, recurrence, and maintenance of mental health difficulties [ [13]∗ , [14] , [15]∗ , [16] , [17] ]. Therefore, the extent to which there is a causal relation between (poor) sleep and (worse) mental health and the possibility that interventions designed to improve sleep might be able to reduce mental health difficulties warrants investigation.

Evidence on the relationship between sleep and mental health

The association between sleep and mental health is well documented [ 9 , 13 , [18] , [19] , [20] , [21] , [22] , [23]∗ ]. For example, people with insomnia are 10 and 17 times more likely than those without insomnia to experience clinically significant levels of depression and anxiety, respectively [ 24 ]. Furthermore, a meta-analysis of 21 longitudinal studies reported that people with insomnia at baseline had a two-fold risk of developing depression at follow-up compared with people who did not experience insomnia [ 13 ]. Although research most commonly studies the associations between insomnia and depression and anxiety, there is also evidence that problems sleeping are associated with a variety of mental health difficulties. For example, poor sleep has also been associated with post-traumatic stress [ 25 ], eating disorders [ 26 ], and psychosis spectrum experiences such as delusions and hallucinations [ 23 , 27 ]. Studies have also found that specific sleep disorders, such as sleep apnoea [ 28 ], circadian rhythm disruption [ 29 ], restless leg syndrome [ 30 ], excessive daytime sleepiness and narcolepsy [ 31 , 32 ], sleepwalking [ 33 ], and nightmares [ 34 ] are all more prevalent in those experiencing mental health difficulties.

Unfortunately, most research on the association between sleep and mental health is observational in design. While informative, inferring causation from such studies is difficult. For example, cross-sectional designs tell us that variables are associated in some way, but they cannot say whether one variable precedes the other in a causal chain [ 35 ]. Longitudinal designs provide stronger evidence, but are prone to residual confounding [ [36] , [37] , [38] ] and other forms of bias that limit causal inference [ [39] , [40] , [41] , [42] , [43] ]. The best evidence is provided by studies that randomly allocate participants to experimental and control conditions to minimise the effects of potential confounds [ 44 , 45 ]. Therefore, to establish whether sleeping problems are causally associated with mental health difficulties, it is necessary to experimentally manipulate sleep to see whether changes in sleep lead to changes in mental health over time (i.e., the interventionist approach to causation, [ 46 ]).

Many RCTs have examined the effect of interventions designed to improve sleep (typically cognitive behavioural therapy for insomnia, CBTi), on mental health (typically depression and anxiety). There have also been attempts to meta-analyse some of these RCTs and quantify their effects on mental health outcomes [ [47]∗ , [48] , [49] , [50] ]. However, even these meta-analyses do not permit robust conclusions as to the causal impact of sleep on mental health outcomes for several reasons. First, previous reviews have included studies that did not successfully manipulate sleep (i.e., the intervention did not improve sleep relative to controls). It is not possible to conclude whether sleep is causally linked to mental health if the experimental manipulation of sleep is unsuccessful [ 51 ]. Indeed, these studies simply tell us that it can sometimes be difficult to improve sleep in the first place. Second, reviews have tended to examine the effect of interventions targeting sleep on mental health at the first post-intervention time point. This is problematic for two reasons; 1) there is no temporal lag between the measurement of sleep and measurement of mental health (a key tenet of causal inference); and 2) effects are limited to the short-term where they are likely to be strongest. Third, the focus of previous reviews has been limited to depression and anxiety only, and typically limited to CBTi interventions. Therefore, the effect of improving sleep on other mental health outcomes, using different approaches to intervention, is limited. Finally, to date there has been no or limited attempts to investigate variables that influence – or moderate – the impact of interventions that improve sleep on mental health. It is crucial that the impact of such variables is systematically examined to understand whether the effect of improving sleep on mental health differs across populations, settings, and study designs.

The present review: an interventionist approach to causation

The present review sought to address these issues to provide an accurate and robust estimate of the effect of changes in sleep quality (i.e., as a result of an intervention) on changes in mental health. To test this empirically, we identified randomised controlled trials that successfully manipulated sleep in an intervention group relative to controls, and then measured mental health at a later follow-up point. We did not limit the scope of interventions to CBTi, or the measures of mental health to solely depression and/or anxiety. Instead, we included any intervention designed to improve sleep that produced a statistically significant effect on sleep quality relative to controls and examined the effect of that improvement in sleep on any subsequent mental health outcome. To better isolate the effect of improved sleep on mental health, we excluded interventions that included specific elements targeting mental health (e.g., CBT elements for depression). Given the (potentially) high degree of heterogeneity between studies that this approach might create, we examined the effect of different study characteristics and outcomes using moderation analyses. Our primary hypothesis is that interventions that significantly improve sleep will lead to significantly improved mental health at follow-up.

Eligibility criteria

To be included in the present review, studies needed to 1) be a randomized controlled trial that tested an intervention designed to improve sleep; 2) produce a statistically significant effect on sleep quality when compared to a control group or an alternative treatment, 3) report a measure of mental health subsequent to the measure of sleep quality, 4) report sufficient data to compute an effect size representing the impact of the intervention on both sleep quality and mental health, 5) be written in English, or translatable using available resources. In order to reliably and validly assess the independent contribution of changes in sleep on mental health outcomes among adult populations, studies were excluded if 1) the intervention contained elements that specifically target a mental health problem in addition to elements that target sleep; or 2) recruited children and young people (i.e., <18 years of age).

Search strategy

First, we searched MEDLINE (1946 to present), Embase (1974 to present), PsycINFO (1967 to present), and The Cochrane Library (1898 to present) using the Cochrane Highly Sensitive Search Strategy (i.e., HSSS, [ 52 ]) to identify RCTs that included terms relating to sleep quality and/or sleep disorders, and mental health (see Table 1 for a list of the search terms and Supplementary Material 1 for an example search strategy). Second, the reference lists of extant reviews of the relationship between sleep and mental health were searched for any potential articles. Third, a search for any unpublished or ongoing studies was conducted by searching online databases including White Rose Online, The National Research Register, WHO approved clinical trial databases (e.g., ISRCTN), and PROSPERO. Searches were originally conducted in May 2019 and then updated in February 2021.

Table 1

Search terms used to identify RCT's that examined the effect of improving sleep on mental health.

Notes : HSSS for RCTs = highly sensitive search strategy for randomised controlled trials, OCD = obsessive compulsive disorder, PTSD = post-traumatic stress disorder.

Data management and study selection

We followed PRISMA guidelines [ 53 ] when selecting studies. The first phase of screening removed duplicate records and records that were clearly ineligible based on the title and/or abstract. The second phase of screening cross-referenced full-text versions of articles against the inclusion criteria, with eligible records included in the present review, and ineligible records excluded along with reasons for exclusion. Records were screened by two members of the review team, and a sub-sample of 10% of each reviewer's records were second checked by the other reviewer, with almost perfect agreement between the reviewers ( kappa  = 1.00 and 0.99).

Data extraction

Data was extracted from included studies using a standardized form and an accompanying manual detailing each variable for extraction. In addition to extracting statistical data to compute effect sizes, data pertaining to source characteristics of included studies (e.g., publication status, year, impact factor), characteristics of the sample (e.g., age, type of mental health problem), the study (e.g., the nature of the comparison group, length of follow-up), and the intervention (e.g., intervention type, mode of delivery) was also extracted.

Outcomes and prioritization

Measuring improvements in sleep.

The concept of ‘improved sleep’ is multifaceted and can mean different things to different people [ [54] , [55] , [56] ]. Consequently, one challenge for the proposed review was to ensure that included studies assessed a similar notion of improved sleep so that they could be meaningfully combined using a single metric. Therefore, we specified that primary studies reported a measure that reflected the overall quality of sleep experienced by participants. The concept of sleep quality can also be subjective [ 54 ]; however, broadly speaking, sleep quality consists of sleep continuity (e.g., sleep onset, sleep maintenance, and number of awakenings) and daytime impact (e.g., the extent to which the person feels refreshed on waking and throughout the day, see [ 54 , 57 ]). We used the following hierarchy to decide which outcome measure(s) to use to estimate an effect size (in descending order of prioritization); 1) self-report measures of global sleep quality (e.g., the Pittsburgh Sleep Quality Index); 2) outcomes specific to a given sleep disorder that assess sleep continuity and impact on daily life (e.g., the Insomnia Severity Index); and 3) individual components of self-reported sleep continuity aggregated to form a single composite effect size (e.g., the average effect of intervention on sleep onset latency (SoL) and wake after sleep onset (WASO)).

Measuring mental health

We examined the effect of improving sleep on 1) composite mental health (which included all mental health outcomes reported across studies, see Table 2 for outcomes), and 2) specific mental health difficulties in isolation (e.g., depression separately from other mental health outcomes). We computed the between-group effect of improving sleep on each mental health outcome reported by the study at the furthest follow-up point available. This strategy provides a stringent test of the effect of improving sleep on mental health outcomes in the sense that any changes need to have been maintained over time. In line with previous reviews [ 58 ], these effect sizes were then averaged to form a ‘composite’ measure of mental health. As with the measures of sleep quality, we prioritized self-report measures of mental health rather than observer-rated measures, as arguably it is the subjective experience of mental health problems that is most important [ 59 ].

Table 2

Summary of studies included in the review.

Note : ∗ p  < 0.05, ∗∗ p  < 0.01, ∗∗∗ p  < 0.001. CBTi = cognitive behavioural therapy for insomnia, dx = diagnosis, IRT = image rehearsal therapy, MH = mental health, n e  = number of participants in intervention group, n c  = number of participants in the control group, PTSD = post-traumatic stress disorder, TaU = treatment as usual, WLC = wait list control. ab Subscript indicates that the study reports multiple eligible interventions in the same study, in these situations both interventions were included as separate studies in the analysis and the control was halved accordingly.

Risk of bias

Risk of bias was assessed using the risk of bias assessment criteria developed by the Cochrane Collaboration [ 60 ]. RCTs were classified as being at overall risk of bias according to three of the six domains – 1) allocation concealment, 2) blinding of outcome assessment and 3) completeness of outcome data (attrition). RCTs judged as being at low risk of bias for all three domains were judged at overall low risk of bias. RCTs judged as being at high risk for any of the three domains were judged as overall high risk of bias. RCTs judged as a mix of low and unclear risk on these three domains, or all unclear were judged as unclear with respect to risk of bias.

Estimating effect sizes

Hedges g and the associated standard error were estimated using the means and standard deviations reported by each of the primary studies. Where means and standard deviations were not reported, effect sizes were estimated by converting relevant summary statistics into Hedges g . Where studies reported multiple outcome measures for the same/similar constructs (e.g., several measures of depression), effect sizes were computed for each outcome and then meta-analysed in their own right to form one overall effect.

Meta-analytic approach

All analyses were conducted in R [ 61 ], using the ‘ esc ’ [ 62 ], ‘ meta’ [ 63 ], ‘ metafor’ [ 64 ], ‘ dmetar ’ [ 65 ], and ‘ robvis ’ [ 66 ] packages. The pooled, sample-weighted, average effect size was computed using a random effects model as effect sizes between studies are likely to vary considerably [ 67 ]. Following Cohen's recommendations [ 68 ], g  = 0.20 was taken to represent a ‘small’ effect size, g  = 0.50 a ‘medium’ effect size and g  = 0.80 a ‘large’ effect size. The I 2 statistic was used to assess heterogeneity of effect sizes across the included studies and was interpreted according to the classifications suggested by Higgins et al. [ 69 ], where I 2  = 25% indicates low heterogeneity, I 2  = 50% indicates moderate heterogeneity, and I 2  = 75% indicates high heterogeneity. Publication bias was assessed via visual inspection of a funnel plot and Egger's test [ 70 ]. Additionally, Orwin's formula [ 71 ] was used to determine the fail-safe n . Finally, outliers were defined as any effect size for which the confidence intervals did not overlap with the confidence interval of the pooled effect [ 72 ]. We conducted a sensitivity analysis examining the effect of outliers for each outcome by rerunning the analysis with any outlying effect sizes removed.

Subgroup analyses

Moderation analysis was conducted to identify variables that were associated with the effect of improving sleep on mental health outcomes. A minimum of three studies representing each moderator level category was required in order to conduct moderation analysis. For categorical variables, the analysis was based on a mixed effects model, in that the pooling of effect sizes within each moderator level was based on a random effects model, while the comparison of effect sizes between levels was based on a fixed effects model. The Q statistic was then used to assess whether effect sizes were significantly different between moderator levels. For continuous variables, sample-weighted meta-regression was used to investigate the impact of the moderator on mental health effect sizes.

Data availability statement

Study selection.

Fig. 1 shows the flow of records through the review. Systemic searches of the published and grey literature retrieved a total of 21,733 records, which was reduced to 15,139 after duplicates were removed. Of these records, 14,687 (97%) were excluded in the first stage of screening, leaving 452 full-text records to be screened. Of these records, 387 (86%) were cross-referenced against the review eligibility criteria and excluded (see Fig. 1 for a breakdown of reasons and Supplementary Materials 2 for a list of the studies excluded at this stage), leaving 65 records for inclusion in the meta-analysis.

PRISMA diagram showing the flow of studies through the review.

Study characteristics

Table 2 describes key characteristics of the included studies. The 65 studies provided 72 comparisons between an intervention that successfully improved sleep quality vs. a control group.

Participants

A total of N  = 8608 participants took part across the 72 interventions. 38 of the comparisons (53%) included participants with a comorbid physical or mental health problem, while 31 (43%) reported no comorbid health problems, and 3 (4%) reported insufficient detail to make a judgement. Of the 38 comparisons including participants with comorbid health problems, 18 (47%) reported mental health diagnoses, and 20 (53%) had physical health problems.

Outcome measures

The majority of comparisons (61, 85%) reported a measure of depression, but 33 (46%) reported a measure of anxiety, 6 (8%) reported a measure of stress, 5 (7%) reported measures of psychosis spectrum experiences (e.g., total, positive, and negative symptoms), 9 (13%) reported a measure of general mood, 2 (3%) reported post-traumatic stress disorder outcomes, 2 (3%) reported measures of suicidal ideation, 4 (6%) reported rumination outcomes, and 1 (2%) reported a measure of psychological burnout.

Interventions and comparisons

Most interventions were multi-component CBTi (53, 74%), but interventions also involved acupuncture (7, 10%), pharmacological treatments (2, 3%), sleep hygiene alone (2, 3%), sleep restriction alone (2, 3%), Tai Chi (2, 3%), CBT for nightmares (1, 2%), herbal remedies (1, 2%), walking (1, 2%), and yoga (1, 2%). Interventions were most often compared against an active control group (34, 47%), but were also compared to waitlist control groups (25, 35%), and groups receiving treatment as usual (13, 18%). On average participants’ mental health was followed-up 20.5 weeks post-intervention (median = 12 weeks post-intervention), with the earliest follow-up being 4-weeks post-intervention, and the furthest follow-up 156-weeks (three years) post intervention.

Manipulation check: did sleep quality improve significantly in the intervention group relative to controls?

Before we examined the effect of improving sleep quality on subsequent mental health, we confirmed that studies included in the review successfully improved sleep quality. The interventions had large and statistically significant effects on sleep quality at the earliest follow-up point reported ( g +  = −1.07, 95% CI = −1.26 to −0.88, p  < 0.001), although heterogeneity between studies was substantial ( I 2  = 79%, Q  = 331.93, p  < 0.001). After twelve outlying effect sizes were removed, the effect of the interventions on sleep quality remained large and statistically significant ( g +  = −0.97, 95% CI = −1.07 to −0.88, p  < 0.001), and heterogeneity was reduced to moderate levels ( I 2  = 43%, Q  = 102.32, p  < 0.001). These findings suggest that the primary studies included in the present review successfully manipulated sleep quality, even after accounting for outliers.

What effect do improvements in sleep quality have on mental health?

Table 3 presents the effect of improving sleep quality on composite mental health outcomes, and on measures of depression, anxiety, stress, psychosis spectrum experiences, suicidal ideation, PTSD, rumination, and burnout.

Table 3

The effect of improving sleep on mental health outcomes.

Notes : ∗∗∗ p  < 0.001, ∗ p  < 0.05, PANSS = Positive and Negative Symptoms Scale, PTSD = Post Traumatic Stress Disorder.

Composite mental health

On average, the 72 interventions that successfully improved sleep quality had a statistically significant, medium-sized effect on subsequent composite mental health outcomes, ( g +  = −0.53, 95% CI = −0.68 to −0.38, p  < 0.001); however, there was substantial heterogeneity between the effect sizes, ( I 2  = 76%, Q  = 291.94, p  < 0.001). After re-running the analysis with eleven outlying effect sizes removed, the effect of improving sleep on composite mental health outcomes was small-to-medium sized but still statistically significant, ( g +  = −0.42, 95% CI = −0.49 to −0.34, p  < 0.001) and now relatively homogeneous ( I 2  = 20%, Q  = 75.24, p  = 0.0888). See Fig. 2 for a forest plot.

Forest plot showing the effect of improving sleep on composite mental health outcomes.

Interventions that successfully improved sleep quality had a statistically significant, medium-sized effect on depression across 61 comparisons, ( g +  = −0.63, 95% CI = −0.83 to −0.43, p  < 0.001); however, once again, there was substantial heterogeneity, ( I 2  = 81%, Q  = 322.09, p  < 0.001). After re-running the analysis with nine outlying effect sizes removed, the effect of improving sleep on depression remained medium-sized, ( g +  = −0.47, 95% CI = −0.57 to −0.37, p  < 0.001), with moderate heterogeneity, ( I 2  = 32%, Q  = 74.86, p  = 0.0164). See Fig. 3 for a forest plot.

Forest plot showing the effect of improving sleep on depression.

Interventions that successfully improved sleep quality had a statistically significant, small-to-medium sized effect on anxiety across 35 comparisons, ( g +  = −0.50, 95% CI = −0.76 to −0.24, p  < 0.001), with substantial levels of heterogeneity, ( I 2  = 82%, Q  = 187.02, p  < 0.001). After re-running the analysis with four outlying effect sizes removed, the effect improving sleep on anxiety outcomes was small-to-medium sized, but still statistically significant, ( g +  = −0.38, 95% CI = −0.49 to −0.27, p  < 0.001), with lower levels of heterogeneity, ( I 2  = 43%, Q  = 52.49, p  = 0.0067). See Fig. 4 for a forest plot.

Forest plot showing the effect of improving sleep on anxiety.

Interventions that successfully improved sleep quality had a statistically significant, small-to-medium sized effect on stress ( g +  = −0.42, 95% CI = −0.79 to −0.05, p  = 0.033), across six comparisons. There were moderate levels of heterogeneity ( I 2  = 55%, Q  = 11.05, p  = 0.05), but there were no outlying effect sizes. See Fig. 5 for a forest plot.

Forest Plot Showing the Effect of Improving Sleep on Stress, Suicidal Ideation, PTSD, and rumination.

Psychosis spectrum experiences

Interventions that successfully improved sleep quality had a small effect on total symptoms as indicated by the PANSS ( g +  = −0.17, 95% CI = −0.53 to 0.19, p  = 0.18) across three comparisons, with zero heterogeneity ( I 2  = 0%, Q  = 0.41, p  = 0.813). Interventions that successfully improved sleep quality had a small effect on positive symptoms ( g +  = −0.26, 95% CI = −0.43 to −0.08, p  = 0.014) across five comparisons, with zero heterogeneity ( I 2  = 0%, Q  = 1.71, p  = 0.788). Finally, interventions that successfully improved sleep quality had a small effect on negative symptoms ( g +  = −0.28, 95% CI = −3.22 to 2.65, p  = 0.436) across k  = 2 comparisons, with zero heterogeneity ( I 2  = 0%, Q  = 1, p  = 0.318). See Fig. 6 for a forest plot.

Forest plot showing the effect of improving sleep on psychosis spectrum outcomes.

Suicidal ideation

Interventions that successfully improved sleep quality had a small, adverse effect on suicidal ideation ( g +  = 0.10, 95% CI = −3.74 to 3.94, p  = 0.804) across two comparisons. There were low levels of heterogeneity ( I 2  = 20%, Q  = 1.25, p  = 0.263) and no outlying effect sizes. See Fig. 5 for a forest plot.

Post-traumatic stress disorder (PTSD)

Interventions that successfully improved sleep quality had a medium-to-large effect on PTSD ( g +  = −0.72, 95% CI = −2.90 to 1.46, p  = 0.149) across two comparisons, with zero heterogeneity ( I 2  = 0%, Q  = 0.59, p  = 0.442). See Fig. 5 for a forest plot.

Interventions that successfully improved sleep quality had a statistically significant, medium sized effect on rumination ( g +  = −0.49, 95% CI = −0.93 to −0.04, p  = 0.041) across four comparisons, with moderate heterogeneity ( I 2  = 36%, Q  = 4.65, p  = 0.1991). See Fig. 5 for a forest plot.

Only one study reported the effect of improving sleep on burnout finding almost zero effect ( g  = −0.03, CI = −0.58 to 0.52, p  = 0.917).

Moderators of the effect of improving sleep quality on composite mental health outcomes

Table 4 presents the findings of analyses evaluating categorical moderators of the effect of improving sleep quality on composite mental health outcomes and Table 5 presents analyses evaluating continuous moderators using meta-regression. Studies that found significant effects of the intervention on sleep quality reported larger effects on subsequent composite mental health, ( g  = −0.53, 95% CI = −0.68 to −0.38, p  < 0.001), than studies that did not find a significant effect of the intervention on sleep quality, ( g  = −0.12, 95% CI = −0.24 to 0.01, p  = 0.0522), a difference that was statistically significant, ( Q  = 17.59, p  < 0.001). This finding strengthens the notion that improvements in sleep are behind improvements in mental health. The effect of improving sleep on mental health was larger in studies with shorter follow-up periods, (i.e., <6 months, g + = −0.60), than in studies with longer follow-ups, (i.e., 6 months, g + = −0.18, Q  = 10.75, p  < 0.01). Furthermore, interventions that were delivered face-to-face by a clinician or therapist were associated with significantly larger effects on mental health, ( g + = −0.63), than those that were self-administered by participants, ( g + = −0.34, Q  = 4.50, p  < 0.05). Finally, there was significant variation in the size of the effect between countries ( Q  = 53.69, p  < 0.001). No other statistically significant categorical moderator effects were found. Regarding continuous moderators, meta-regression revealed a statistically significant dose–response effect for the association between the effect of interventions on sleep quality and the effect on subsequent mental health outcomes ( B  = 0.77, 95% CI = 0.52 to 1.02, p  < 0.001), suggesting that greater improvements in sleep led to greater improvements in mental health. No other continuous variables significantly moderated the effect of improving sleep on mental health.

Table 4

Categorical moderators of the effect of improving sleep on composite mental health outcomes.

Notes : CBTi = cognitive behavioural therapy for insomnia, MH = Mental Health, PH = Physical Health, TaU = treatment as usual, WLC = wait list control.

∗ p  < 0.05, ∗∗ p  < 0.01, ∗∗∗ p  < 0.001.

Table 5

Continuous moderators of the effect of improving sleep on composite mental health outcomes.

Post-hoc moderation analysis

Is the smaller effect of improving sleep on mental health at longer follow-ups associated with smaller effects on sleep quality.

We conducted further (unplanned) post-hoc analysis to investigate whether the smaller effect of improving sleep on mental health at longer follow-ups was accompanied by a reduction in the improvements to sleep quality. Studies reporting the effect of the intervention at shorter follow-ups reported larger improvements in sleep quality, ( g  = −1.03, 95% CI = −1.27 to −0.78, p  < 0.001), than those reporting longer follow-ups ( g  = −0.44, 95% CI = −0.62 to −0.27, p  < 0.001), a difference that was statistically significant, ( Q  = 14.38, p  < 0.001). This suggests that the smaller effect of improving sleep on mental health at longer follow-ups might be driven by a smaller effect of the interventions on sleep quality at longer follow-ups.

Can some of the effect of improved mental health be explained by CBTi modules that target processes associated with mental health?

Finally, although the present review excluded interventions that specifically and directly targeted mental health, some CBTi protocols include modules that might target similar processes associated with some mental health difficulties (rumination around sleep, catastrophizing over the effect of poor sleep etc.). Therefore, we compared CBTi interventions with modules that could target processes associated with mental health vs. interventions that did not include these modules (e.g., sleep restriction alone, sleep hygiene alone, herbal tea, and pharmacological intervention). There were no significant differences in the effect of improved sleep quality on mental health between CBTi interventions including modules addressing processes associated with mental health ( g  = −0.44, 95% CI = −0.59 to −0.29, p  < 0.001), relative to those that did not ( g  = −0.48, 95% CI = −0.65 to −0.32, p  < 0.001, Q  = 2.51, p  = 0.285). This finding suggests that it is the beneficial effect of improved sleep quality that confers improvements in mental health rather than the inclusion of modules that target processes associated with mental health commonly seen in CBTi protocols.

Risk of bias assessments

Fig. 7 summarizes the weighted assessment of risk of bias. Individual risk of bias judgements for included studies are presented in Supplementary Material 3 . Ten studies (15%) were judged as having low risk of bias, 29 studies (45%) were judged as high risk of bias, and 26 studies (40%) were judged as unclear. The methodological quality of the included studies was not associated with the effect of improving sleep on composite mental health outcomes, Q  = 0.72, p  = 0.395.

Weighted risk of bias summary plot.

Publication bias

A funnel plot of the effect of improving sleep quality on composite outcomes revealed asymmetry in the effect sizes (Egger's regression = −1.09, 95% CI = −1.91 to −0.28, p  < 0.05, see Fig. 8 ). Duval and Tweedie's [ 74 ] trim and fill procedure was therefore used to address the asymmetry. Ten studies were imputed resulting in a statistically significant, small-to-medium sized adjusted effect of improving sleep on composite mental health outcomes ( g +  = −0.35, 95% CI = −0.55 to −0.16, p  < 0.001). Orwin's failsafe n test suggested that an additional 4101 comparisons producing null effects would be needed to reduce the average effect of improving sleep on composite outcomes to zero. Taken together these results suggest that the effect of improving sleep on composite mental health is robust to possible publication bias.

Contrast enhanced funnel plot for the effect of improving sleep on composite mental health (solid grey markers) with imputed studies (hollow markers).

The present review used meta-analysis to synthesize the effect of 72 interventions that improved sleep quality relative to a control condition on subsequent mental health. The findings revealed that improving sleep quality had, on average, a medium-sized effect on mental health, including clear evidence that improving sleep reduced depression, anxiety, and stress. A dearth of primary studies of other mental health difficulties (e.g., psychosis spectrum experiences, suicidal ideation, PTSD, rumination, and burnout) mean that it is premature to draw definitive conclusions in these areas. It was also notable that we found a dose–response relationship between improvements in sleep quality and subsequent mental health, such that greater improvements in sleep led to greater improvements in mental health. Although there was some evidence of publication bias, the effects remained robust to correction. Taken together, the findings suggest that improving sleep leads to better mental health, therefore providing strong evidence that sleep plays a causal role in the experience of mental health difficulties.

Sleep as a transdiagnostic treatment target

The present findings support the idea that targeting sleep promotes mental health across a range of populations and experiences. The effect of improving sleep quality on composite mental health was medium-sized and statistically significant, regardless of the presence of physical and/or mental health comorbidities. This finding is particularly important given the healthcare challenges associated with multimorbidity [ 75 ] and mental and physical health problems often co-occur [ [76] , [77] , [78] , [79] ], something that appears to be increasing [ 80 ]. Consequently, it is important that the benefits of improving sleep on mental health occur even in the presence of comorbid health complaints, as was reported in the present research. Improving sleep has also been shown to improve aspects of physical health, including fatigue [ 81 ], chronic pain [ 82 , 83 ], and overall health related quality of life [ 84 ] and could reduce the cost of healthcare. For example, offering a digital CBTi intervention (Sleepio) to primary care patients was associated with an average saving of £70.44 per intervention user [ 85 ], and cost savings following sleep intervention have also been specifically reported in people with comorbid mental health difficulties such as depression [ 86 ].

Another finding to suggest that targeting sleep could promote mental health across a range of populations and experiences, is that we found no difference in the effect of improving sleep quality on mental health between those with clinically defined mental health difficulties and those with non-clinical experiences or between those recruited from clinical vs. community settings, with both groups receiving significant benefits of improved sleep on mental health. This suggests that improving sleep could prove helpful across a range of mental health severities, thus broadening the possible impact of sleep interventions within healthcare services. Finally, there is growing evidence that sleep disturbances predict the development of mental health difficulties in the future. For example, shorter and more variable sleep has been shown to be longitudinally associated with more severe hallucinations and delusional ideation in those at high-risk of psychosis [ 87 ]. The present research found that improving sleep has a significant beneficial impact on future mental health in those with non-clinical experiences, raising the possibility that delivering interventions that improve sleep early might limit the risk of developing (or exacerbating) substantive mental health difficulties. Indeed, less severe mild-to-moderate presentations of mental health difficulties can develop over time into more severe mental health diagnoses [ 88 , 89 ], therefore improving sleep might be one tool that can be used in combination with others to limit the risk of transition.

Strengths and limitations

The present review has several strengths. First, it provides a comprehensive and up-to-date search of RCTs examining the effect of improving sleep on a variety of subsequent mental health outcomes. Indeed, with 65 RCTs and N  = 8608 participants, the present review is one of the largest studies of the effect of improving sleep on mental health to date. Second, the review was specifically designed to test the causal association between sleep and mental health (i.e., RCTs only, successful sleep improvement required, temporal lag between measures etc.). To our knowledge, the review is the first to adopt this approach in the field of sleep and mental health, although the general approach has been used in other fields [ 90 ]. Finally, we provide an analysis of possible moderators of the effect of improving sleep on mental health, identifying several key moderators of the effect.

However, there are limitations that must be considered when interpreting the findings. First, relatively few studies examined the effect of improving sleep over the long term. Those that did report longer follow-ups generally found smaller effects (although still statistically significant), most likely due to the diminishing effects of interventions on sleep quality over time [ 91 ]. Consequently, it is important that interventions targeting sleep quality as a route to improving mental health seek to maintain their beneficial effects. Second, there were few primary studies for some of the outcomes included in this review. Consequently, in lieu of more studies reporting these outcomes, the inferences that we can make for mental health outcomes other than depression and anxiety are more limited. Third, although the intention of the present review was to include a broad range of sleep disturbances, most of the analyses are based on CBT interventions for insomnia. This might be due to the relationship between insomnia and mental health being the one that is historically most studied. However, it may be that our focus on sleep quality precluded some studies that do not focus on insomnia from inclusion. For example, different sleep disorders have different conceptualisations of improvement that might not include sleep quality. For example, the timing of sleep is particularly important in circadian rhythm disorders and daytime sleepiness is a key outcome in sleep apnoea research. Future research might consider examining the effect of improving specific sleep disorders on mental health by conceptualising improvements using sleep disorder specific outcomes.

Future directions

The present review highlighted several areas for future research in terms of both research and theory, and the implementation of findings in practice. First, given that mental health was measured on average around 20.5 weeks post-intervention in the primary studies, and that the effect of improving sleep on mental health significantly reduced over time, future research should examine the effect of improving sleep on mental health over the longer term. Second, although not uncommon, the majority of RCTs included in the present review were at high risk, or unclear risk or bias. Consequently, in addition to studying the effect of improving sleep over the longer term, on a range of mental health difficulties beyond depression and anxiety, we need more research at lower risk of methodological bias.

Finally, although the present research provides evidence for a causal association between sleep and mental health, it is less clear how sleep affects mental health. One potential mechanism is whether and how people regulate their emotions (e.g., in response to negative events). Indeed, evidence suggests that poor sleep can amplify the adverse effect of negative life events [ 92 , 93 ], dull the beneficial impact of positive events [ 94 ], and is associated with more frequent use of emotion regulation strategies that might be detrimental to good mental health [ 95 ]. By extension, although we are unaware of RCTs testing the effect of improved sleep on emotion regulation, changes in sleep are prospectively associated with changes in aspects of emotion regulation [ 96 , 97 ], while experimentally induced sleep deprivation is adversely linked to poorer emotion regulation [ 96 , 97 ]. Contemporary perspectives on emotion regulation (e.g., the action control perspective), draw on research on how people regulate their behaviour, to propose that regulating emotions involves three tasks, 1) identifying the need to regulate, 2) deciding whether and how to regulate, and 3) enacting a regulation strategy [ 98 ]. We propose that poor sleep quality has the potential to adversely affect anyone (or all) of the three tasks involved in effectively regulating emotions, which might go some way toward explaining the relationship between poor sleep and mental health. Therefore, we would recommend that future research includes measures of aspects of emotion regulation (e.g., the Difficulties in Emotion Regulation Scale, [ 99 ]) within experimental and longitudinal designs to elucidate possible mechanisms by which improvements in sleep benefit mental health.

In terms of practice and implementation, evidence on the effect of sleep on mental health also supports calls for routine screening and treatment of problems with sleep. Both the Royal Society for Public Health (RSPH) and the Mental Health Foundation (MHF) recommend that primary health care training should include awareness of, and skills in assessing, sleep problems [ 100 , 101 ]. Despite this and a growing body of evidence, there has been little progress to date [ 102 ]. This may reflect under-appreciation of the importance of sleep [ 103 ] and lack of training and skills in assessing and managing sleep problems [ [104] , [105] , [106] , [107] , [108] ], as well as limited time and resources [ 103 , 109 ]. Therefore, a profitable next step might be to explore barriers and facilitators to assessing sleep and delivering effective interventions in specific care settings, from both the patient and clinician perspective. Indeed, the present review also highlighted a dearth of trials that tested the effect of improving sleep on mental health outcomes in ‘real world’ settings (e.g., within existing clinical and community health services). Although some researchers are taking important steps in this area [ [110] , [111] , [112] ], there is a clear need for more trials of interventions in clinical services so that the effectiveness and implementation of such interventions in routine care can be better understood.

Conclusions

Taken together, the present research supports the view that sleep is causally related to the experience of mental health difficulties, and therefore that sleep represents a viable treatment target that can confer significant benefits to mental health, as it has been found to do for physical health. We found that improving sleep was associated with better mental health regardless of the severity of mental health difficulty (i.e., clinical vs. non-clinical) or the presence of comorbid health conditions. Poor sleep is almost ubiquitous within mental health services [ 102 , 108 , 113 , 114 ], is causally related to the experience of mental health difficulties, and represents a potential treatment target [ 105 , 115 , 116 ]. Consequently, equipping health professionals with greater knowledge and resources to support sleep is an essential next step. Future research should consider how interventions that improve sleep could be better incorporated into routine mental health care, as well as the possible mechanisms of action that might explain how sleep exerts its effects on mental health.

Research agenda

To fully harness the effect of improved sleep on mental health, it is important that future research:

• 1. Explores the barriers and possible solutions to incorporating interventions that improve sleep into mental health care services.
• 2. Tests the effect of improving sleep on mental health outcomes beyond depression and anxiety, and over the long term, using designs at low risk of methodological bias.
• 3. Investigates the possible mechanisms of action that might explain how sleep exerts its effects on the experience of mental health difficulties.

Practice points

• • Sleep is causally related to the experience of mental health difficulties and represents a viable transdiagnostic treatment target for those experiencing mental health difficulties.
• • Improving sleep has beneficial effects on the experience of mental health difficulties, regardless of the severity of those difficulties, or the presence of comorbid health conditions.
• • Healthcare professionals aiming to improve mental health (particularly depression, anxiety, and stress) should consider interventions designed to improve sleep, particularly cognitive behavioral therapy for insomnia where the evidence base is strongest.

This research was funded by the National Institute for Health Research under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG- 0817-20027). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

Acknowledgements

We thank Anthea Sutton (Information Resources Group Manager, The University of Sheffield) for her help developing the systematic search strategy and managing the records.

∗ The most important references are denoted by an asterisk.

Supplementary data to this article can be found online at https://doi.org/10.1016/j.smrv.2021.101556 .

Appendix ASupplementary data

The following are the Supplementary data to this article:

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The mechanisms of sleep function and regulation for health and cognitive performance.

Acknowledgments

Conflicts of interest.

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Fabbri, M. The Mechanisms of Sleep Function and Regulation for Health and Cognitive Performance. Brain Sci. 2023 , 13 , 1680. https://doi.org/10.3390/brainsci13121680

Fabbri M. The Mechanisms of Sleep Function and Regulation for Health and Cognitive Performance. Brain Sciences . 2023; 13(12):1680. https://doi.org/10.3390/brainsci13121680

Fabbri, Marco. 2023. "The Mechanisms of Sleep Function and Regulation for Health and Cognitive Performance" Brain Sciences 13, no. 12: 1680. https://doi.org/10.3390/brainsci13121680

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The Importance of Sleep by Kealey

Kealeyof Logan 's entry into Varsity Tutor's July 2017 scholarship contest

The Importance of Sleep by Kealey - July 2017 Scholarship Essay

Sleep is one of the most important aspects of our lives. For many, sleep is too often undervalued. But when all's said and done, we should place sleep as a higher priority in our lives because it enhances our physical and cognitive performance, improves our memory, and supports survival mechanisms. Sleep provides cognitive and physical health benefits that allow the human body to function more properly. I personally perform better in all aspects of life if I receive adequate amounts of sleep. Because of this, I strive to be in bed by my set bedtime (no later than 10:30 pm). There are instances, specifically on the weekend that I stay up later. In contrast, my father does not get enough sleep. During my teenage years, he would consistently go to bed around 11 pm or midnight and wake up at either 3:00 or 4:00 am. The reality of the need for sleep finally sunk in when my dad was diagnosed with Pseudotumor cerebri, or swelling of the optic nerve. Other health problems escalated as an after effect. Although there are no known causes of this condition, the doctors suggested that inadequate amounts of sleep may have been a contributing factor. In findings reported by the National Institution of Health,sleep is necessary to heal and repair the body’s immune functions, regulate a healthy balance of hormones, and also aids in growth and development. Like my father, sometimes the suffering presents itself in extremities. But more often than not, little things such as the common cold or flu affect those that don’t get enough sleep more. Because sleep is individualized, a person must ensure they get adequate amounts of sleep for proper physical functioning on a daily basis. Not only does sleep affect our physical abilities, it can enhance our overall mental abilities. In general, humans function better when they get enough sleep. Dr. Ferraro and Dr. Genarro, two Italian sleep psychologists, suggest a direct correlation indicating that performance ability declines as the number of hours of sleep declines. During sleep the brain builds and strengthens neurological pathways. When not enough sleep occurs, a person increases their risk of developing mental illnesses such as depression. Thus, this evidence provides support for doctors and therapists who suggest sleep as a remedy, both to cure physical and cognitive illnesses. Sleep also affects our memory. Being able to remember, retain, and recall are the three “Rs” to memory. The human memory relies on sleep for the enhancement of these. Dr. Jan Born, and Dr. Ines Wilhelm, two German psychology professors, recently conducted a study to find the relationship between sleep and memory. Their research indicates that sleep helps convert implicit knowledge or patterns, into explicit knowledge that is retained in the brain. Memory consolidation cannot happen correctly without sleep. Born and Wilhelm also found that sleep improves long-term memory. They suggest that sleep could be the process in which newly encoded memory representations are redistributed to other neuron networks serving as long-term storage. When I practiced for piano competitions in high school and attempted to memorize a song, I often played it right before bed. The next day, I could recall the music better compared to practicing it in the early afternoon. Thus, sleep becomes a beneficiary factor for memory. Sleep is not an independent variable. In fact, although sleep is important, there are many other things that are necessary to having a well-balanced life. Culture, family, work, social life, and values all determine one’s way of living. Despite the situations that make up a person’s life, sleep deserves greater prioritization. Dr. Michael Colgan, a world-wide renowned research scientist relates, “Sleep could be considered more important than food in maintaining physical and cognitive health if water supply is sufficient.” Sleep acts as as a survival tool, when not put to use, it can cause serious work-related and life-threatening crises. In 2005, The National Sleep Foundation found about 60% of all drivers have driven drowsy, furthermore 100,000 car accidents are sleep related. This included 1550 deaths and 71,000 injuries. This lack of sleep is a weapon: the sleep deficient driver becomes the offender, and other drivers on the road become the victims. Detecting drowsy driving tends to be more difficult to detect than things such as seat belt usage or driving under the influence. But, sleep deprivation and fatigue make lapses of attention more likely to occur. Sleep is a major factor that potentially saves lives. Even with the productivity of our society, Americans need to place a greater importance on sleep. Sleep is beneficial to maintaining and improving our cognitive and physical performances, memory functions, and acts a survival mechanism. As Russell Foster put it “Sleep is the golden chain that ties all aspects of health [and life] together.” If we placed sleep as a greater importance in our society, there would be less accidents, injuries, illnesses, and overall greater happiness levels. Take the initiative and start today to get enough sleep; crawl into your pajamas, and snuggle on into your bed for a full night's sleep.

The importance of sleep for efficient thesis writing

Thesis writing is hard. And it is common for students at all levels to feel stressed during this phase. Prioritising sleep may sound counterintuitive. But there are very good (scientific!) reasons to prioritise sleep for efficient thesis writing.

Sleep deprivation among postgraduate students

Numerous studies have mapped sleep deprivation and low quality of sleep among university students in various contexts. And it is not too surprising: Following postgraduate studies is intense. And thesis writing is a tedious process.

Negative effects of sleep deprivation

Unfortunately, when sleep is sacrificed, our physical and mental health suffers as well. Some commentators call the inadequate sleep that large parts of society get a ‘sleep deprivation pandemic’ that is raging across the world, reducing our quality of life.

In general, sleep deprivation can have physical consequences such as a reduced functioning of one’s immune system, obesity, and high blood pressure. Even higher risk of death by traffic accidents due to drowsiness.

Cognitive capacities required for effective thesis writing

Impaired cognitive performance through sleep deprivation.

After having established the importance of cognitive capacities for thesis writing, here comes the shocking news: sleep is connected to all of them. And a lack of sleep can have a huge negative impact on your cognitive performance!

If you know that you struggle with sleeping (enough), no need to worry. The book is not depressing. Instead, it helps you to understand what affects sleep, and how to better take care of your sleep.

Sleep deprivation, anxiety and depression

There is, of course, much more at stake than just a lack of sleep. But prioritising sleep, especially during difficult periods of thesis writing, should be part of your mental health care.

Simple tips for PhD, master’s and bachelor’s tudents to sleep better

Carving out enough time to sleep is challenging. But remember that stopping to work on your thesis in the evening and making sure to sleep early will probably pay off, as you will function better cognitively the next morning. This is effective thesis writing.

Master Academia

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