Everything You Need to Know About Sleep Deprivation
If sleep were a sports team, we’d describe it as perennially underrated. Even though everyone knows that sleep is important, it is frequently one of the first things to get bumped down on our list of priorities when life gets busy.
Shaving hours off of sleep for work, school, or social functions has become commonplace, and a huge percentage of Americans report getting less sleep than recommended. When left untreated, sleep disorders and other health problems take a toll on sleep quality as well. All tolled, perhaps as many as 35% of adults in the U.S. suffer from insomnia.
While most people may realize that there are consequences to not getting enough sleep, in many cases, it is “out of sight, out of mind.” Unfortunately, this approach sets the stage for serious problems that affect brain function, physical health, and emotional well-being.
This guide will set the record straight about sleep deprivation. It explains the causes and symptoms of sleep deprivation as well as its long-term health effects. It describes how sleep deprivation is diagnosed and outlines some of the potential treatments that can allow sleep to become a positive contributor to health.
What is Sleep Deprivation?
Sleep deprivation, also known as sleep insufficiency, is a condition in which a person’s poor sleep affects their health, awareness, and/or performance.
When hearing the term sleep deprivation, it is normal to first think about sleep quantity. For adults, the recommended amount of sleep is seven to eight hours. Children and teens need more sleep than adults, usually nine hours or more depending on their age.
Quantity of sleep is certainly important, but it’s not the end-all, be-all. Sleep quality is also vital, and this means that sleep is sound and consistent. Even people who get enough hours of total sleep may have sleep insufficiency if that sleep is fragmented by multiple awakenings during the course of the night. Sleep efficiency is the amount of time in bed that is actually spent sleeping, and the more efficient the sleep, the higher the sleep quality.
Getting enough hours of sleep that is uninterrupted allows the body to move through each of the four sleep stages. Those stages combine to form a full sleep cycle, ranging from light sleep to deep sleep to rapid eye movement (REM) sleep. Completing multiple cycles each night allows us to get truly beneficial and restorative sleep.
When a person doesn’t get enough hours of sleep and/or if their sleep is fragmented, it creates sleep insufficiency. This insufficiency can be acute or chronic. Acute sleep deprivation generally is experienced over a short timeframe, such as a day or two. If a person consistently fails to get enough quality sleep, it is considered to be chronic sleep deprivation, also known as sleep restriction. Both acute and chronic sleep insufficiency can create health risks.
Who is Affected by Sleep Deprivation?
Sleep deprivation affects people of all ages. Sleep is essential for children, but many of them suffer from sleeping problems. During adolescence and teenage years, sleep often becomes reduced when school start times come into conflict with natural changes to a teen’s preferred sleep times.
Young adults and people in middle age are no strangers to challenges for sleep. Some people carry over sleeping problems from their youth, and others may struggle with health conditions or lifestyle changes (including work and family obligations) that reduce their sleep quantity and quality.
Older adults also frequently experience significant sleep disruptions and grapple with sleep deprivation that affects them along with other co-existing health challenges.
What Are The Causes of Sleep Deprivation?
Acute and chronic sleep deprivation can happen for a huge range of reasons. They can be lifelong problems or something that arises seemingly out-of-the-blue. For some people, there may be more than one cause as multiple factors can contribute to sleeping problems.
The following sections introduce some of the most well-known and problematic causes of sleep deprivation.
In many cases, sleep problems are separated into two categories: primary and secondary. Secondary sleep problems are caused by something external to sleep. For example, if a person takes a medication that keeps them awake, their sleeping problems are considered to be secondary to the medication.
On the other hand, primary sleep disorders are directly tied to sleep patterns and by their nature involve reductions in sleep time and/or increases in sleep disruptions.
Because sleep is so complex and influenced by so many aspects of human biology, there are over 80 different sleep disorders. We won’t describe all of them here; instead, we’ll introduce some of the most common and impactful types.
Insomnia is a sleep disorder in which a person has a hard time falling asleep (sleep onset) or staying asleep until the time they would like to (sleep maintenance). Insomnia can be acute or chronic, and because it is such a broad disorder, can also be primary or secondary. It can occur alongside other sleep disorders, which can actually be the cause of insomnia.
Sleep apnea falls into a category of sleep disorders that may be described as sleep-disordered breathing (SDB). As the name implies, these are problems that relate to how effectively a person can breathe during the night.
In sleep apnea, during the night a person has frequent pauses in their breathing. These pauses are known as apneas. Apneas may be experienced as gasps or gulps for air, and they can cause frequent brief awakenings in the night.
There are two types of sleep apnea. Obstructive sleep apnea (OSA) is when a person has breathing problems because of a blockage in the airway in the throat. When the muscles and tissue in the back of the throat relax or become enlarged, they can block the airway and cause chronic snoring along with apneas. Central sleep apnea (CSA) is caused by faulty communication between the brain and the muscles that control breathing. A person can have both OSA and CSA at the same time, and this is called complex or mixed sleep apnea.
Sleep apnea is a serious disorder because it interferes with sleep quality and because it prevents the body from getting the regular supply of oxygen that it needs. As a result, there are serious and complex negative health consequences that can arise from both OSA and CSA.
In recent years, the diagnosis of OSA in particular has become increasingly common as more people become aware of this condition. Obesity increases the risk of OSA, so rising obesity rates may be pushing up the prevalence of OSA. There are wide-ranging figures available regarding the frequency of OSA, but the average of various estimates is that 17% of men and 22% of women are affected by this serious condition.
Restless Leg Syndrome
The primary symptom of Restless Leg Syndrome (RLS) is a strong urge to move the limbs when the body is at rest. Most often, this affects the legs. This urge can be extremely powerful and discomforting. It may even provoke feelings of tingling or numbness. Moving the legs can offer temporary relief, but in most cases, the feeling quickly returns.
RLS can make it extremely difficult to be comfortable in bed, and for this reason, it affects both sleep onset and sleep maintenance. People affected by RLS often also suffer from Periodic Limb Movement Disorder (PLMD), which is a condition marked by involuntary movements of the legs and/or arms during sleep.
Circadian Rhythm Sleep-Wake Disorders
Our body is governed by circadian rhythms, 24-hour cycles that promote the normal and healthy functioning of most bodily systems. These rhythms are largely controlled by the circadian pacemaker, a part of the brain, based on exposure to light. The most well-known circadian rhythm is for sleep, and it is intimately connected to the day-night cycle. It helps us be awake when it’s light out and sleepy when it’s dark.
Unfortunately, the body’s internal clock for sleep can become misaligned with the solar cycle. When that happens, it can result in one of several Circadian Rhythm Sleep-Wake Disorders (CRSWD). In Advanced Sleep-Wake Phase Disorder (ASWPD), a person’s internal clock pushes them to go to bed and wake up very early. In Delayed Sleep-Wake Phase Disorder (DSWPD), the opposite is the case: a person’s internal clock pushes them to stay up late at night and sleep in during the morning.
ASWPD and DSWPD are just two examples of these disorders. ASWPD is more common in adults while DSWPD tends to affect teens and young adults. In each case, a person’s preferred sleep schedule can easily come into conflict with their obligations (for school, work, family, or social life), leading them to have reduced sleep time and sleep deprivation.
Hypersomnia includes a range of conditions that are defined by excessive sleep and/or daytime sleepiness. While someone with insomnia may feel tired during the day, they often feel somewhat refreshed by napping. This isn’t the case for someone with hypersomnia. They may nap repeatedly during the day and still find no relief from their sleepiness.
One of the best-known manifestations of hypersomnia occurs as a result of narcolepsy. Narcolepsy is a neurological condition that entails having a misaligned sleep-wake cycle. People with narcolepsy suffer from bouts of extreme sleepiness and can be prone to involuntarily fall asleep without a moment’s notice during the day, including while doing other activities.
Another type of hypersomnia is called behaviorally induced insufficient sleep syndrome. This happens when a person chooses activities that lead them to have reduced sleep. The sleep deprivation is not intentional but happens as the result of conscious choices. This hypersomnia develops when these choices cause a person’s sleep to be reduced over a period of three months or more.
Parasomnias are a collection of conditions that are defined by abnormal behaviors during sleep. Examples of parasomnias include sleepwalking (somnambulism), night terrors, sleep paralysis (sleep atonia), Sleep-Related Eating Disorder, talking during sleep (somniloquy), and many others. They are often classified based on the stage of sleep during which they occur.
Often people who have parasomnias are unaware of these behaviors and only learn about them when told by a family member or someone that they live with. Parasomnias can lead to disrupted or reduced sleep, contributing to both acute and chronic sleep insufficiency.
Other Medical Conditions
Sleep deprivation can arise as a secondary effect of many health conditions. For example, people with mental health conditions like depression, bipolar disorder, anxiety disorder, and post-traumatic stress disorder (PTSD) often find that they have problems falling asleep or staying asleep. Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are neurodevelopmental disorders that can reduce sleep duration and quality.
People who suffer from pain, including back pain, hip pain, and arthritis, commonly find that it is hard to be comfortable enough to get quality, consistent sleep. Frequent nighttime urination, known as nocturia, can create fragmented sleep, especially in older adults. Cancer and its related health complications often cause fatigue and sleeping problems, and many other health conditions, including diabetes, cardiovascular problems, and lung diseases can all contribute to sleep insufficiency.
As we will discuss in more detail later in this guide, the relationship between sleep and many of these health problems is bidirectional. This means that these conditions can reduce sleep and that decreased sleep can contribute to these conditions. The unfortunate outcome is that people with many physical and mental health problems can find themselves in a frustrating downward cycle of disrupted sleep and worsening symptoms.
Some medications are known to have an effect on sleep. These can include both over-the-counter (OTC) drugs and prescription medications. Examples include drugs for high blood pressure, asthma, heart rhythm problems, cold symptoms, depression, hypothyroidism, and more. Some of these drugs make it harder to fall asleep at night while others can cause excessive daytime sleepiness.
Insufficient Time Devoted to Sleep
For some people, sleep deprivation is a result of an inadequate amount of time devoted to sleep. This can happen for many reasons including work obligations, social life, and school assignments. Treating sleep as a lower priority than other activities -- including other health-focused activities like exercise -- can obviously result in cutting down on the time apportioned each night for sleep.
Poor Sleep Hygiene
Some sleeping problems arise because of poor sleep hygiene. This means that a person’s sleep environment or lifestyle choices related to sleep detract from their ability to get quality rest.
People who have wildly inconsistent bedtimes or who frequently drink alcohol later in the evenings, for example, can find that these habits interfere with their sleep. Similarly, issues like excess noise or light in the bedroom can play a part in poor sleep hygiene.
Problems related to sleep hygiene can factor into challenges related to both sleep onset and sleep maintenance. In many cases, sleep hygiene issues occur at the same time as other health problems that affect sleep, creating a more significant barrier to sufficient restorative sleep.
What Are the Symptoms of Sleep Deprivation?
Both acute and chronic sleep deprivation can cause noticeable symptoms. Examples of the most common symptoms include:
- Observable disruption in sleep patterns: sleeping problems may be noticeable just form easily observed aspects of a person’s sleep patterns. For example, if a person frequently spends a large chunk of time tossing and turning before falling asleep, wakes up in the middle of the night without being able to get back to sleep, or arises in the morning well before they would like to, it can indicate the presence of a possible sleep disorder and sleep insufficiency.
- Excessive daytime sleepiness: people with reduced or fragmented sleep often feel fatigue and sleepiness during the day. They may find themselves clamoring for a nap or dozing off when they don’t want to, especially if they suffer from substantial sleep insufficiency.
- Mood changes: people who are sleep deprived are more likely to be irritable and easily frustrated. They may have heightened emotional reactivity, meaning that any emotional response can be exaggerated, making a person more prone to anger, outbursts, or withdrawal.
- Cognitive problems: without enough sleep, it is common to feel “in a fog,” with reduced mental acuity. This can mean slower reaction times, worsened learning and recall, and more difficulty staying focused.
The exact symptoms that any person shows can vary from day to day and can depend on their level of sleep deprivation, including whether it is acute or chronic. Some people may have better abilities to cope with or hide these symptoms than others.
Overall, though, a person with sleep insufficiency won’t feel well-rested during the day and will find that it has a discernible impact on one or more aspects of their health, mood, or performance.
What Are the Health Consequences of Sleep Deprivation?
Sleep is common to all mammals for a reason; it plays a critical biological role that enhances nearly all aspects of our health. Even though a complete explanation of the biology of sleep remains unknown, there is a widespread consensus that the consequences of sleep deprivation are profound.
At a big-picture level, research shows that good sleep helps people live longer and have a better quality of life. Epidemiological studies have consistently found that people who don’t get enough sleep have an increased risk of death from all causes. Beyond just reducing longevity, sleep insufficiency also has been shown to detract from happiness and quality of life.
These high-level metrics are enough to show that there are major negative consequences to lack of sleep. To provide a more detailed understanding, though, the following sections explain how poor sleep can create a host of problems for physical health, the brain, and emotional well-being.
Risk of Accidents
Lack of sleep increases the risk of all types of accidents. Because they can easily be life-threatening, car crashes are among the most concerning of these accidents. It is estimated that drowsy driving causes more than 72,000 collisions and perhaps as many as 6,000 deaths every year.
It is often said that drowsy driving is like drunk driving, and there is evidence to back this claim. People who stay awake for extended periods during the day begin to show effects that are comparable to drunkenness. One study found that being awake for more than 16 hours in a row can cause effects equivalent to those in a person with a blood-alcohol content (BAC) of .05% to .1%.
Serious accidents don’t just happen on the roads. They can occur in the home and workplace and can have major repercussions. Catastrophes at nuclear plants, major oil spills, and even the Challenger space shuttle explosion have been partly linked to sleep-related errors.
In addition to reduced psychomotor performance, people without enough sleep can be at higher risk of accidents because of worsened decision-making. These effects may be even greater in teens because the frontal lobe, the part of the brain that helps manage high-risk decisions, is still in the process of developing during the teenage years.
A sweeping health consequence of sleep deprivation is that it reduces the general functioning and effectiveness of the immune system. The normal production of immune cells, including cytokines, is affected by lack of sleep, with the net effect being a decreased immune response. This has even been seen with vaccines as they can be less efficacious when given under conditions of significant lack of sleep. Because the immune system provides an extensive network of defense against many types of illnesses, the impact of lack of sleep can be considerable, making it easier to get sick and harder to recuperate quickly.
Lack of sleep harms heart health in multiple ways. Sleep is a time that the body uses to repair blood vessels, so poor sleep can negatively affect circulation and the cardiovascular system. Studies have linked sleep insufficiency to higher levels of inflammation, including types of inflammation that can be deleterious to the heart. Cardiovascular problems are even more severe in people who have sleeping problems related to obstructive sleep apnea.
Metabolic Problems and Diabetes
Metabolism is the body’s process of generating and using energy, and proper metabolism requires good sleep. A major effect of sleep deprivation is that the body doesn’t process glucose as well as it should and has reduced insulin sensitivity. These factors can lead to an increase in blood sugar and a higher risk of Type 2 Diabetes.
Sleep deprivation has been shown to contribute to obesity and weight problems. Without adequate sleep, the hormones that regulate appetite become thrown off, and the body is less able to appropriately manage hunger according to actual calorie intake. The end result is that people who don’t get enough sleep tend to increase their calorie consumption and have decreased energy expenditure. When combined with metabolic changes induced by lack of sleep like those described in the previous section, this forms a perfect storm for weight gain.
The endocrine system controls hormones in the body, and for this system to operate at top efficiency, the body needs good sleep. We’ve already mentioned the hormones involved in metabolism and appetite, but the production of other hormones can also become thrown off by lack of sleep. For example, human growth hormone (HGH), which contributes to muscle mass and bone strength, is produced in higher amounts during sleep. HGH is also involved in proper regulation of metabolism.
Testosterone is another hormone that can have its production curtailed by sleep insufficiency. In one study, even just a week of sleep restriction in older adults found 10-15% reductions in testosterone levels. With normal aging, testosterone production declines at an average rate of 1-2% per year, so this decrease from sleep loss is significant. Like HGH, testosterone plays an important role in having strong bones and muscles, and it contributes to overall well-being.
Because both sleep and the endocrine system are biologically sophisticated, we don’t fully understand exactly how a lack of sleep impacts hormone production. But these few examples demonstrate that the potential implications are substantial.
Pain is one of the most common and significant health problems in the United States. Each year it affects more people than diabetes, cancer, and heart disease combined. When considering pain, we tend to think about it being caused by injuries and treated with drugs, and only rarely do we consider how it may be connected to sleep.
Researchers that have delved into this topic, though, have identified sleep as a factor that mediates the experience of pain. People who are in pain may have problems sleeping, but experts now believe that sleep has a greater effect on pain than pain does on sleep. Pain can be a negative consequence of sleep deprivation, and improving sleep may help the body recover and help a person’s psychological processing of pain.
Physical and Mental Development
From childhood through teenage years, sleep plays a critical role in promoting physical and mental development. Before reaching adulthood, people need more sleep in large part because it can facilitate full, healthy growth of muscles and bones. Neuroscientific research has increasingly found that adequate sleep is also essential for proper brain development.
Cognitive problems from a lack of sleep can arise over the very short term. As we mentioned previously, short sleep even over just a day can bring someone’s psychomotor skills to the level of someone who is cleared inebriated. This provides just a glimpse into the effects of lack of sleep on thinking.
Lack of sleep hurts all aspects of learning. It makes it harder to acquire new information, degrades memory, and slows down critical thinking. Healthy sleep is vital for the brain -- it allows the brain to clear out toxins, purge unnecessary information, and promote healthy communication between nerve cells. Any kind of studying, whether its learning facts or a new skill, is impaired by sleep deprivation.
Over the long-term, the memory problems associated with sleep deprivation become more worrisome. Lack of sleep has been connected to an elevated risk of memory loss, mild cognitive impairment (MCI), and dementia. Beta-amyloid is a protein that is associated with Alzheimer’s dementia, and research has discovered that lack of sleep may cause it to build up in the brain. Insufficient sleep and fragmented sleep may increase a person’s chances of developing dementia and exacerbate symptoms in people who already have the condition.
Mental Health Problems
Another negative effect of lack of sleep is that it can heighten the risk of developing mental health problems and can worsen symptoms in people who are already diagnosed with those conditions. Examples include depression, anxiety disorders (including PTSD), and bipolar disorder. People who are at higher risk of developing problems with anxiety, for example, are especially at risk of doing so if they don’t get enough sleep. Sleep plays an important enough role that some experts have even said that focusing on improving sleep may be considered a preventive mental health strategy.
For people who already suffer from these types of mental health challenges, a lack of sleep may make symptoms more intense. For example, episodes of disturbed sleep have been correlated with an increased risk of suicide in people with depression. With many mental health conditions, periods of disrupted sleep may portend a recurrence of symptoms after a period of remission.
Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are examples of neurodevelopmental disorders. These conditions affect the function of the brain and impact millions of people nationwide. Lack of sleep has been found to contribute to more significant symptoms and individual effects of both ADHD and ASD.
What Are the Societal Costs of Sleep Deprivation?
Sleep deprivation can have a huge burden on any individual, and because this problem affects so many people, it has escalating impacts when considered at the level of society as a whole.
The impact is felt in terms of overall well-being, which is difficult to quantify, but also in terms of other metrics like the need for medical care and economic productivity. Lack of sleep is believed to be responsible for hundreds of billions in additional healthcare costs each year in the U.S. alone. Reduced productivity, including from more missed days of work, is estimated to cost the U.S. economy $411 billion annually.
How is Sleep Deprivation Diagnosed?
It’s clear that sleep deprivation can have far-reaching consequences, and it should be considered a serious health issue. Like any major health problem, it is best addressed by working with a health professional.
Patients who have symptoms of sleep insufficiency can start by visiting their family doctor who will ask questions to better understand the situation. This may include questions about the nature of the symptoms, their severity, and how long they have been present. This discussion will likely also address a patient’s medical history and whether they are experiencing any other symptoms or dealing with any pre-existing health problems.
This clinical history is usually accompanied by a physical exam. These are a combined first step that allow the doctor to assess potential causes of sleep problems. To get additional information, the doctor may want to do some type of sleep tracking. This could include having the patient keep a sleep journal for a period of a week or more that documents their bedtime and wake-up time.
Sleep tracking can also be done with actigraphy. Actigraphy uses a device on the wrist to monitor motion. This motion-based data is then analyzed by an algorithm to calculate the time spent sleeping. Some sleep tracking devices may supplement actigraphy with data about heart rate or body temperature.
Other tests may be ordered depending on the situation. Tests may be used to diagnose certain causes and to rule them out. Polysomnography is a type of sleep testing done in a specialized laboratory where a patient stays overnight. It monitors multiple aspects of sleep, including breathing, and may be used to diagnose sleep apnea.
Other medical tests like blood tests, computed tomography (CT), magnetic resonance imagery (MRI), and others can be employed according to the judgment of the doctor about the most likely suspected causes of insufficient sleep.
How is Sleep Deprivation Treated?
At its most basic level, treatment for sleep insufficiency means getting more sleep and/or less fragmented sleep. However, the way to achieve that goal depends a great deal on any individual’s circumstances.
The following sections explain some elements of trying to treat sleep deprivation.
Don’t Accept Sleep Deprivation as Normal
As phrases like “I’ll sleep when I’m dead” indicate, many people normalize sleep deprivation and consider it to be a necessary part of their day-to-day life. This is particularly true of people with major family, work, or social demands.
When people with this mindset experience symptoms of sleep deprivation, they usually turn to coping strategies rather than actually devoting more time to sleep. Examples of coping strategies include:
- Increasing consumption of caffeine, energy drinks, or other stimulants
- “Powering through” and dealing with reduced levels of performance
- Squeezing naps into their day to try to counteract daytime sleepiness
- Attempting to “catch up” on sleep during weekends or vacations
None of these coping strategies are an actual treatment for sleep deprivation. While they may seem to help in the short-term, they can become a crutch. The body can also develop tolerance to stimulants like caffeine, forcing a person to consistently ramp up their consumption to try to keep away the symptoms of lack of sleep. Napping may cause a person to wake up even more groggy and in a fog.
Over the long-term, coping strategies do nothing to address the consequences of sleep deprivation. In fact, by masking the immediate impacts of sleep loss, they may create more serious problems in the future.
Treat Underlying Health Condition(s)
One of the most important ways to improve sleep is to treat other physical or mental health issues that are contributing to sleep problems. This therapy should be tailored to the specific condition and in some cases can be combined with steps to improve sleep as well.
For primary sleep disorders, treatments can play a huge role in addressing sleep deprivation. For example, positive airway pressure devices, including CPAP and BiPAP machines, can dramatically improve problems related to obstructive sleep apnea. Cognitive behavioral therapy for insomnia (CBT-I) can address many sleeping problems and can be designed to work in conjunction with other types of psychotherapy for mental health disorders that are related to sleep.
Improve Sleep Hygiene
Changes to sleep hygiene can be an important part of improving sleep. In some cases, these changes can themselves facilitate better sleep. In other cases, they may be combined with other therapies to create a holistic treatment plan for sleep insufficiency. Specific methods for stepping up your sleep hygiene are available in our list of 15 Tips to Improve Sleep Hygiene.