Chronic sleep deprivation is a significant public health concern that creates costs for both the individual (e.g. increased risk of chronic disease [1-5] and automotive accidents [6-8], and decreased cognitive performance [5,7,9,10-13] and emotional wellbeing [7,14,15]) and society (e.g. economic burden [3,15,17,18]), many of which go unrecognized by the general population [8,16]. Americans have been progressively sleeping less over the course of the past 100+ years [19,20], and over 10% of Americans currently suffer from insomnia [17,21,22], which is a sleep disorder characterized by having chronic difficulty falling asleep and/or staying asleep . However, insomnia is not the sole cause of sleep deprivation, as there are plenty of individuals who have no problem falling asleep and staying asleep, but who still experience sleep deprivation due to poor lifestyle management and/or an abundance of responsibilities.
Historically, sleep researchers would only study the effects of 1 to 2 nights of total sleep deprivation (i.e. no sleep whatsoever) with very little focus on the effects of chronic partial sleep deprivation [24,25] (i.e. getting 6 or less hours of sleep per night, for several consecutive nights [7,26]). However, many contemporary sleep researchers have shifted focus onto the effects of chronic partial sleep deprivation, as it is much more common for individuals to sleep poorly for extended periods than it is for them to “pull all-nighters” . This article addresses the effects of both total and partial sleep deprivation.
Unfortunately, Americans are largely uninformed about the negative consequences of sleep deprivation [3,8,16], especially compared to other public health concerns such as obesity, heart disease, and type II diabetes. To bring things into perspective, fatal car accidents due to sleep deprivation occur at a similar or greater rate than fatal accidents caused by alcohol intoxication . Drunk driving is vilified by the public, yet the same attitude is hardly directed towards sleep-deprived driving. In fact, working excessive hours while sleep deprived (and subsequently commuting while sleep deprived) is often glorified because it is a trait of the “hard-working American” cultural archetype. Dawson and Reid (1997) found that being awake for 24 continuous hours causes hand-eye coordination impairments comparable to having a 0.10% blood alcohol level  (the legal threshold for drunk driving is 0.08% ). The same researchers also found that moderate levels of fatigue due to partial sleep deprivation can actually cause equal or greater hand-eye coordination impairments than a blood alcohol level associated with intoxication. In addition, work days missed due to insomnia occur at a similar rate to work days missed due to lung disease or diabetes [17,29]. These are just a few examples of the negative consequences of sleep deprivation, albeit powerful.
This article will first address the negative consequences of sleep deprivation in more detail, and then provide different methods of improving sleep quality.
The Negative Consequences of Sleep Deprivation
Sleep Deprivation and Vigilance
One of the most profound and thoroughly researched effects of sleep deprivation is impaired vigilance [7,8,11,24,25,27,30,31], and it’s probably the easiest to recognize and understand. It doesn’t take a rigid scientific experiment to convince most people that sleeping poorly will make your mind feel hazy, slow, and less focused. Vigilance is a sense of alertness, awareness, and wakefulness. Put into its most basic terms, vigilance is a perceptual quality that allows you to sense the external world accurately so that you can respond appropriately to it. When vigilance is impaired, it becomes difficult to accurately assess what is going on around you, increasing the likelihood of committing an error. Errors due to impaired vigilance can be as innocuous as accidentally putting your keys in the refrigerator, or as serious as getting into a car accident.
Sleep deprivation and vigilance have an inverse relationship; this means that the more sleep deprived you become, the less vigilant you become [7,25,27,30]. This relationship may seem obvious, but what is not obvious is that those who are chronically sleep deprived tend to lack the ability to accurately rate their own level of mental fatigue, resulting in a normalization of impaired vigilance . That is, individuals who are chronically sleep deprived tend not to feel sleepy even though they “function sleepy”. On one hand, this is an example of human adaptability. But on the other hand, this normalization of mental fatigue can be disastrous. Even mild-to-moderate sleep deprivation can significantly impair vigilance [24,27].
Sleep deprivation can be quite hazardous, as reduced vigilance increases the rate of errors that result in injury and fatality. As stated previously, fatal car accidents due to sleep deprivation occur at a similar or greater rate than fatal accidents due to alcohol intoxication, and this is primarily due to impaired or nonexistent vigilance (i.e. falling asleep at the wheel) when driving . In hospitals, extended physician shifts (24+ hours) increase the occurrence of medical errors that cause harm and death to patients . However, it should be noted that the ability to tolerate sleep deprivation varies between individuals , as some individuals are simply better than others at maintaining a healthy level of vigilance while being sleep deprived.
Sleep Deprivation and Slow Wave Sleep
As you sleep, your body progressively shifts through different stages of sleep, each of which has unique physiological characteristics. The sleep stages are referred to collectively as “sleep architecture”.
A basic outline of sleep architecture is as follows :
- Non-Rapid Eye Movement (NREM) Sleep
- Stage 1
- Stage 2
- Stage 3 (Slow Wave Sleep)
- Stage 4 (Slow Wave Sleep)
- Rapid Eye Movement (REM) Sleep
As NREM sleep progresses through its 4 stages, sleep becomes “deeper”. REM sleep, which is the sleep stage in which dreaming occurs , follows NREM sleep. Throughout the night, your body cycles through NREM and REM sleep repeatedly.
Sleep deprivation disrupts healthy sleep architecture, causing an increase in certain stages, and a decrease in others. One of the most harmful effects of sleep deprivation on sleep architecture is the reduction of time spent in stages 3 and 4 of NREM sleep, also known as “slow wave sleep” [5,10].
Slow wave sleep (SWS) involves particularly restorative physiological processes that play an important role in learning and memory consolidation [5,9,10,12,15,33], although SWS as a whole is not entirely understood . However, is it understood that sleep deprivation, and the consequential reduction of SWS, impairs one’s ability to learn new information and retain memories (particularly fact-based memories) [9,12]. The negative implications of impaired SWS are obvious, as learning and memory-retention are ubiquitous aspects of the human experience. There is also evidence to suggest that low amounts of SWS may impair parts of the brain associated with emotional and behavioral regulation, increasing a tendency towards impulsivity . Maintaining healthy sleep habits may be especially important for older adults, as SWS naturally decreases with age.
Sleep Deprivation and Pain
There appears to be a reciprocal relationship between sleep deprivation and pain sensitivity [35-38]. That is, those who are sleep deprived are more likely to experience pain, and those in pain are more likely to be sleep deprived. It is well understood that those with acute and chronic pain conditions tend to have disrupted sleep patterns, but there is emerging evidence suggesting that sleep deprivation, independent from other factors, may actually cause or contribute to pain . If sleep deprivation increases pain, and pain increases sleep deprivation, the stage is set for a vicious cycle. The question of “Does sleep deprivation increase pain?” is a relatively new and complex area of scientific investigation that has yielded conflicting evidence [35-37].
In one study, 40 hours of total sleep deprivation increased mechanical pain sensitivity (i.e. pain felt due to the application of external pressure on the surface of a body part), although the specific mechanisms for why this occurs is not fully understood . When the study-participants got full nights of recovery sleep, their pain sensitivity returned to normal. The reduction of pain sensitivity due to improved sleep quality has been corroborated by other researchers . In the management of chronic pain conditions, high quality sleep has been found to be an important therapeutic factor .
In a more recent study, sleep deprivation was found to significantly increase thermal pain sensitivity (i.e. pain felt due to heat exposure) without causing a general effect on the body’s somatosensory system (i.e. the part of the nervous system that is responsible for sensing touch, temperature, and body positioning) . This finding suggests that sleep deprivation specifically affects nociceptors (i.e. pain receptors); this is notable because it demonstrates that researchers are coming to a closer understanding of the specific physiological mechanisms that underlie the relationship between sleep deprivation and pain.
Sleep Deprivation and Stress, Chronic Disease, and Emotional Wellbeing
Stress may seem like an ambiguous concept, but being “stressed out” involves several specific physiological responses. When the body experiences stress, the sympathetic nervous system (SNS) activates and stress hormones are released into the blood stream, causing an increase in heart rate, respiratory rate, blood pressure, availability of usable energy, sensory sensitivity (e.g. vision and hearing), and threat perception. This collection of physiological responses is colloquially known as “the fight or flight” response. When the SNS stress response occurs repeatedly over a prolonged period of time, you have chronic stress.
Chronic Stress Increases the Risk of :
- Heart Attack
- Type II Diabetes
- Cardiovascular Disease
- Obesity [39-41]
- Anxiety Disorders
When the body is deprived of sleep, it experiences greater levels of stress (i.e. an increase in both SNS activity and stress hormones in the blood) [1,5,11]. Therefore, chronic sleep deprivation can lead to chronic stress. The consequences of chronic stress are severe, so the health implications of getting consistent high-quality sleep are tremendous.
Researchers that study the relationship between sleep deprivation and chronic disease have found that being underslept impairs endocrine, metabolic, and cardiac function, increasing the risk of type II diabetes [1,2], obesity , high blood pressure [1,4], and cardiovascular disease [1,4].
Chronic stress can also lead to insomnia. This is highly problematic, as it presents another vicious cycle (the other one being sleep deprivation & pain sensitivity). Being underslept increases stress levels, and higher stress levels make it more difficult to sleep . If gone unchecked, this positive feedback cycle will transform you into a quivering mass of stress that somewhat resembles a human (+1 for hyperbole) until the homeostatic drive for sleep becomes so powerful that you eventually get a full night of sleep. To add further insult to injury, being sleep deprived intensifies negative moods  and decreases your ability to cope with stress [14,15].
Sleep Deprivation and Gender Differences
Women appear to be less sensitive to the negative effects of sleep deprivation , but it is unclear whether women are able to better tolerate these effects, or if they just experience them to a lesser degree. The majority of car crashes due to sleep deprivation tend to involve younger men , and this may be because women are less sensitive to the negative effects of sleep deprivation. However, compared to men, women are more likely to experience pain disorders that interfere with sleep .
Improving Sleep Quality
Now that we know what can go wrong when humans experience sleep deprivation, the pertinent question is, “What can be done to improve sleep quality?” To understand how to answer this question, we will have to first understand the concept of sleep quality.
Sleep Quality can be broken down into several components:
- Sleep Onset Latency
- The amount of time that it takes you to initially fall asleep
- Nocturnal Awakening (Frequency & Duration)
- Frequency = the amount of times that you wake up in the middle of the night
- Duration = the amount of time that you are awake when you wake up in the middle of the night
- Terminal Awakening
- The final time that you wake up before getting out of bed
- Slow Wave Sleep
- Deep sleep stages that are particularly restorative
- Total Sleep Time
- The total amount of time that you spend sleeping
- Total Time in Bed
- The total amount of time that passes between initially lying down in bed at night and getting up from bed in the morning
- Sleep Efficiency
- The division of: [Total Sleep Time]/[Total Time in Bed]
To increase sleep quality, the goal is to improve all of the above factors. To optimize sleep quality, you will want to minimize sleep onset latency and nocturnal awakenings so that you can maximize slow wave sleep, total sleep time, and sleep efficiency, which will result in an effective use of your total time in bed, leaving you feeling fully rested after your terminal awakening. To be pragmatic, you’ll simply want to reduce sleep onset latency and nocturnal awakenings, as they are the most important factors of sleep quality.
The following sections of this article describe and compare different methods of improving sleep quality.
Improving Sleep Quality with Prescription Medication
Hypnotic drugs (e.g. benzodiazepines and z-drugs) are commonly prescribed to individuals suffering from insomnia , despite the fact that there are non-pharmacological interventions that are shown to be more effective in treating insomnia [23,43,44]. The use of prescription sleep aids is more common in America compared to other countries . Hypnotic drugs have been found to significantly increase total sleep time in individuals with insomnia, at least in the short term [23,44,46-48]. However, the effectiveness of hypnotic drugs comes with a price – negative side effects [23,42,46,47,49-53]. In addition, a fair amount of the scientific literature on the effectiveness of prescription sleep aids had involvement/funding from pharmaceutical companies and private sources, indicating a clear bias [42,47], which suggests that positive outcomes were likely over-represented and negative outcomes were under-represented.
Potential Negative Side Effects of Prescription Sleep Medication:
- Drowsiness [42,43,46,47,50,52,53]
- Tolerance 
- Dependency [42,47,49]
- Withdrawal Symptoms [42,47]
- Rebound Insomnia after Drug Discontinuation [23,47,52]
- Inhibited Natural Production of Melatonin* 
- Dizziness [46,47,52,53]
- Lightheadedness 
- Impaired Cognitive Function and Memory [52,53]
- Decreased Slow Wave Sleep** and REM Sleep 
- Headache [43,46,47,53]
- Nausea [43,46,47,53]
- Nightmares 
- Gastrointestinal Disturbances [46,53]
- Increased Risk of Falls and Motor Vehicle Crashes (in elderly)*** 
- Sleep-Driving and Sleep-Eating 
*Reduction in natural production of melatonin may partially explain why prescription sleep medication can lead to rebound insomnia, withdrawal, and dependency (more on melatonin later in this article).
**A decrease in Slow Wave Sleep (SWS) is a troublesome side effect. As stated previously, SWS involves particularly restorative physiological processes that play an important role in learning and memory consolidation [5,9,10,12,15,33]. Therefore, prescription sleep medication may improve total sleep time, but the quality of that sleep may be low. Also, impaired cognitive performance and memory, which are also side effects of sleep medication, may stem from reduced SWS.
*** The elderly appear to be particularly sensitive to the negative side effects of prescription sleep medication, especially in individuals with cognitive impairment and a high fall risk .
With all the possible side effects associated with prescription sleep medication, a relevant question to ask is, “Would I rather feel bad from being sleep deprived, or would I rather get a full night of sleep with medication, but then feel bad anyway?” Of course, the individual response to the negative effects of sleep medication is variable.
Despite the potential negative effects, prescription sleep aids can be useful for individuals who experience situational insomnia (i.e. insomnia due to time-zone shifts, sleeping in unfamiliar places, and sleeping in places where it is impossible to control environmental variables such as light, sound, and vibrations). With a specific and short-term application of sleep medication for situational insomnia, dependency & withdrawal is not likely to occur, and individuals will not be chronically subjected to negative side effects.
Improving Sleep Quality with Behavioral Therapies
Cognitive Behavioral Therapy
As stated in the previous section, there are methods of improving sleep that are more effective than prescription medication, the most prominent method being Cognitive Behavioral Therapy (CBT) [22,23,43,44]. CBT addresses the relationship between your thoughts, emotions, and behavior, and reveals how that relationship negatively affects your sleep patterns . Irwin et al. (2006) state that, "Cognitive therapy breaks dysfunctional beliefs and attitudes about sleep that lead to emotional distress and further sleep problems."  For example, an individual who has experienced regular insomnia may develop a negative association with the act of lying down in bed to go to sleep, so much so that simply being in bed triggers a stress response and feelings of anxiety. The stress and anxiety will consequently impair his ability to fall asleep, further engraining the negative association with his bed.
Relating this example to the description of cognitive therapy by Irwin et al. (2006), “Cognitive therapy breaks dysfunctional beliefs and attitudes about sleep that lead to emotional distress and further sleep problems":
- Dysfunctional beliefs/attitudes = the negative association with going to bed
- Emotional distress = the stress and anxiety that occurs due to the negative association with going to bed
- Further sleep problems = disrupted sleep patterns due to the stress and anxiety, which over time further engrains the negative association with going to bed
Going deeper into this example, let’s say that the individual originally developed insomnia due to psychological stress that was unrelated to sleeping. Then, through the vicious cycle of stress inciting sleep deprivation & sleep deprivation inciting stress, the individual developed a negative association with going to bed, which further perpetuated his sleep problems. Thus, the insomnia developed primarily from a psychological origin, indicating that some form of psychotherapy (in this case, CBT) would be the best treatment option.
A therapist specializing in sleep medicine CBT would be able to work with the individual in this example, helping him:
- Become aware of how his negative beliefs and emotions are disrupting his sleep
- Develop a new perspective that fosters positive beliefs and emotions surrounding sleep
- Adopt proactive behavioral strategies that will improve the quality of his sleep
This is essentially a process of personal empowerment, which is why CBT yields long-term improvements in sleep quality. Once you recognize how to manage your thoughts and behavior effectively to promote restful sleep, you will always have those skills at your disposal. The pharmacological treatment of insomnia only yields short-term benefits because it is a passive intervention that requires no effort or change on the part of the individual.
While CBT is effective for improving sleep quality, you will want to see a therapist who specializes in sleep medicine CBT in order to get the best results, as there are many kinds of CBT . To find a therapist certified in behavioral sleep medicine CBT, click here.
There are other behavioral therapies besides CBT that are effective, and they don’t necessarily require a therapist in order for them to be understood and utilized. Behavioral therapy focuses more on how certain behaviors (or habits) negatively affect your life, without necessarily including the cognitive component .
Sleep Restriction Therapy
The goal of Sleep Restriction Therapy (SRT) is to have the total sleep time be as close as possible to the total time spent in bed. This is done by adhering to a rigid wake-up time, regardless of how tired you may feel in the morning . The process of SRT can leave you feeling significantly fatigued in the short-term because you are intentionally getting up while being underslept . However, this short-term discomfort leads to long-term benefits, as being underslept will increase the homeostatic drive for sleep (i.e. the natural impulse for desiring sleep). By accumulating the need for sleep, in combination with waking up at a consistent daily time, you increase sleep quality* and fortify a healthy circadian rhythm (i.e. your body’s natural sleep pattern) [23,55].
*Reduced sleep onset latency, reduced nocturnal awakenings, and increased time spent in slow wave sleep.
Here’s an example of how SRT is utilized:
- A woman has a hard time going to sleep on weekdays, and has to arise at 5am in order to be on time for work.
- She goes to bed at 9:00pm, but doesn’t fall asleep until 10pm.
- She wakes up several times during the night, which adds up to a total of 1 hour of nocturnal wakefulness.
- She wakes up at 4:30am because she is anxiously anticipating the work day ahead of her, but she stays in bed until the alarm goes off at 5am.
- Her total time spent in bed is 8 hours (9pm to 5am), but her total sleep time is 5.5 hours (1 hour to initially fall asleep + 1 hour of nocturnal wakefulness + terminal awakening 0.5 hours before her alarm goes off).
- For weekdays, her sleep efficiency = [5.5 total hours slept]/[8 total hours in bed] = ~70% (not good)
- On the weekend, she sleeps in late until 10am in order to recover from the accumulated sleep deprivation she experienced throughout the week.
- Then the weekdays arrive again, and she continues to sleep poorly in the fashion outlined above.
In this example, the woman swings from being underslept on weekdays to being overslept on the weekends by making extreme changes to her wake-up time (4:30am to 10am). This “consistent inconsistency” of her sleep pattern destabilizes her natural circadian rhythm, which is one of the reasons why she has such a hard time sleeping well on the weekdays.
The woman begins SRT. On the weekend, she no longer wakes up at 10am, but adheres to a consistent wake-up time of 5am. She trudges through the necessary fatigue for the first couple weeks, but over time, her sleep quality drastically improves, and she feels consistently well rested.
After a few months of SRT, here is the woman’s sleep pattern:
- She goes to bed at 9pm, and falls asleep at 9:30pm.
- She wakes up a few times during the night, but falls back to sleep relatively quickly, accumulating a total nocturnal wakefulness of 30 minutes.
- She sleeps deeply until her alarm goes off at 5am.
- Her total time spent in bed is 8 hours (9pm to 5am), and her total sleep time is 7 hours (0.5 hours to initially fall asleep + 0.25 hours of nocturnal wakefulness).
- Her sleep efficiency = [7 total hours slept]/[8 total hours in bed] = ~90% (much improved from ~70% before SRT).
Essentially, SRT exploits the effects of sleep deprivation in a therapeutic way in order to improve sleep quality and fortify a healthy circadian rhythm. The success of SRT is dependent on the individual’s consistency in adhering to a rigid wake-up time. One important note on SRT: napping is highly discouraged because it will decrease the natural sleep impulse felt at night, making it more difficult to fall asleep [55,56].
For a brief primer on SRT, click here.
Stimulus Control Therapy
According to Irwin et al. (2006), the goal of Stimulus Control Therapy (SCT) is to “help individuals renew the association of bed and bedtime stimuli with sleep rather than sleep disruption.”  For example, if you sit in your bed to make business calls, you will start to associate your bed with stressful tasks that require a high cognitive output. Over time, this behavior can interfere with your sleep because you are likely to revisit the stressful mental state associated with business calls when lying in bed at night.
Jacobs (2004) explains the basic protocol of SCT :
“Stimulus control techniques were designed to teach participants to associate the bed and bedtime with sleep as opposed to frustrating wakefulness and “trying” to sleep. Participants were instructed to (1) use the bedroom primarily for sleep and sex; (2) go to bed only when drowsy; (3) if unable to fall asleep within 20 to 30 minutes, get out of bed and go to another room to engage in a quiet, relaxing activity until drowsy; and (4) repeat this step as often as necessary and use for middle-of-the-night awakenings.”
SCT helps the individual develop a positive relationship with the bedroom in order to minimize stress and maximize sleep quality.
Summary of Behavioral Therapies
SRT and SCT are often used in conjunction with CBT to optimize improvements in sleep quality . Despite their effectiveness, behavioral therapies are not widely used in the treatment of sleep disorders because medical professionals often don’t refer patients to them . Unfortunately, the majority of medical professionals and patients are unaware of the effectiveness of CBT and other behavioral therapies [16,23,52].
The following table compares behavioral therapies with pharmacological sleep aids:
Behavioral therapies are effective because unhealthy behaviors are often the cause of poor sleep in the first place. CBT is used to identify negative thoughts, beliefs, and emotions that lead to unhealthy behaviors surrounding sleep. SRT is used to reverse the adverse effects of having an inconsistent sleep schedule, and SCT is used to reverse the adverse effects of regularly engaging in stressful/stimulating activities in the bedroom.
Here are some examples of how unhealthy behaviors can lead to poor health outcomes:
Note that the primary method for restoring health in all of the above examples is behavioral. More often than not, behavior is the most important factor to consider when improving one’s health.
Improving Sleep Quality with Sleep Hygiene
Sleep hygiene is a collection of behavioral and environmental guidelines that can improve sleep quality [26,45,57-61]. The guidelines are split into two basic groups:
- What to do to encourage quality sleep
- Behavioral example: exercise earlier in the day to increase fatigue at night, which will facilitate deeper sleep and a shorter sleep onset latency
- Environmental example: use a white noise machine and ear plugs at night to drown out uncontrollable ambient sounds that may be disruptive, such as noise from neighbors and passing cars
- What to avoid to encourage quality sleep
- Behavioral example: avoid consuming caffeine in the hours leading up to bed, as caffeine causes the release of stress hormones that can interfere with falling asleep
- Environmental example: avoid sleeping in a room that is lit brightly, as exposure to bright light can inhibit the body’s release of melatonin (a hormone that causes sleepiness) [62,63]
Individuals with insomnia tend to have poor sleep hygiene [59,60]. If you have insomnia and are trying to improve your sleep quality, sleep hygiene is a great place to start. Think of sleep hygiene as the first line of defense against insomnia, as it involves putting commonsense considerations into practice. Sleep hygiene can be effective on its own, but it is best used in conjunction with behavioral therapies such as CBT, SRT, and SCT . While sleep hygiene is similar to behavioral therapy, it is not a specific protocoled therapy. Sleep hygiene practices can be used on your own without the guidance of a therapist.
Out of all the sleep hygiene guidelines, one is of particular importance – the avoidance of bright light at night. Exposure to bright light at night can significantly disrupt the body’s circadian rhythm [64,65]. Environmental light acts as a “zeitgeber”, that is, an environmental stimulus that synchronizes the body’s circadian rhythm to the light/dark pattern of the 24 hour day . The zeitgeber of light is a powerful evolutionary mechanism that harmonizes the body’s function (i.e. sleep/wake cycle) with the earth’s function (i.e. axial rotation and orbit around the sun) . In simpler terms, when you are exposed to sunlight, you become wakeful, and when the sun goes down, you become sleepy.
However, with modern technology, humans can be exposed to bright light no matter the time of day, causing a disruption of the circadian rhythm. When the eyes are exposed to bright light when it is normally dark, the body shifts to a state that is more wakeful, vigilant, and energetic. In addition, exposure to bright light at night decreases the nocturnal secretion of melatonin [62,63], which is a hormone that makes you feel sleepy. So if you are having a hard time falling asleep at night, limit exposure to bright light in the hours leading up to bed, otherwise you are behaving in a way that goes against hundreds of thousands of years of evolution.
The following tables offer a comprehensive list of sleep hygiene variables.
The table below is a list of things to do [Stepanski & Wyatt, 2003]:
The table below is a list of things to avoid [Stepanski & Wyatt, 2003]:
Improving Sleep Quality with Meditation
The effect of meditation on sleep is a relatively new subject of scientific inquiry, but there is growing evidence suggesting that meditating can improve factors of sleep quality (e.g. shorter sleep onset latency, reduced nocturnal awakenings, and increased time spent in slow wave sleep) [66-71]. In addition to improving sleep quality, meditation has also been found to be effective in mitigating some of the negative consequences of sleep deprivation (e.g. impaired reaction time, fatigue, depression, decreased ability to cope with stress, and increased inflammatory biomarkers [67,70,72].
“In its simplest form, meditation is a practice of quietly observing the present moment. The “present moment” refers to both the outer world of sensory experience (e.g. sights, smells, body sensations), as well as the inner world of the mind (e.g. thoughts, beliefs, emotions). Meditation is not inherently religious; it does not require one to subscribe to a specific set of beliefs. There are many forms of meditation, but most focus on the breath as a way to anchor one’s conscious attention to the present moment.” 
Meditation helps improve sleep quality in two primary ways:
- Meditation helps decrease sympathetic nervous system (SNS) activity. Remember, the SNS is responsible for the “fight or flight” stress response. Chronic SNS activity impairs sleep quality. Therefore, calming the SNS through meditation can improve sleep quality.
- Meditation increases awareness of internal psychological processes (i.e. thoughts, beliefs, and emotions), helping you recognize mental patterns that lead to stress. By recognizing these stress-inducing patterns, you are better able to address them, helping you reduce stress, and therefore improve sleep quality.
Essentially, meditation improves sleep quality because it is an effective way to manage stress. Chronic stress can severely reduce sleep quality , so stress management is paramount when trying to improve sleep quality.
Meditation helps manage stress by:
- Increasing internal awareness so that one can recognize negative thoughts and feelings that lead to a stress response 
- Decreasing negative thinking [75-78]
- Improving mood 
- Increasing the ability to cope with anxiety 
- Reducing SNS activity and increasing PNS activity [81-83]
- Increasing heart rate variability (an indicator of the body’s ability to adapt to stress) [75,84,85]
In addition to helping manage stress, meditation can actually alter your sleep architecture by increasing the time spent in slow wave sleep (i.e. highly restorative deep sleep stages) and REM sleep [68,69,71]. This fact is especially pertinent for older adults who sleep poorly, as slow wave sleep naturally decreases with age .
In certain cases, meditation was found to be more effective than sleep hygiene , and some sleep researchers have asserted that meditation may be a better choice than CBT because it is more accessible (i.e. it doesn’t require a therapist, and it’s free) . Meditation, like CBT, can elicit long-lasting benefits to sleep quality because it empowers the individual to manage their stresses through an increased awareness of negative thoughts and behaviors . However, you don’t have to use meditation at the exclusion of other sleep improvement methods. Aspects of CBT, SRT, SCT, sleep hygiene, and meditation can be used in conjunction with each other, in a personalized way, to reap the greatest benefits in sleep quality.
Improving Sleep Quality with Melatonin
Melatonin is a hormone that is produced and secreted by the pineal gland [49,86], and there is evidence to suggest that it plays a powerful role in regulating the body’s circadian rhythm [49,62,87]. When melatonin is released into the blood stream, the body is cued that it is “biological night” and feelings of sleepiness start to occur [62,87]. Melatonin does not cause the body to suddenly fall asleep, but it quickens the transition of wakefulness to sleep [86,87].
Melatonin can also be found outside of the body, as it is easily synthesized in labs. Synthetic melatonin, which causes the same physiological effect on the body as its natural counterpart , is a popular over-the-counter sleep aid [49,62] that is available in many different forms:
- Rapid Release Pill
- Time Release Pill
- Dissolvable Tablet
Melatonin supplementation has been found to be an effective method of improving sleep quality, although dosage-timing appears to be a significant factor in its effectiveness [49,50,62,86,88,89]. While product labels often suggest consuming melatonin about 30-60 minutes before bed, current experimental evidence shows that it is actually most effective to take it in the early evening [50,88,89]. In a study that found melatonin to be as effective as prescription sleep medication, taking a dose right before bed had no effect on sleep quality, but a dose taken in the early evening elicited a profound improvement in sleep quality . There is conflicting evidence on the effectiveness of melatonin as a sleep aid , and sensitivity to dosage-timing may partially explain why.
Relatively small doses (i.e. 0.3 to 1.0 mg) of melatonin can improve sleep quality [50,86,88,89], but keep in mind that the timing of the dosage may be much more important than the quantity of the dosage . The dosages found in over-the-counter melatonin supplements tend to be much greater than the dosages found to be effective in scientific studies (up to 10 mg compared to ~1mg, respectively). While melatonin has a relatively low bioavailability (i.e. a significant percentage of ingested melatonin does not get absorbed into the blood) , dosages exceeding 1.0 mg do not appear to be necessary.
By consuming melatonin during a time when your body doesn’t naturally release it (i.e. the early evening), the concentration of melatonin in your blood increases to a level that would normally occur when your body does naturally release it (i.e. around the time leading up to bed). By increasing your melatonin levels through the evening with supplementation, you can cause an overlap with your body’s natural release of melatonin at night, so that you have a continuous concentration of melatonin in the blood from early evening to night. It is theorized that this overlap of exogenous (i.e. synthetic) melatonin with endogenous (i.e. the body’s own) melatonin can cause a phase advance (i.e. the body shifts to an earlier natural bed time), thus improving the ability to fall asleep .
The graph below demonstrates the general hypothesized concept behind the supplemented & natural melatonin overlap that causes an earlier natural bedtime.
In contrast, if you supplement with melatonin right before bed, as is commonly suggested on product labels, your body likely already has a relatively strong concentration of melatonin in the blood, so exogenous melatonin may have a negligible effect (more is not necessarily better). However, for those who have abnormally low levels of melatonin at night, which could result from a variety of reasons, supplementing with melatonin right before bed could be effective in improving sleep quality.
It is important to remember that melatonin facilitates sleep, but does not cause it [86,87]. There is no scientific consensus on whether or not melatonin is an effective sleep aid for the general population [49,62], as there is large variability between individuals (i.e. some experience significant improvements in sleep quality, and others experience little to no benefits) . For melatonin to work most effectively, you will want to follow sleep hygiene guidelines, such as engaging in relaxing activities and avoiding bright light in the time leading up to bed [62,86]. Also, the dosages and timing of melatonin can be experimented with to see what works best for you. As a general rule, start conservatively with dosages, and never exceed the usage directions printed on the product labels.
Melatonin is a valuable supplement for those that it works for, as it is much cheaper and more accessible than prescription sleep aids (e.g. benzodiazepines and z-drugs) , but without the laundry list of negative side effects . In one study, melatonin was actually found to be as effective as prescription sleep aids .
Melatonin supplementation is particularly relevant for:
- Blind individuals whose circadian rhythm cannot be anchored by the light/dark cycle of the 24 hour day .
- Individuals traveling across time zones who need to calibrate their circadian rhythm to the new time zone (in this case there is dissonance between biological night and geographical night, aka “jet lag”) [49,87].
- Night shift workers who sleep during the day .
- Individuals who live near the poles and as a result do not experience the same light/dark cycle that most humans do .
- Individuals who work indoors without windows and/or areas with dim lighting .
- Individuals with insomnia .
The goal of this article was to explain the negative consequences of sleep deprivation and describe different methods that can improve sleep quality.
Summary of the Negative Consequences of Sleep Deprivation
- Costs to the Individual
- Reduced Vigilance [7,8,11,24,25,27,30,31]
- Decreased Slow Wave Sleep (resulting in impairments in learning and memory) [5,9,10,12,15,33]
- Increased Sensitivity to Pain [35-38]
- Increased Stress [1,5,11]
- Increased Risk of Chronic Disease [1-5]
- Decreased Emotional Wellbeing [7,14,15]
- Costs to Society
- Economic Burden [3,16-18]
- Reduced Traffic Safety [6-8]
- Decreased Performance of Healthcare Professionals (resulting in patient harm and death) 
- Summary of the Methods that can Improve Sleep Quality
- Prescription Sleep Medication* [23,44,46-48]
- Cognitive Behavioral Therapy (CBT) [22,23,43,44]
- Sleep Restriction Therapy (SRT) [23,55]
- Stimulus Control Therapy (SCT) [22,23]
- Sleep Hygiene [26,45,57-61]
- Meditation [66-71]
- Melatonin Supplementation [49,50,62,86,88,89]
*The use of prescription sleep medication carries many potential negative side effects. [23,42,43,46,47,49,50,52,53]
Remember that you do not have to limit yourself to using just one of the above methods. Any combination of sleep improvement methods can be utilized. Individual responses will vary between the methods, so experiment with them to see what works best for you. Some may experience significant benefits with daily meditation, and others may not. Perhaps following sleep hygiene guidelines in conjunction with melatonin supplementation will give you great results. Depending on your lifestyle, some methods may be more pragmatic than others. If you regularly sleep poorly, it’s definitely worth the time to investigate these different methods of improving sleep.
I will close with a note on American culture:
Many Americans are forced to sacrifice sleep, and therefore their health, in order to fulfill responsibilities associated with work, family, school, and social circles. Despite the promises that advanced technology will bring us more leisure time, people are sleeping less now than they were 100 years ago [19,20]. The relationship between human function and advanced technology is highly complex, and many of its long-term consequences, both positive and negative, are unforeseeable. Advanced technology, combined with cultural values that prioritize economic productivity above all else, is a recipe for poor health. Sleep is a fundamental biological process that is necessary for healthy living. If sleep were not essential, humans would not have evolved to spend roughly 8 hours a day doing it. The fact that so many individuals are unaware of the importance of sleep demonstrates how unhealthy our cultural values are, and how detached we are from the intuitive sense of what our bodies need.
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