Sleep Hygiene
OVERVIEW
Sleep hygiene is a method of therapy which involves helping someone develop good sleep habits and avoid behaviors that hinder quality sleep. Focusing primarily on the behavioral and environmental adjustments, sleep hygiene is one mode of cognitive behavioral therapy (CBT), helping foster sound sleep by identifying and replacing thoughts and behaviors that cause or worsen sleep problems.[1] This modality was originally developed for use in the treatment of mild to moderate insomnia;[2] it may help people who have primary insomnia as well as people with physical problems, such as chronic pain, or mental health disorders, such as depression and anxiety.[3]
A key benefit of utilizing sleep hygiene is its increased duration of efficacy due to the likely eradication the underlying cause(s) of sleep problems.[4] Additionally, this therapy does not have side effects experienced by many sleep medications nor does it carry the associated risks of dependency, polypharmacy, cognitive and psychomotor impairment. It is therefore an attractive option for patients with co-morbid conditions.[5]
Sleep hygiene may be promoted in the general population to improve sleep and overall health as education of this modality does not require the direct involvement of a clinician; it can therefore be widely disseminated to individuals who are not likely to seek medical treatment for sleep problems. Further, as a relatively inexpensive lifestyle intervention, sleep hygiene education could serve as a first-line intervention in a stepped-care model for adults who suffer from inadequate sleep but are not likely to qualify for, or seek, more substantial clinical treatment. As sleep hygiene recommendations can be easily disseminated via a variety of online media channels, access among populations increases.[6] Additionally, as sleep hygiene adaptations are often viewed as intuitive and appealing, particularly compared to other behavioral methods used to promote sleep, adherence has been found to be relatively high and increase over time (68-78%) compared to the other treatment methods.[7]
Given that multiple factors can contribute to insomnia, using a multi-component approach such as sleep hygiene enhances the likelihood that one or more of the treatment elements will target the factors contributing to a patient’s poor sleep.[8] Additionally, behavioral interventions have been shown to be effective for middle-aged and older adults and older caregivers, populations in which comorbid medical conditions are more likely (e.g. SDB, hypertension, cardiac disease).[9]
Clinical research has found that over two-thirds of patients with insomnia who utilized 2-4 personalized sleep hygiene recommendations reported continued benefits post one-month, with many[10] perceived benefits retained over one year. Additional studies implementing individualized sleep hygiene recommendations in medical patient populations have reported improvements in subjective sleep quality,[11] but not actigraphy-assessed sleep.[12]
Prevalence
Sleep problems are prevalent worldwide, ranging from acute to chronic forms of prolonged sleep onset latency (SOL), excessive wake after sleep onset (WASO), short total sleep time (TST), low sleep efficiency (SE), or poor sleep. Comparative estimates from a 2006 study suggested that over half (56%) of Americans suffered from sleep problems over the previous year, as compared to 31% of Western Europeans and 29% of Japanese.[13] In a similar survey of adults across 10 countries, 31.6% of participants were classified as having insomnia with an additional 17.5% of participants classifying with sub-threshold insomnia.[14]
According to the National Sleep Foundation, the average American adult gets 6.9 hours of sleep on weeknights and 7.5 hours on weekends. Approximately 70 million Americans sleep poorly, and for more than half, it's a long-term problem.[15] While most middle-aged people function best on seven to nine hours of sleep, primary importance is on the quality, not the quantity, of sleep one experiences. Sleep requirements change during the course of a lifetime; most children need more sleep, most older adults, less.
Those suffering from insomnia exhibited one or more of the following behaviors:
Difficulty falling asleep.
Waking up often during the night and having trouble going back to sleep.
Waking up too early in the morning.
Having sleep that is not refreshing.[16]
A lack of sleep leads to chronic fatigue, depleting one’s energy level, mood, health, work performance and quality of life.[17] Excessive daytime sleepiness characteristically results in functional impairment throughout the day.[18] Even in the short term, insufficient sleep lowers concentration levels as well as cognitive ability. Further, insufficient sleep lessens physical coordination leading to a higher likelihood of falling or having a road accident.[19] Chronic, long-term sleep disorders affect millions of Americans each year, leading to an estimated $16 billion in medical costs each year, plus indirect costs due to missed days of work, decreased productivity, and other work-related economic factors.[20]
A highly complex function, sleep is essential for health and life, providing rest and restoration for mind and body. Sleep is divided into two major phases: rapid eye movement (REM) sleep and non-rapid eye movement (non-REM) sleep. Those experiencing optimal sleep fall asleep quickly, usually within 15 minutes. Non-REM sleep transitions gradually from light sleep (Stage 1) to deep sleep (Stage 4). During non-REM sleep, the mind and circulatory system slow down as heart rate and blood pressure fall; breathing slows and steadies and muscles relax. Sleep then shifts into REM phase after about 45 to 60 minutes. Although the eyes remain closed, they move rapidly in all directions. In contrast, the limb muscles are completely limp and immobile. Breathing is very slow and may even pause briefly. The brain is activated during this phase; dreaming occurs only during REM sleep. Although the body is entirely relaxed, the heart rate and blood pressure fluctuate from low to high; the heart pumps less blood to the body but more to the brain. The sympathetic nervous system is active, stimulating production of the stress hormone adrenaline. After about 30 to 45 minutes, sleep shifts back from REM to the non-REM pattern. The two states continue to alternate, with four to six 90- to 110-minute cycles occurring during the course of a typical night's sleep.
Incredibly complex, the body responds to a 24-hour circadian rhythm, responding to cycles of light and darkness. Sleep-wake cycle and several other bodily functions cycling throughout a day. For example, normal body temperature is lowest at about 5 a.m., when it averages 97° F, and highest at about 5 p.m., when it averages 99.4° F. Similarly, sodium excretion and urine output are normally higher during the day than at night. Hormone levels fluctuate with cortisol secretion highest during the morning; testosterone production peaks in the morning, growth hormone at night. Further, melatonin produced by the brain's pineal gland during the night.[21] Disruptions in the body’s normal sleep-cycle can result in bouts of acute or chronic insomnia.
Chronic insomnia can have significant systemic health impacts, both raising the risk of certain health problems while making existing conditions worse.
The NIH and Harvard Health list several of these conditions, including[22,23]:
Breathing problems such as asthma
Heart problems such as arrhythmia, heart failure, coronary heart disease, and high blood pressure (raising the risk of heart attack and stroke.)
Mental health conditions such as anxiety, depression, and thoughts of suicide. Insomnia can also increase difficulty of maintaining treatment for a substance use disorder.
Pain. People who have chronic pain and insomnia may become more aware of, and distressed by, their pain.
Pregnancy complications such as increased pain during labor, preterm birth and low birth rate, and increased likelihood of required cesarean section.
Problems with your immune system. Immune issues can lead to inflammation as well as increase difficulty in fighting infections.
Problems with your metabolism. Sleep deprivation decreases levels of leptin, a satiety-promoting hormone, and boosts levels of ghrelin, an appetite-promoting hormone. This can raise the risk of overweight and obesity, metabolic syndrome, and diabetes.
While medications for co-morbid conditions may perpetuate insomnia, a chronic lack of sleep may actually worsen the following co-morbid conditions or intensify their symptoms:
Brain disorders, such as Alzheimer’s disease, dementia, epilepsy, Parkinson’s disease, and traumatic brain injuries
Chronic (long-term) pain
Heart and lung diseases, such as asthma and heart failure
Mental health conditions, such as anxiety, depression, substance use disorder, and post-traumatic stress disorder (PTSD)
Other sleep disorders, such as restless leg syndrome, sleep apnea, and circadian rhythm disorders
Other health conditions, such problems with digestion, problems with your thyroid hormones
COMPONENTS
Sleep hygiene therapy is comprised of the following behavioral modifications, to promote more efficacious sleep; it is most beneficial to adhere to as many recommendations as possible.
Avoid Caffeine, Alcohol, Nicotine, and Other Chemicals that Interfere with Sleep
Caffeine is the most widely used psychoactive substance in the world;[24] its stimulant properties are often used to promote alertness. On a molecular level, caffeine's alerting and sleep-disruptive effects are driven by adenosine receptors in the basal fore-brain and hypothalamus.[25,26]
Current sleep hygiene recommendations vary from complete abstinence to avoiding caffeine only in the afternoon or evening.[27] Consumption of caffeine within 7 hours of bedtime is not recommended as plasma levels of caffeine peak approximately 30 minutes after oral consumption, with the half-life of a single dose lasting 3-7 hours. Individuals experience differences in sensitivity, metabolism, and accumulation,[28,29] with the half-life of caffeine increasing with a patient’s age, resulting in longer activation in older adults.[30]
Previous clinical research examined the administration of 200 mg of caffeine early in the morning and its effect on polysomnographic (PSG) sleep characteristics in 9 healthy, young, male participants.[31] Though salivary caffeine levels were low by bedtime, results indicated reduced TST and SE, in conjunction with a shift from lower to higher electroencephalographic (EEG) frequencies during whole-night sleep, following morning caffeine compared to placebo.
Another study of 12 healthy young adults administered 400 mg of caffeine in the late afternoon and evening (i.e. within the half-life of caffeine), and found that doses ingested up to 6 hours before bedtime were associated with disturbances in both subjectively and objectively assessed sleep.[32] In a direct comparison of the effects of 0, 100, 200 and 300 mg of caffeine administered shortly before bedtime, only those who received 300 mg of caffeine showed significant sleep impairments in comparison to those who received 0 mg of caffeine.[33]
Comparing low to moderate doses of self- administered caffeine, a double-blind trial was conducted measuring the effects of one cup of caffeinated vs. decaffeinated coffee after dinner on self-reported sleep in individuals who identified themselves as caffeine-sensitive.[34] Results indicated several significant effects of caffeinated coffee sleep quality.
A study of habitual caffeine users utilized a cross-over design to test the impact of tea (37.5 or 75 mg of caffeine) and coffee (75 or 150 mg of caffeine) consumption on participants’ sleep. Subjects received one type of caffeinated beverage (or water) at 0900, 1300, 1700, and 2100 hours for one day with a six-day washout period between beverage conditions. Results indicated that, compared to water, caffeine consumption was associated with greater self-reported difficulty falling asleep and lower sleep quality after controlling for the previous night's sleep, though these effects were notable only for the highest caffeine condition (coffee with 150 mg caffeine). Significant effects were also observed for actigraphy-assessed TST. In comparison to no caffeine (water), low-dose caffeine conditions (tea with 37.5 or 75 mg caffeine, coffee with 75 mg caffeine) resulted in approximately 15 fewer minutes of actigraphic TST and high-dose caffeine (coffee with 150 mg caffeine) resulted in almost 45 fewer minutes of actigraphic TST. Individuals with a lower habitual caffeine intake were more sensitive to the sleep-disrupting effects of caffeine than individuals with a higher habitual caffeine intake.[35]
Nicotine promotes arousal and wakefulness, primarily through stimulation of cholinergic neurons in the basal forebrain.[36] Sleep hygiene recommendations suggest avoidance of nicotine (via cigarette smoking or administration via pill or patch) to promote better sleep.[37] Nicotine use has been found to be associated with increased SOL, decreased TST, more frequent early morning awakening and suppression of rapid eye movement (REM) sleep and slow-wave sleep (SWS).[38]
Although general physiological tolerance to nicotine develops quickly this does not appear to translate into tolerance for nicotine's sleep-disrupting effects. Whereas caffeine tolerance results in a lesser impact on sleep disturbance, data suggest that even after years of smoking, smokers experience significantly worse sleep than nonsmokers.[39]
In the early stages of smoking cessation, sleep complaints are very common as nicotine withdrawal often results in heightened arousal and cravings. Symptoms of withdrawal peak a few days after cessation and last for 3-4 weeks.[40] A trained therapist may help guide you through a nicotine cessation program to combat rebound smoking during peaks of withdrawal.
Alcohol consumption is commonly discouraged in sleep hygiene education, with recommendations ranging from complete abstinence to avoidance of excessive use just before bedtime.[41] The acute effects of alcohol administration on sleep in healthy individuals are consistent and well-documented. Alcohol administration near bedtime is associated with decreased SOL and increased SWS during the first part of the night. However, once the alcohol is metabolized within the first few hours of sleep, subsequent sleep becomes lighter with increases in Stage 1 and REM sleep and more arousals due to the impact of alcohol on several neurochemical systems (e.g. GABA and adenosine.)[42-44]
Studies in healthy adults have generally shown a dose-response relationship between the amount of alcohol consumed and sleep onset and depth, suggesting that higher doses of alcohol are associated with worse sleep.[45-47] Effects are typically smaller and less consistent at lower doses of alcohol, which suggests that occasional and light consumption (1-3 standard drinks)[48] may be less likely to disrupt sleep than moderate or heavy doses. However, two small-scale studies examined the effects of alcohol administration in middle-aged men, 6 hours before bedtime; although breath alcohol levels had reached zero by bedtime, the reported effects on PSG-assessed sleep were similar to those found with bedtime administration.[49,50] Recommendations regarding absolute amounts of alcohol, however, should consider the gender of the individual as data suggest women's blood alcohol levels are significantly higher than men's after consuming the same amount and type of alcohol.[51]
Turn Your Bedroom into a Sleep-Inducing Environment
A quiet, dark, and cool environment can help promote higher-quality sleep. To achieve such an environment, lower the volume of outside noise with earplugs or a "white noise" appliance. Use heavy curtains, blackout shades, or an eye mask to block light, which is a primary biologic cue to awaken.
Keep the temperature comfortably cool, between 60 and 75°F, and the room well-ventilated. And make sure your bedroom is equipped with a comfortable mattress and pillows.
It may help to limit your bedroom activities to sleep and sex only. Keeping computers, TVs, and work materials out of the room will strengthen the mental association between your bedroom and sleep.[52]
Noise is a primary source of sleep disturbance, and sleep hygiene recommendations frequently advise individuals to minimize noise in their sleeping environment. However, nocturnal noises within one's normal surroundings (e.g., local traffic, music, plumbing) have the potential to impact sleep, even if they are not consciously observed. In general, nocturnal noise increases number of arousals and results in lighter sleep (increased Stage 1 and 2 and/or suppressed SWS and REM sleep.[53,54] Research suggests that the relationship between noise and sleep is moderated by characteristics of the noise itself (e.g. continuity, type, relevance) and to individual differences in noise sensitivity.[55] Overall, clinical research has found both sound-reducing (e.g. ear plugs) and sound-masking (e.g. white noise) strategies have been shown to improve sleep.[56]
Establish a Soothing Pre-Sleep Routine
Ease the transition from wake time to sleep time with a period of relaxing activities an hour or so before bed. Take a bath (the rise, then fall in body temperature promotes drowsiness), read a book, or practice relaxation exercises. Avoid stressful, stimulating activities such as doing work or discussing emotional issues. Physically and psychologically stressful activities can cause the body to secrete the stress hormone cortisol, which is associated with increasing alertness.[57]
Stress can precipitate cognitive arousal (i.e., worry) and physiological arousal, which are both antithetical to problems with sleep initiation and maintenance, with numerous studies observing an association between psychosocial stress and sleep.[58,59] Psychological stress increases psychophysiological arousal which is thought to be a primary mechanism through which stress disrupts sleep, particularly when the arousal is present at bedtime. Cognitive pre-sleep arousal (i.e. rumination before bedtime) mediated the association between daily stressors and subjective sleep quality.[60] Further, exposure to acute anticipatory stress close to bedtime resulted in increased sympathetic arousal, wakefulness throughout the night and less restorative sleep as measured by PSG.[61] Designated worry time or writing a worry list well-before bedtime has been shown to reduce arousal associated with psychosocial stress complaints.[62]
Techniques known to reduce stress and arousal, such as relaxation and mindfulness-based stress reduction, have been examined in relation to sleep and stress management, and may be an effective recommendation to promote sleep. Borkovec and Fowles suggested that relaxation is not directly responsible for better sleep, but rather, relaxation is focused attention that is incompatible with cognitive arousal.[63] Additionally, mindfulness, which is described as focused attention on the present moment without judgment,[64] has been utilized to reduce stress in multiple populations[65] and has been associated with improved subjective sleep quality. Mindfulness training has also been found to successfully reduce pre-sleep arousal and worry in individuals with insomnia.[66]
Keep Your Internal Clock Set with a Consistent Sleep Schedule
Sleep hygiene recommendations often encourage regular bed- and/or wake-times to maximize the synchrony between physiological sleep drive, circadian rhythms, and the nocturnal sleep episode. Natural light keeps your internal clock on a healthy sleep-wake cycle, thus exposure to light upon awakening is beneficial, as is daytime exposure to bright light to promote alertness.[67]
Struggling to fall sleep just leads to frustration; which, in turn leads to heightened arousal. If sleep evades you for 20 minutes, or if you wake in the middle of the night and cannot fall back to sleep within roughly 20 minutes, it is recommended to leave the bedroom and do something relaxing, like reading or listening to music until you are tired enough to sleep. While you are out of bed, keep the lights dim; bright light can stimulate your internal clock. Only when you feel ready and able to sleep, return to bed.
Staring at a clock in your bedroom, either when you are trying to fall asleep or when you wake in the middle of the night, can actually increase stress, making it harder to fall asleep. If you find yourself continually looking at your clock, turn the face away from you. Further, if you perpetually check your phone for the time, it is best to move it away from reach.[68]
Homeostatic sleep drive and the circadian system work together to promote stable patterns of sleep and wakefulness.[69] Sleep duration and continuity are worsened when sleep is shifted earlier or delayed from one's habitual timing of sleep.[70] Studies of nonclinical adult populations have found that irregular sleep schedules are associated with greater daytime sleepiness[71] and worsen self-reported sleep quality.[72,73] However, as afore-mentioned, current clinical sleep medicine therapies (e.g. stimulus control, CBT-I) call for regularity in wake time but permit variability in bedtime as individuals are instructed not to go to bed until they are sleepy.[74]
Daytime napping has been found to disrupt the homeostatic sleep drive, thusly sleep hygiene recommendations often include the recommendation to avoid naps of greater than 30 minutes.[75] Research evidences short naps (< 30 minutes) are beneficial to cognitive performance, alertness, and mood,[76,77] However, particularly in older adults, daytime napping (longer than 30 minutes) is associated with more self-reported sleep problems[78] and greater actigraphy-assessed WASO and fragmentation and lower SE.[79]
Exercise Early
Regular exercise is a common sleep hygiene recommendation, with the caveat that exercise should be avoided within three hours of bedtime. Exercise improve sleep through its effects on body temperature, arousal, and/or adenosine levels.[80] Two meta-analyses found that acute exercise produces modest increases in PSG-assessed TST, NREM stage 2 sleep, SWS, and latency to REM sleep, as well as a small reduction in SOL.[81,82] In a study examining the effects of acute exercise on sleep in adults with insomnia, an acute bout of moderate-intensity aerobic exercise performed in the late afternoon substantially improved PSG- and diary-assessed SOL and TST on the subsequent night, whereas neither high-intensity aerobic exercise nor moderate- or high-intensity resistance exercise altered sleep compared to a baseline night.[83] Therefore, this evidence suggests that an acute bout of exercise is likely to result in a modest improvement in a subsequent night's sleep.
Studies focusing on the impact of exercise training (i.e., ≥ 4 weeks of exercise at a specific weekly dose) have found a moderate-sized improvement in subjective sleep quality.[84] Thus, for populations with and without sleep complaints, exercise training is associated with modest improvements in sleep.
The timing of exercise is another important factor that may impact sleep, as exercising too close to bedtime could increase physiological arousal and disrupt subsequent sleep. While it is plausible that exercising close to bedtime may improve sleep due to the acute body-heating, anxiolytic and antidepressant effects of exercise,[85] the effects of exercise on core body temperature may be especially important during the afternoon or evening, as sleep onset typically coincides with the rapid decline in body temperature.[86] According to a meta-analysis, exercising 4-8 h prior to bedtime has the most robust effects on subsequent sleep compared to all other times of day, including decreased PSG-assessed SOL and WASO.[87]
CONSIDERATIONS
It is important to note the complex interplay between behavioral and environmental patterns within the context of sleep hygiene, and that many factors may affect the prevalence, nature, and impact of sleep-disrupting behaviors (e.g., age, gender, genetic polymorphisms, education, comorbid health conditions, social or occupational demands). Modification of one sleep hygiene behavior may lead to unintended changes in other behaviors, some of which may be undesirable (e.g. the increase of caffeine consumption to combat daytime fatigue, following the cessation of napping.) Individuals attempting to improve their sleep with sleep hygiene recommendations should be made aware of the potential benefits and consequences of modifying multiple aspects of their behavior. Working under the guidance of a trained therapist can assist individuals in navigating the process of multi-behavioral change.[88]
Ultimately, modification of behaviors is a reasonable approach to sleep improvement efforts. However, should prominent conditions present (e.g. severe insomnia, obstructive sleep apnea, narcolepsy, restless leg syndrome, etc.) one will require additional forms of treatment under the care of a physician or trained therapist.
Contributed by: Jennifer (Ghahari) Smith, Ph.D.
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