INTRODUCTION — A sufficient amount of sleep is essential for optimal physical health, immune function, mental health, and cognition. Insufficient sleep is a public health problem: nearly 30 percent of adults in the United States report sleeping six or fewer hours per day, and rates are even higher among younger adults and individuals with low socioeconomic status. Short sleep duration has been associated with a variety of adverse health outcomes, including cardiovascular disease, obesity, and all-cause mortality. (See "Insufficient sleep: Definition, epidemiology, and adverse outcomes".)
Insufficient sleep is only one of many causes of daytime sleepiness. This topic reviews the evaluation and management of insufficient sleep in otherwise healthy adults. An approach to the evaluation of excessive daytime sleepiness is presented separately. (See "Approach to the patient with excessive daytime sleepiness".)
SLEEP REQUIREMENTS — Consensus recommendations of the American Academy of Sleep Medicine and Sleep Research Society specify that adults aged 18 to 60 years should sleep seven or more hours per night on a regular basis for optimal sleep health [1]. Similarly, the National Sleep Foundation consensus report specifies that seven to nine hours is recommended for adults aged 18 to 64 years and seven to eight hours is recommended for those 65 years of age and older (figure 1) [2]. (See "Insufficient sleep: Definition, epidemiology, and adverse outcomes".)
If a person typically requires longer amounts of sleep, then even a seven- to nine-hour sleep duration may represent relatively insufficient sleep. Infants, children, and teenagers require substantially more sleep than adults [3]. (See "Assessment of sleep disorders in children", section on 'Sleep requirements'.)
DIAGNOSTIC CRITERIA — Formal diagnostic criteria for insufficient sleep syndrome (table 1) specify that a lack of adequate habitual sleep results in daytime sleepiness; associated symptoms may include irritability, decreased concentration, attention deficits, reduced vigilance, distractibility, poor motivation, fatigue, malaise, lack of energy, restlessness, and incoordination [4]. These and other adverse effects of insufficient sleep are reviewed separately. (See "Insufficient sleep: Definition, epidemiology, and adverse outcomes".)
EVALUATION — Insufficient sleep may go unrecognized by clinicians if patients are not asked about it as part of the routine history. In our experience, patients more commonly present with complaints of daytime fatigue, tiredness, sleepiness, drowsy driving, moodiness, irritability, and cognitive difficulties rather than specific concerns about insufficient sleep.
History — To assess sleep health, which includes both habitual sleep duration and sleep quality, patients should be asked about all of the following:
●Typical bedtime and rise time on weekdays and weekends.
●Presence of shift work.
●Quality of sleep: Is sleep refreshing? Is it difficult to get out of bed at the end of the sleep period? Are there awakenings during the sleep period? Poor quality sleep may be a clue to a specific sleep disorder such as:
•Chronic insomnia (see "Evaluation and diagnosis of insomnia in adults", section on 'Clinical features')
•Obstructive sleep apnea (see "Clinical presentation and diagnosis of obstructive sleep apnea in adults", section on 'Clinical features')
•Restless legs syndrome (see "Clinical features and diagnosis of restless legs syndrome and periodic limb movement disorder in adults", section on 'Clinical features')
●Presence and frequency of daytime naps.
●Presence of daytime fatigue or sleepiness that is functionally limiting. A complaint of sleepiness can be quantified using the Epworth Sleepiness Scale (ESS) (calculator 1) [5]. (See "Approach to the patient with excessive daytime sleepiness", section on 'Initial evaluation'.)
Contributing factors and mimics — Other causes of short sleep duration should be considered.
●Circadian rhythm disorders – Circadian rhythm disorders can result in insufficient sleep when school, work, family, or social obligations require an earlier wake up or later bedtime than is usual for the individual. For example, patients with delayed sleep-wake phase disorder often curtail sleep duration because they must wake early for school or work. (See "Delayed sleep-wake phase disorder", section on 'Clinical features'.)
●Concomitant illness – Medical, neurological, and mental disorders can result in long and/or short sleep duration.
●Medication effects – Medications or recreational drug use can cause short sleep duration.
●Sleep state misperception – Patients with insomnia can underestimate their actual sleep duration (sleep state misperception). This can be confirmed with sleep diaries and/or actigraphy.
●Normal variant – Some people are habitual short sleepers as a normal variant. They sleep <6 hours per night but do not report any daytime symptoms such as fatigue and deny problems with daytime function. (See "Insufficient sleep: Definition, epidemiology, and adverse outcomes", section on 'How much sleep do we need?'.)
Sleep diary — Sleep diaries provide valuable information about sleep patterns and practices to ensure patients are getting a sufficient amount of habitual sleep. They are inexpensive, readily available, and can be used to guide treatment recommendations and monitor response to therapy.
The diary should be kept for 7 to 14 consecutive days. A simple 24-hour log (form 1) or the more detailed consensus sleep diary (table 2A and table 2B) can be used [6]. The recorded period should reflect the patient's typical sleep pattern on both weekdays and weekends. Patients should avoid recording days during which they are ill or recovering from illness. For each night of sleep, patients should record best estimates about the previous night immediately upon waking in the morning [6]. When available, use of electronic diaries rather than paper-based tools may also help with adherence [7].
Ideally, sleep diaries should include the following elements:
●Time the patient gets into bed
●Time the patient fell asleep
●Number of times the patient awoke during the night
●Amount of time it took the patient to return back to sleep
●Time the patient awoke after nocturnal sleep period
●Time the patient gets out of bed for the day
●Number and duration of daytime naps
Additional information such as typical bedtime routine, what the patient did during awakenings at night, feelings about sleep quality, and caffeine, alcohol, or medication use may also be included. While there is no standard way of analyzing the sleep diary, average sleep time on weekdays and average sleep time on weekends can be extracted. Typically, additional information gleaned from sleep diaries will include sleep latency (time it took to fall asleep once lights are off; ideally 15 to 20 minutes [8]) and sleep efficiency (time asleep divided by time in bed x 100; normal ≥85 percent [9]). The difference between weekday and weekend sleep times and sleep duration can give an indication of "social jet lag." Significantly increased sleep time on weekends, compared with weekdays, can suggest significant chronic sleep deprivation due to work-related, social, or other weekday obligations.
Information obtained from sleep diaries may vary from objective sleep data obtained from actigraphy [10-12]. For example, one large study of 615 adults showed only modest correlation (r = 0.6) between sleep duration as measured by single-night sleep log versus actigraphy, and participants had a tendency to over-report habitual sleep duration [10]. Despite these limitations, sleep diaries remain a convenient, helpful, and commonly used tool. (See 'Actigraphy' below.)
Sleep questionnaires — The Sleep Timing Questionnaire (STQ) is a single administration instrument that generates measures of sleep that can approximate those obtained from a formal two-week sleep diary [13]. The STQ includes questions about habitual wake times and bedtimes on weekdays and weekends, similar to those obtained from a sleep diary (table 3). The questionnaire has reasonable test-retest reliability for bedtime and wake time but, like sleep diaries, correlates modestly with objective actigraphy data. The STQ may still be a useful tool to obtain habitual sleep duration when patient adherence with sleep diaries is a concern.
The Pittsburgh Sleep Quality Index (PSQI) [14], a self-report questionnaire composed of 19 items assessing sleep quality and disturbances over a one-month interval, is used to identify more general "poor sleepers." The PSQI (table 4A and table 4B) includes subscales on sleep duration and daytime dysfunction that can be useful to detect and follow insufficient sleep.
Actigraphy — Actigraphy allows for objective estimation of habitual sleep duration and some measures of sleep quality. While not required in all cases, it can be especially useful when patients are unable to reliably complete a sleep log or there are questions about the validity of the information provided. (See "Actigraphy in the evaluation of sleep disorders".)
Actigraphy records movements via a sensitive accelerometer, typically worn on the wrist, and estimates sleep parameters using a computerized algorithm. Actigraphy is used widely in research settings and increasingly in clinical settings, where use may be limited by lack of insurance coverage.
When available, actigraphy can be a very useful tool for estimating sleep patterns and sleep duration in healthy adults and children. Actigraphy is well validated against objective sleep times obtained from polysomnography (PSG) and provides useful estimates of total sleep time, sleep onset latency, the amount of wake after sleep onset, and sleep efficiency [15-17]. However, if movements in wake state are not robust, actigraphy can misinterpret the period as sleep [18]. Conversely, actigraphy can overestimate wake state and yield lower specificity for wake after sleep onset, a problem reported across studies in children [19].
Actigraphy is typically used for a one- to two-week duration. Some actigraphy devices also include light sensors, which can help quantify patients' light exposure at night or in the morning and verify bedtime. Such data can help identify patients with circadian sleep-wake rhythm disorders influenced by inappropriate light exposure. (See "Overview of circadian sleep-wake rhythm disorders".)
Supplemental sleep diaries are required during the actigraphy monitoring period. This may provide back-up data in case of device malfunction, differentiate wake but motionless periods misinterpreted as sleep on actigraphy, and provide an opportunity for the patient to explain uncharacteristic behaviors or situational context for arousals and napping.
Some actigraphy devices have an event marker that allows patients to record time in and out of bed. Patients should be instructed to use this function if available, as it can facilitate accurate interpretation of data downloaded from the actigraph. (See "Actigraphy in the evaluation of sleep disorders", section on 'Preparation'.)
Consumer wearable devices — Wearable sleep tracking devices are increasingly popular and are commonly worn on the wrist. Other wearables have been developed for the finger, head, and torso. "Nearable devices" are those that are placed near the individual during the sleep period (ie, under mattress, nightstand). Nearable devices track sleep using remote detection of physiological and behavioral signals.
Consumer sleep tracking devices offer an advantage of obtaining real-time data using wireless technology. They may also be lower cost compared with PSG and actigraphy,
Compared with a gold standard of PSG, the accuracy of the actigraphy data from consumer devices is variable and evolving. Studies have shown that consumer devices underestimate or overestimate minutes of sleep compared with PSG [20,21]. Some of the more recent sleep tracking devices have shown high sensitivity (ie, the proportion of PSG sleep epochs correctly detected as sleep by the device) but low to moderate specificity (ie, the proportion of PSG wake epochs correctly detected as wake by the device) [22].
A position statement from the American Academy of Sleep Medicine encourages clinicians to become familiar with the disadvantages and potential benefits of consumer sleep technologies, including wearable devices [23]. (See "Actigraphy in the evaluation of sleep disorders", section on 'Consumer wearable devices'.)
MANAGEMENT — Making a lifestyle change to obtain more sleep is very difficult for most individuals, and it is both crucial and challenging to get buy-in from patients, to a point that they feel motivated to change.
Counseling on lifestyle changes — Good sleep hygiene is critical to obtaining adequate, quality sleep on an ongoing basis [24]. We suggest counseling patients about all of the following (table 5):
●Sleep scheduling – Stick to a sleep schedule of the same bedtime and wake up time, even on the weekends. Consistency makes it much easier to fall asleep and wake easily.
●Bedtime routine – Practice a bedtime routine. While this is rarely assessed formally in research studies, one study incorporated a routine of personal care, lights out, and reduced sources of noise up to two hours before the desired sleep time as part of a multiphase sleep treatment intervention that effectively improved duration of sleep for a cohort of nursing home patients [25].
Wind down with quiet activities that may promote sleep, such as reading with a dim light. Avoid use of electronics at least 30 minutes before habitual bedtime and in the middle of the night if nocturnal awakenings occur. The blue light emitted from computer screens and handheld devices can suppress natural melatonin production, resulting in difficulty falling asleep; however, the exact duration of use and intensity of lighting that cause this effect are variable in the literature [26,27].
If you cannot sleep, do not look at a clock. Go into another room and do something relaxing until you feel drowsy enough to fall asleep again. Then return to bed.
●Napping – If you have trouble sleeping at night, avoid naps, especially in the late afternoon. However, short naps lasting approximately 20 minutes can help alleviate daytime fatigue, sleepiness, and even provide cognitive benefit [28,29]. Nap duration over 30 minutes is more likely than shorter nap duration to produce sleep inertia, a period of reduced alertness and cognitive performance after waking [30].
Naps are often necessary for shift workers to mitigate fatigue and improve alertness during work times [31]. (See "Sleep-wake disturbances in shift workers".)
●Exercise – Exercise daily. In one meta-analysis, regular exercise (defined variably across studies) was shown to have small beneficial effects of total sleep duration, small-to-medium beneficial effects on ability to fall asleep faster, and moderate beneficial effects on sleep quality [32].
●Sleep environment – Maintain a sleep environment conducive to sleep. The bedroom should be comfortably cool. In population studies, nocturnal environmental light and noise significantly impact sleep quality and quantity [33,34]. Use of blackout curtains, ear plugs, or sound machines may help promote an optimal sleep environment for individuals with sleep disruptions due to environmental stimuli.
Sleep on a comfortable mattress and pillows.
●Morning light – Regular bright light exposure in the mornings may help to maximize alertness and maintain a regular circadian rhythm. Studies in extreme latitudes where sunlight is minimal in the winter have found that an hour of exposure to white light in the morning helped subjects go to sleep earlier and wake earlier [35]. Exposure to blue light in the morning may have more robust effects on the stability of the circadian rhythm [36] and has been shown to improve daytime fatigue and sleepiness [37].
●Substance avoidance – Avoid cigarettes, caffeine, and heavy meals in the evening. While alcohol use does seem to reduce the time it takes to fall asleep, studies have reported that evening alcohol intake can cause more waking time or light sleep in the second half of the night and reduce self-reported sleep quality [38]. Evening nicotine is associated with lower sleep efficiency and more awake time during the night [39].
Referral to sleep medicine specialist — Referral to a clinician with sleep specialization is an option for patients who continue to have difficulty obtaining sufficient sleep despite the sleep hygiene advice above. Sleep medicine specialists can address a broad range of sleep disorders and sleep problems.
In particular, cognitive behavioral therapists specialized in sleep medicine work to restructure thoughts, emotions, and behaviors that contribute to sleep problems such as insomnia [40]. Self-regulation interventions such as mental imagery techniques have been shown to improve sleep-related behaviors and sleep patterns in adults [41]. (See "Cognitive behavioral therapy for insomnia in adults".)
Outcomes — Adverse health outcomes associated with insufficient sleep are numerous, including accidents and workplace errors, reduced quality of life, obesity, and increased cardiovascular risk. Interventions to improve sleep duration and reduce or reverse such outcomes are not well studied prospectively.
Early data are encouraging, however. In a novel randomized trial, 80 adults who were overweight and had habitual sleep less than 6.5 hours per night were randomly assigned to a sleep hygiene counseling session intended to help extend nightly time in bed to 8.5 hours or to continue their habitual sleep (control group) [42]. After two weeks, the intervention group had increased sleep by 1.2 hours per night compared with the control group. Those in the sleep extension group lowered their energy intake by 270 kcal/day and weight by 0.87 kg compared with controls. These results provide rationale for further study of sleep optimization as part of behavioral weight management strategies. (See "Obesity in adults: Behavioral therapy".)
SAFETY AND DRIVING — Patients with sleep insufficiency may be at risk for drowsy driving and fall-asleep crashes and should be appropriately counseled on prevention and countermeasures [43]. (See "Drowsy driving: Risks, evaluation, and management", section on 'Prevention and countermeasures'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Insomnia in adults" and "Society guideline links: Parasomnias, hypersomnias, and circadian rhythm disorders".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Sleep insufficiency (The Basics)" and "Patient education: Daytime sleepiness (The Basics)" and "Patient education: Insomnia (The Basics)")
●Beyond the Basics topics (see "Patient education: Insomnia (Beyond the Basics)")
Patients may also find useful information about health sleep habits from the National Sleep Foundation's site.
SUMMARY AND RECOMMENDATIONS
●Definition of adequate sleep – Adequate sleep duration is necessary for optimal daily performance and long-term health. Adults aged 18 to 60 years should sleep seven or more hours per night on a regular basis for optimal sleep health (figure 1). (See "Insufficient sleep: Definition, epidemiology, and adverse outcomes".)
●Criteria for insufficient sleep syndrome – Insufficient sleep syndrome is defined as a lack of adequate habitual sleep resulting in daytime sleepiness (table 1). Associated symptoms may include irritability, decreased concentration, attention deficits, reduced vigilance, distractibility, poor motivation, fatigue, malaise, lack of energy, restlessness, and incoordination. (See 'Diagnostic criteria' above.)
●Evaluation – Habitual sleep duration should be assessed in patients with concerns about daytime functioning and ideally in all patients as part of routine anticipatory guidance. The clinical history is generally sufficient to assess sleep duration and screen for additional problems with sleep that may suggest a specific sleep disorder. (See 'History' above and 'Contributing factors and mimics' above.)
Additional tools to obtain detailed and accurate habitual sleep information include sleep diaries (table 2A-B and form 1), sleep questionnaires (table 3 and table 4A-B), actigraphy, and some of the more recent consumer wearable sleep tracking devices. (See 'Sleep diary' above and 'Sleep questionnaires' above and 'Actigraphy' above and 'Consumer wearable devices' above.)
●Management – Sleep hygiene is the foundation of improving sleep duration (table 5). All patients should be counseled lifestyle changes conducive to obtaining adequate sleep on a regular basis. (See 'Counseling on lifestyle changes' above.)
Referral to a sleep medicine specialist or sleep cognitive behavioral therapist can be considered for patients who habitually obtain inadequate sleep and have daytime fatigue or sleepiness. (See 'Referral to sleep medicine specialist' above.)
●Safety and driving – Patients with sleep insufficiency may be at risk for drowsy driving and fall-asleep crashes and should be appropriately counseled on prevention and countermeasures. (See "Drowsy driving: Risks, evaluation, and management".)
