Sleep restores the body and brain, consolidates memory, supports immune function, and regulates mood and metabolism. Two processes control it: the circadian rhythm (a roughly 24-hour clock in the hypothalamus, set mainly by light and signaled by melatonin release in darkness) and sleep pressure that builds the longer a person is awake.

Sleep stages (current scoring combines the older stages 3 and 4 into a single N3 stage)

A cycle of NREM and REM lasts about 90 minutes, repeating 4–6 times a night; N3 dominates early in the night and REM later. After REM deprivation (for example, after stopping sedatives or alcohol), REM rebound causes vivid dreams.

Sleep need: adults need 7 hours or more per night; children 6–12 years need 9–12 hours and teens 13–18 years need 8–10 hours.

Changes with aging: total sleep time is similar or slightly less, but N3 and REM decrease, night awakenings increase, sleep efficiency falls, and the circadian rhythm shifts earlier (advanced sleep phase — sleepy early in the evening and waking early in the morning). Nocturia, pain, medications, and napping add to the problem.

Common sleep disorders

• Sleep history first — the simplest, noninvasive starting point: usual bedtime and wake time, time to fall asleep, awakenings, naps, perceived quality, daytime function, bedtime routines, environment, caffeine, alcohol, nicotine, screen use, medications, pain, nocturia, mood, stress, work schedule
• Sleep diary for 1–2 weeks
• Bed partner report — snoring, pauses in breathing, leg kicking, dream enactment
• Children: bedtime routine, fears or resistance, and snoring or breathing pauses (often enlarged tonsils and adenoids), reported by caregivers
• Physical signs of sleep loss: dark circles, yawning, irritability, poor concentration, slowed reactions
• OSA risk: neck circumference, obesity, hypertension, crowded airway; screening with STOP-Bang

Preparing for polysomnography: avoid caffeine and alcohol the afternoon and evening before (and naps that day); wash hair and avoid hair products so electrodes stick; bring usual nightwear and take usual medications unless told otherwise.

• Cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment for chronic insomnia — stimulus control, sleep restriction, cognitive therapy, relaxation, and sleep hygiene.
• OSA: weight loss, positional therapy, continuous positive airway pressure (CPAP), oral appliances, and in some cases surgery or hypoglossal nerve stimulation.
• Restless legs: check iron studies and replace iron if ferritin is low; avoid triggers (caffeine, alcohol, sedating antihistamines, some antidepressants); medications if needed.
• REM sleep behavior disorder: make the bedroom safe; medications per provider.

Drug safety for sleep medications

All hypnotics add to the central nervous system depression of alcohol and opioids — combining them can cause dangerous sedation and respiratory depression.

1. Safety first with hypnotics: assess sedation and respiratory status, use fall precautions, keep the bed low and the call light within reach, and help with nighttime toileting.
2. Create a sleep-promoting environment in hospital: dim lights at night and bright light during the day to support the circadian rhythm; reduce noise (alarm management, quiet conversations, closing doors) — noise cannot be eliminated entirely, but unnecessary noise can; offer earplugs and eye masks; comfortable room temperature.
3. Cluster care to allow blocks of uninterrupted sleep (ideally 90 minutes or more); schedule medications and vital signs to avoid waking the client when safe.
4. Relieve symptoms that disturb sleep: give analgesics before bedtime for clients with chronic pain; manage dyspnea, nausea, and nocturia (fluids earlier in the day, diuretics in the morning); toilet before sleep.
5. Support bedtime routines: personal hygiene, reading, relaxation, prayer, back rub, warm drink without caffeine.
6. CPAP use in hospital: clients with OSA should use their own CPAP at night and during naps, especially when receiving opioids; monitor SpO₂.
7. Nonpharmacologic first: relaxation, positioning, and environment before requesting a hypnotic.
8. Document sleep patterns and the client's own report of rest.

Sleep hygiene and behavioral strategies

• Keep the same wake time every day, including weekends.
• Go to bed only when sleepy; if unable to sleep after about 20 minutes, get up and do something quiet in dim light, then return (stimulus control).
• Use the bed only for sleep and sex; keep the bedroom dark, quiet, and cool.
• Avoid caffeine in the afternoon and evening, alcohol near bedtime (it fragments sleep), nicotine, and heavy meals late at night.
• Regular exercise, but not within a few hours of bedtime.
• Limit screens before bed; avoid long or late naps.
• A warm bath about 1–2 hours before bed can help sleep onset.

Hypnotic safety: never combine with alcohol or opioids; do not drive the next morning if drowsy; rise slowly to prevent falls; do not stop long-term benzodiazepines abruptly.

Shift workers: caffeine early in the shift rather than toward the end; bright light during the night shift; dark, quiet bedroom (blackout curtains) and a consistent sleep block after work; plan rest before driving home.

OSA: use CPAP every night; clean the mask and tubing; weight loss; avoid alcohol and sedatives; sleep on the side.

• N3 (deep) sleep = growth hormone and tissue repair; REM = dreaming and memory, muscle atonia
• Sleep cycles last about 90 minutes; adults need at least 7 hours
• Aging: less deep and REM sleep, more awakenings, early morning waking (advanced phase)
• Sleep history and diary come first in assessment
• Epworth = daytime sleepiness; PSQI = sleep quality; actigraphy = long-term patterns at home
• Polysomnography records EEG, EOG, EMG, airflow, SpO₂ — gold standard; avoid caffeine and alcohol before
• OSA: loud snoring, witnessed apneas, daytime sleepiness; CPAP
• Restless legs: urge to move, relieved by movement; check iron
• REM sleep behavior disorder: acting out dreams
• CBT-I is first-line for chronic insomnia
• Hypnotics + alcohol → additive CNS and respiratory depression; avoid benzodiazepines, Z-drugs, and diphenhydramine in older adults
• Hospital: dim at night, bright by day, reduce noise, cluster care, analgesia at bedtime