35. rest/sleep

Circadian rhythms

Definition: Predictable fluctuations in processes that occur in repeated cycles of time, completing a full cycle every 24 hours.

Clinical Example: A nurse working the night shift experiencing a disruption in their natural sleep wake cycle, which causes them to sleep from 2 PM to 8 PM instead of resting when their biological clock dictates.

Enuresis

Definition: Urinating during sleep or bedwetting.

Clinical Example: A child older than 5 years who has never regularly stayed dry during sleep, or an adult who previously stayed dry but begins bedwetting at least twice a week due to underlying issues like a urinary tract problem or sleep apnea.

Hypersomnia

Definition: Constant or recurrent episodes of extreme sleepiness (hypersomnolence), particularly during the day, where a person may sleep for 10 or more hours at night and take daytime naps but still feel sleepy.

Clinical Example: An adolescent or young adult falling asleep while driving due to severe daytime drowsiness, or waking up disoriented and irritable with slower speech and thinking processes.

Insomnia

Definition: A sleep disorder characterized by difficulty falling asleep, intermittent sleep, or difficulty maintaining sleep, despite adequate opportunity and circumstances to sleep.

Clinical Example: A patient lying awake in bed for 3 or 4 hours before falling asleep, or waking up frequently during the night due to stress and worrying about their children.

Melatonin

Definition: A natural chemical or hormone produced at night that decreases wakefulness, promotes sleep, and is thought to regulate the sleep wake cycle and circadian rhythms.

Clinical Example: A patient taking an over the counter melatonin supplement to ease the transition to a new schedule or time zone caused by jet lag, or to help initiate sleep.

Narcolepsy

Definition: A chronic neurologic disorder characterized by excessive daytime sleepiness and frequent overwhelming urges to sleep or inadvertent daytime lapses into sleep.

Clinical Example: A person literally falling asleep standing up, while driving a car, in the middle of a conversation, or while swimming.

Non rapid eye movement (NREM) sleep

Definition: A state comprising about 75% to 80% of total sleep time that consists of four stages, progressing from light sleep (stages I and II) to deep, delta sleep (stages III and IV) where the parasympathetic nervous system dominates.

Clinical Example: A sleeping patient experiencing a decrease in pulse, respiratory rate, blood pressure, metabolic rate, and body temperature, making it increasingly difficult to arouse them.

Obstructive sleep apnea (OSA)

Definition: A potentially serious sleep disorder in which the throat muscles intermittently relax and block the airway during sleep, causing breathing to repeatedly stop and start.

Clinical Example: An adult whose breathing ceases for 10 to 20 seconds during sleep, causing blood oxygen levels to drop, leading them to startle, snort, or awaken gasping for air.

Parasomnias

Definition: Episodes or behaviors that occur during arousals from REM sleep or partial arousals from NREM sleep that disturb the patient or others.

Clinical Example: A child waking up screaming in intense fear (sleep terrors), or a patient acting out violent dreams by thrashing around in bed (REM sleep behavior disorder).

Rapid eye movement (REM) sleep

Definition: A stage of sleep consuming 20% to 25% of a person's nightly sleep time, characterized by dreaming, increased metabolic rate and vital signs, and depressed skeletal muscle tone.

Clinical Example: A sleeping patient whose eyes dart back and forth quickly, with irregular respirations and small muscle twitching on the face, who vividly recalls a dream if awakened.

Rest

Definition: A condition in which the body is in a decreased state of activity, with the consequent feeling of being refreshed.

Clinical Example: A patient taking time for quiet, enjoyable activities such as listening to music, reading, or receiving a backrub to promote physical and mental relaxation.

Restless legs syndrome (RLS)

Definition: A common sleep related neurologic disorder involving involuntary movement of the legs when the body is at rest, characterized by unpleasant creeping, crawling, or tingling sensations.

Clinical Example: An older adult who cannot lie still at night and feels an irresistible urge to get out of bed and pace or move their legs to relieve cramping or crawling sensations.

Sleep

Definition: A state of rest accompanied by altered consciousness and relative inactivity that is part of the sleep wake cycle and provides restoration of mental and physical function.

Clinical Example: A healthy young adult obtaining 7 to 9 hours of uninterrupted slumber at night, allowing their body to progress through necessary REM and NREM stages to maintain physical and psychological well being.

Sleep cycle

Definition: A repeating pattern of sleep stages where a person passes consecutively through the four stages of NREM sleep, reverses from stage IV to stage II, and then enters REM sleep before starting the cycle over.

Clinical Example: A young adult going through four or five 90 to 110 minute cycles per night, experiencing more deep delta sleep in the first half of the night and longer periods of REM sleep as morning approaches.

Sleep deprivation

Definition: The cumulative effect of a person not having sufficient sleep, representing a decrease in the amount, consistency, or quality of sleep.

Clinical Example: An intensive care unit patient exhibiting daytime fatigue, acute confusion, irritability, and impaired mental abilities due to frequent awakenings for treatments and environmental noise.

Sleep hygiene

Definition: A set of behaviors or habits that may influence sleep quality, involving the use of behaviors to facilitate sleep and the avoidance of behaviors that interfere with sleep.

Clinical Example: A patient restricting their intake of caffeine and alcohol in the evening, eating a light carbohydrate and protein snack, and sleeping in a cool, dark, and quiet room.

Somnambulism

Definition: A parasomnia (also known as sleepwalking) where automatic behaviors occur during sleep, ranging from sitting up in bed to walking around the house or outside.

Clinical Example: A sleeping patient getting out of bed and performing a familiar behavior like dressing or washing, completely unaware of their environment and unresponsive to others.