Rest and Sleep: Physiology, Disorders, and Health Implications

Rest, Sleep, and Wakefulness

Definitions and Concepts

Rest and sleep are essential components of human health, contributing to physical and mental restoration. The sleep–wake cycle regulates periods of activity and inactivity.

• Rest: A decreased state of activity, leading to feelings of refreshment.

• Sleep: A state of rest with altered consciousness and relative inactivity; vital for restoration of mental and physical function.

• Wakefulness: Periods of mental activity and energy expenditure.

Physiology of Sleep

Neural Regulation

Sleep is regulated by several brain regions and systems:

• Reticular Activating System (RAS): Facilitates reflex and voluntary movements; controls alertness.

• Bulbar Synchronizing Region: Works with the RAS to regulate sleep.

• Hypothalamus: Acts as the control center for sleeping and waking.

Stages of Sleep

NREM and REM Sleep

Sleep is divided into two main types: Non-rapid eye movement (NREM) and Rapid eye movement (REM).

• NREM Sleep: Four stages, ranging from light to deep sleep.

• Stages I & II: Light sleep, 5%–50% of total sleep; easy to arouse (Stage II is the answer to Question #1).

• Stages III & IV: Deep sleep (delta sleep), 10% of total sleep; difficult to arouse.

• REM Sleep: 20%–25% of nightly sleep; increased pulse, respiratory rate, blood pressure, metabolic rate, and body temperature; decreased skeletal muscle tone and deep tendon reflexes.

Sleep Cycle

Normal Progression

A typical sleep cycle involves progression through NREM stages, reversal, and entry into REM sleep.

• Progression: I → II → III → IV

• Reversal: IV → III → II → REM

• Cycle repeats throughout the night.

Effects of Insufficient Sleep

Health Implications

Insufficient sleep can negatively impact health and development.

• May affect normal growth and development in children.

• May increase obesity risk in children and adults.

• Lowers leptin (satiety hormone) and elevates ghrelin (hunger hormone).

Developmental Patterns of Sleep

Age-Related Differences

Sleep needs and patterns vary by age group:

• Newborns and infants

• Toddlers

• Preschoolers

• School-aged children

• Teenagers

• Young adults

• Middle-aged adults

• Older adults

Factors Affecting Rest and Sleep

Influencing Variables

Multiple factors can influence sleep quality and quantity:

• Developmental considerations

• Motivation

• Culture

• Lifestyle and habits

• Environmental factors

• Psychological stress

• Illness

• Medications

Lifestyle and Habits

• Activity and exercise promote relaxation and increase both REM and NREM sleep.

• Dietary habits: L-tryptophan (amino acid) promotes sleep; small protein and complex carbohydrate snacks before bed improve sleep.

• Alcohol limits REM and delta sleep.

• Caffeine blocks adenosine, preventing drowsiness.

• Smoking and nicotine are associated with poorer sleep.

Psychological Stress

Impact on Sleep

Stress from illness or life situations can disturb sleep, reduce REM sleep, and increase anxiety.

Illnesses Associated With Sleep Disturbances

Medical Conditions

• Gastroesophageal reflux

• Coronary artery diseases

• Epilepsy seizures

• Liver failure and encephalitis

• Hypothyroidism

• End-stage renal disease

Medications that Affect Sleep

Drug Effects

• Benzodiazepines

• Amphetamines

• Antidepressants

• Diuretics

• Antiparkinsonian drugs

• Antihypertensives

• Steroids

• Decongestants

• Caffeine

• Asthma medications

Note: Barbiturates, amphetamines, and antidepressants decrease REM sleep (see Question #2).

ICSD Classification of Sleep Disorders

Types of Sleep Disorders

• Insomnia

• Sleep-related breathing disorders

• Central disorders of hypersomnolence

• Circadian rhythm sleep–wake disorders

• Parasomnias

• Sleep-related movement disorders

• Other sleep disorders

Insomnia

Definition and Prevalence

Insomnia is characterized by difficulty falling asleep, intermittent sleep, or difficulty maintaining sleep despite adequate opportunity.

• 30%–35% of adults in the U.S. report insomnia.

• Often associated with depression and circadian rhythm disruptions.

• May be short-term or chronic.

Central Disorders of Hypersomnolence

Idiopathic Hypersomnia and Narcolepsy

• Idiopathic hypersomnia: Excessive sleep, especially during the day.

• Narcolepsy: Excessive daytime sleepiness and sudden sleep attacks; up to 70% experience cataplexy (sudden loss of muscle tone).

Sleep-Related Breathing Disorders

Obstructive Sleep Apnea (OSA)

OSA is characterized by five or more obstructive respiratory events per hour during sleep.

• Apnea: Absence of breathing.

• Hypopnea: Diminished breathing efforts.

• Symptoms: Sleepiness, fatigue, insomnia, snoring, nocturnal respiratory disturbance, observed apnea, gasping for air.

Circadian Rhythm Sleep–Wake Disorders

Characteristics

• Chronic or recurrent disruption of sleep–wake rhythm.

• Caused by alteration or misalignment of internal circadian timing system.

• Associated distress or impairment lasting at least 3 months (except jet lag).

Parasomnias

Types and Features

• Somnambulism: Sleepwalking (see Question #5).

• REM sleep behavior disorder (RBD)

• Sleep terrors

• Nightmare disorder

• Sleep enuresis (bedwetting)

• Sleep-related eating disorder

Sleep-Related Movement Disorders

Restless Legs Syndrome (RLS)

RLS, also known as Willis–Ekbom disease, affects up to 15% of the population, especially middle-aged and older adults.

• Symptoms: Unpleasant creeping, crawling, or tingling sensations in the legs; inability to lie still.

• Nonpharmacologic treatments are available.

Assessment of Sleep Disturbances

Obtaining a Sleep History

• Nature and cause of problem

• Related signs and symptoms

• Onset and frequency

• Impact on daily living

• Severity and treatment options

• Coping strategies and treatment success

Screening Tools

• Sleep Diary

• Epworth Sleepiness Scale

• Pittsburgh Sleep Quality Index (PSQI)

• STOP-Bang Questionnaire (OSA)

• Stanford Sleepiness Scale

Sleep Diary Information

• Time of retiring and attempting to sleep

• Approximate time of falling asleep

• Awakenings and resumption of sleep

• Morning awakening time

• Stressors, food, drink, medications, activities, worries, and anxieties affecting sleep

Sleep Characteristics to Assess

• Restlessness

• Sleep postures

• Sleep activities

• Snoring

• Leg jerking

Physical Assessment Findings

• Energy level

• Facial characteristics

• Behavioral characteristics

• Physical data suggestive of sleep problems

Interventions to Promote Sleep

Nursing and Lifestyle Strategies

• Prepare a restful environment

• Promote bedtime rituals

• Offer appropriate bedtime snacks and beverages (e.g., toast, see Question #3)

• Promote relaxation and comfort

• Respect normal sleep–wake patterns

• Schedule care to avoid disturbances

• Use medications as needed

• Teach about rest and sleep

Treatment for Dyssomnias

Pharmacologic and Nonpharmacologic Therapies

• Pharmacologic: Sedatives, hypnotics

• Nonpharmacologic: Cognitive behavioral therapy (CBT), progressive muscle relaxation, stimulus control, sleep restriction, sleep hygiene, biofeedback, relaxation therapy

Summary Table: Sleep Disorders Classification

Disorder Type	Main Features	Examples
Insomnia	Difficulty falling or staying asleep	Short-term, chronic insomnia
Sleep-related breathing disorders	Abnormal breathing during sleep	Obstructive Sleep Apnea (OSA)
Central disorders of hypersomnolence	Excessive daytime sleepiness	Narcolepsy, idiopathic hypersomnia
Circadian rhythm sleep–wake disorders	Disruption of sleep–wake timing	Shift work disorder, jet lag
Parasomnias	Abnormal behaviors during sleep	Somnambulism, sleep terrors, nightmares
Sleep-related movement disorders	Abnormal movements during sleep	Restless Legs Syndrome (RLS)

Key Terms and Definitions

• Leptin: Hormone signaling satiety; low levels increase hunger.

• Ghrelin: Hormone promoting hunger; high levels increase appetite.

• Cataplexy: Sudden loss of muscle tone, often seen in narcolepsy.

• Somnambulism: Sleepwalking, a type of parasomnia.

• Restless Legs Syndrome (RLS): Urge to move legs, often with unpleasant sensations.

Additional info: Sleep hygiene measures include maintaining a regular sleep schedule, avoiding stimulants before bedtime, and creating a comfortable sleep environment. Cognitive behavioral therapy (CBT) is effective for chronic insomnia. Sleep restriction involves limiting time in bed to actual sleep time to improve sleep efficiency.