Chapter 35: Rest and Sleep

NREM Sleep

Non-rapid eye movement sleep, comprising 75-80% of total sleep with distinct stages.

Stage I of NREM Sleep

Light sleep, a transition phase lasting 5-10 minutes, where muscle activity slows and hypnic jerks may occur.

Stage II of NREM Sleep

Represents about 50% of sleep, characterized by further slowing of body systems and sleep spindles aiding memory consolidation.

Stage III & IV of NREM Sleep

Also called deep sleep or slow-wave sleep, crucial for tissue repair, muscle growth, and immune function.

REM Sleep

Rapid eye movement sleep, accounting for 20-25% of sleep where vivid dreams occur, vital for emotional regulation and memory processing.

Reticular Activating System (RAS)

Part of the brainstem that regulates wakefulness and sleep onset.

Circadian Rhythms

The biological clock regulated by the hypothalamus, influencing sleep-wake cycles, appetite, and hormone release.

Sleep Apnea

Temporary cessation of breathing during sleep, often leading to fragmented sleep and excessive daytime drowsiness.

Chronic Insomnia

Persistent difficulty in falling or staying asleep, often resulting from stress or anxiety, leading to fatigue and cognitive impairment.

Restless Legs Syndrome (RLS)

A condition characterized by tingling or crawling sensations in the legs, often disrupting sleep.

Polysomnography

A diagnostic test that measures brain activity, oxygen levels, and body movements during sleep.

Sleep Hygiene

Practices that promote healthy sleep, including consistent bedtimes and creating a calming pre-sleep routine.

Cataplexy

A sudden loss of muscle control, often triggered by strong emotions, commonly associated with narcolepsy.

Environmental Factors Affecting Sleep

Includes noise, light, and temperature extremes that can disrupt sleep quality.

Importance of Sleep for Cognitive Function

Sleep enhances memory consolidation and supports creativity and problem-solving.