B

Module 1.5b Sleep: Sleep Stages and Theories

Learning Targets

  • Explain sleep as a state of consciousness.

  • Describe how biological rhythms impact daily functioning.

  • Outline the biological rhythm of sleeping and dreaming stages.

  • Discuss the interaction between biology and environment in sleep patterns.

  • Summarize sleep's functions.

Overview of Sleep

  • Sleep is a periodic and natural loss of consciousness, distinct from coma or anesthesia.

  • Sleep involves brain activity and information processing outside conscious awareness.

Biological Rhythms

  • Circadian rhythms are 24-hour biological cycles affecting temperature, wakefulness, and sleep.

  • Body temperature rises in the morning, peaks during the day, and dips in the afternoon.

  • Age-related shifts from 'owls' (evening energy) to 'larks' (morning preferences) are common.

Sleep Stages

  • Sleep consists of cycles lasting approximately 90 minutes, including NREM (Stages 1-3) and REM.

  • NREM stages include:

    • Stage 1: Transition to sleep (alpha to theta waves).

    • Stage 2: Relaxed sleep with sleep spindles.

    • Stage 3: Deep sleep with delta waves.

  • REM (Rapid Eye Movement) is associated with vivid dreams and paradoxical sleep.

Functions of Sleep

  • Sleep protects by conserving energy and limiting risk during vulnerable periods.

  • Restores the body, allowing repair and immune system functioning.

  • Aids memory consolidation, moving memories into long-term storage.

  • Supports creative thinking and problem-solving.

  • Facilitates growth by releasing growth hormones during slow-wave sleep.

  • Conserves energy, ensuring efficiency in wakeful periods.

Environmental Influences on Sleep

  • Factors such as culture, social norms, and genetics influence sleep duration and quality.

  • Modern lighting and lifestyle can disrupt natural sleep patterns; artificial light affects melatonin production.

  • Not everyone requires a fixed amount of sleep; individual needs vary widely with age and lifestyle.

Summary of Sections

  • Sleep is critical for physical health, cognitive processes, and emotional well-being.

  • Understanding biological rhythms, sleep stages, and functions can enhance sleep quality.