Sleep Fundamentals: Hygiene, Disorders, Cycles, and Circadian Rhythms

Sleep Hygiene

• Practices that promote better sleep quality:
  • Establish a consistent sleep schedule
  • Create a sleep-conducive environment (dark, quiet, cool)
  • Avoid stimulating activities before bedtime
  • Avoid caffeine, nicotine, and electronics before bedtime
  • Get regular exercise, but not before bedtime
  • Avoid heavy meals close to bedtime
  • Limit naps to 20-30 minutes and avoid napping close to bedtime
  • Manage stress through relaxation techniques (meditation, deep breathing)

Sleep Disorders

• Common sleep disorders:
  1. Insomnia: chronic difficulty falling or staying asleep
  2. Sleep Apnea: interrupted breathing during sleep
  3. Narcolepsy: excessive daytime sleepiness and sudden sleep attacks
  4. Restless Leg Syndrome: uncomfortable sensations in the legs during sleep
  5. Sleepwalking: performing tasks while asleep
• Sleep disorders can be caused by:
  • Genetics
  • Lifestyle factors (e.g., substance abuse, irregular sleep schedule)
  • Medical conditions (e.g., sleep apnea, restless leg syndrome)
  • Medications
  • Aging

Sleep Cycles

• A full sleep cycle lasts around 90-120 minutes
• Each cycle consists of:
  1. N1 (NREM 1): Transition from wakefulness to sleep, characterized by slow eye movements
  2. N2 (NREM 2): Light sleep, body temperature cools, heart rate slows
  3. N3 (NREM 3): Deep sleep, slow delta brain waves, difficult to wake
  4. REM (Rapid Eye Movement): Brain active, dreams occur, muscles paralyzed
• Most people experience 4-6 sleep cycles per night

Circadian Rhythms

• Internal biological processes that regulate our sleep-wake cycle
• Controlled by the suprachiasmatic nucleus (SCN) in the brain
• Influenced by:
  • Light exposure
  • Melatonin production
  • Body temperature
  • Hormone secretion
• Circadian rhythms can be affected by:
  • Jet lag
  • Shift work
  • Irregular sleep schedules
  • Aging