The Stages Of Sleep

• What can be observed by an electroencephalogram while you sleep?

  Distinctive brainwave patterns
• What is the 24-hour circadian rhythm known as?

  The sleep/wake cycle
• How often do brainwave patterns repeat during sleep?

  Every 90 minutes
• What is the 28-day rhythm known as?

  The menstrual cycle
• What is the ultradian rhythm?

  A rhythm that is more frequent than every day
• What are the three types of rhythms discussed?

  • Circadian rhythm: 24-hour cycle (sleep/wake)
  • Infradian rhythm: Less frequent than daily (menstrual cycle)
  • Ultradian rhythm: More frequent than daily (stages of sleep)
• What do the frequency and amplitude of brainwaves represent?

  Frequency is the number of waves per second, amplitude is the size of the wave
• What are the five main distinctive brainwave patterns?

  • Delta
  • Theta
  • Alpha
  • Beta
  • Gamma
• How does sleep progress through the stages?

  From light sleep to deeper sleep
• What are the four distinct stages of sleep?

  N1, N2, N3, and REM sleep
• What characterizes N1 sleep?

  A sensation of moving from awake to asleep with easy wakefulness
• What are hypnic jerks?

  Sudden movements that occur as one transitions from awake to asleep
• What are hypnagogic hallucinations?

  Mild auditory or visual hallucinations during N1 sleep
• How can N2 sleep be identified on an EEG?

  By slowing brainwaves and occasional bursts called sleep spindles and K complexes
• What is N3 sleep also known as?

  Slow wave sleep
• What characterizes REM sleep?

  Active brain state similar to wakefulness with rapid eye movement
• What happens to the body during REM sleep?

  The body is paralyzed
• What is the relationship between REM sleep and dreaming?

  REM sleep is associated with vivid dreaming
• How many full sleep cycles do humans usually have in one night?

  Between 4 and 5 cycles
• What did Kleitman's studies in 1957 demonstrate?

  Regular sleep cycles over the course of a night
• What did Shapiro's research in 1981 show about sleep?

  Intense physical activity resulted in longer sleep and increased slow-wave sleep
• What is the debated function of REM sleep?

  Memory consolidation
• What did Hyder's research in 1970 suggest about REM sleep?

  It is for brain recovery
• What percentage of their sleep do babies spend in REM sleep?

  About 80%
• How does understanding sleep stages benefit individuals?

  It can help track and improve sleep quality
• What are the implications of understanding the sleep cycle?

  • Helps avoid grogginess and disorientation
  • Leads to a happier, healthier, and more productive population
  • Informs the development of sleep tracking technology
• What change occurred in 2007 regarding sleep stages?

  The old stages of sleep were combined into a new NREM stage
• How are circadian and ultradian rhythms connected?

  They may use the same internal body clock
• What is nocturnal penile tumescence (NPT)?

  Development of an erection during the night
• How often does nocturnal penile tumescence occur during REM sleep?

  About five times a night
• What is the suggested purpose of nocturnal penile tumescence?

  To provide a fresh supply of oxygenated blood to the penis
• What are the key findings from the studies on sleep cycles and REM sleep?

  • Regular sleep cycles observed in adults
  • REM sleep associated with vivid dreaming
  • Physical activity influences sleep duration and quality