stages of sleep - ultradian rhythm

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

  Distinctive brainwave patterns
• How often do brainwave patterns repeat during sleep?

  Every 90 minutes
• What is the 24-hour circadian rhythm known as?

  The sleep/wake cycle
• What is the difference between circadian, infradian, and ultradian rhythms?

  Circadian rhythms repeat once a day, infradian rhythms are less frequent than daily, and ultradian rhythms are more frequent than daily
• What are the five main distinctive brainwave patterns?

  Delta, theta, alpha, beta, and gamma
• How does sleep progress through the stages?

  From N1 to N3, moving from light sleep to deeper sleep
• What is the first stage of sleep known as?

  N1
• What characterizes N1 sleep?

  Easy to wake, sensation of falling, and hypnic jerks
• What type of waves are present in N1 sleep?

  Theta waves
• What happens during N2 sleep?

  Body relaxes, heart rate and body temperature fall, and sleep spindles occur
• What is the EEG pattern in N2 sleep characterized by?

  Slowing brainwaves, sleep spindles, and K-complexes
• What defines N3 sleep?

  Deep sleep with slow frequency and high amplitude delta waves
• What is REM sleep also known as?

  Paradoxical sleep
• What occurs during REM sleep?

  Vivid dreaming and rapid eye movement
• How does the proportion of REM sleep change throughout the night?

  Each cycle tends to include a larger proportion of REM sleep
• How many full sleep cycles do humans usually have in one night?

  4 to 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 find about ultra marathon runners?

  They had longer sleep and increased slow-wave sleep
• What is one debated function of REM sleep?

  Memory consolidation
• What is nocturnal penile tumescence (NPT)?

  Development of an erection during the night
• How does NPT relate to REM sleep?

  NPT occurs in sync with REM sleep patterns
• What are the stages of sleep and their characteristics?

  • N1: Light sleep, easy to wake, theta waves, hypnic jerks
  • N2: Deeper sleep, sleep spindles, K-complexes, heart rate and temperature fall
  • N3: Deep sleep, delta waves, fully relaxed
  • REM: Active brain state, vivid dreams, rapid eye movement, body paralysis
• What are the connections between circadian and ultradian rhythms?

  • Circadian rhythms: 24-hour cycle (sleep/wake)
  • Ultradian rhythms: More frequent than daily (e.g., sleep cycles)
  • Both may use the same internal body clock (endogenous pacemaker)
• What are the implications of understanding sleep stages for technology?

  • Development of devices to track sleep
  • Helps individuals improve sleep quality
  • Avoiding grogginess from waking in stage 4
• What adaptations occur in sleep stages as individuals develop?

  • Babies have about 80% of sleep in REM
  • Adults have 20-25% in REM
  • Stages adapt to developmental needs