Sleep Cycles and Disorders
Ever feel that sudden jerk while dozing off in class? That's a hypnic jerk in Stage 1 sleep, the lightest sleep phase where you might not even realize you were sleeping. As you drift deeper into Stage 2, your heart rate slows, and brief bursts of brain activity called sleep spindles occur.
The deepest phase, Stage 3, is when you'd wake up feeling disoriented and growth hormones are released. REM sleep is where dreams happen—your brain activity actually resembles your waking state! This completes the full sleep cycle that repeats throughout the night.
Sleep disorders can significantly impact health. Nightmares occur during REM sleep, while night terrors happen in deep sleep, causing extreme fear without fully waking. People with sleep apnea stop breathing for 10+ seconds, and those with narcolepsy fall directly into REM sleep during daytime. Insomnia—the inability to fall or stay asleep—affects millions of people.
Did you know? In REM behavior disorder (RBD), people physically act out their dreams because the mechanism that normally paralyzes muscles during REM sleep fails!
Hypnosis works through either dissociation (part of your consciousness remains aware while another doesn't) or social cognitive theory (you're essentially playing a role). Think about times you've driven somewhere but can't remember passing certain landmarks—that's dissociation at work!
