● Stage 1 straddles the fine line between awake and asleep.
● Stage 2 is when body temperature cools and you become oblivious to your surroundings.
● Stages 3 & 4 are the deeper levels of sleep—breathing slows, blood pressure drops and muscles relax.
● REM sleep, short for “rapid eye movement” sleep, happens about every 90 minutes and it’s during REM that the
most vivid dreams occur. You typically go from REM back into stage two and start the cycle over,
repeating the stages until morning, when the body releases cortisol to help you return to alertness