awakening occurs most commonly during or after a period of REM sleep, as body temperature is rising.

Continuation during wakefulness

Ernest Hartmann discovered in 1968 that humans seem to continue a roughly 90-minute ultradian rhythm throughout a 24-hour day, whether they are asleep or awake. According to this hypothesis, during the period of this cycle corresponding with REM, people tend to daydream more and

1.Previous
3.Next