Deep sleep.
Sleep behaves differently at night and is divided into four phases: light sleep, which lasts about 10% of the time, the average sleep, which lasts approximately 45% of the time, deep sleep and REM sleep.
Deep sleep covers about 25% of the night. At this stage, brain activity slows, releasing low-signal waves. It is a much more difficult phase to wake up. If it does, you may be disoriented for a few minutes. At this stage episodes of night terrors and sleepwalking may occur.
Note: The phase of REM sleep is the phase in which memory and learning consolidation occurs.
