Eyes close, breathing becomes slow and regular, pulse rate slows, and body temperature drops. Loss of consciousness, enter light sleep, heart rate slows. Breathing becomes more irregular, body muscles relax. Small irregular brain waves with some alpha. If awakened, may or may not say they were asleep.
Delta waves begin to appear.
Pure delta waves. Reached about 1 hour after sleep begins. State of oblivion. The shifts back and forth appear throughout the night. Rapid eye movements.