The Five Cycle of Sleep
Your brain and muscle activity will slow down. Drowsiness sets in.
Your body will enter into a light sleep and the eye movements stop and your breathing slows. Body temperature is also drops.
Your body will enter into a deep sleep and the brain waves are extremely slow and the pressure falls.
This is the stage that deepest sleep are occurs. Rhythmic breathing and limited muscle activity are there. Some person are difficult to awaken at this stage.
This is the stage of Rapid Eye Movement (REM). During this stage muscles relax, heart rate will rise. There are also intense brain activities and some dreaming occurs.