sleep stages animation. Text: The Stages Of Sleep - You cycle through three stages of non-REM and REM (rapid eye movement) sleep numerous times a night. Stage 1 - Light sleep within minutes of nodding off, where you're somewhat alert and can be woken up easily. Stage 2 - Light sleep, where brain waves and heart rate slow down as the body temperature drops. This is your body getting ready for a deep sleep. Stage 3 - The beginning of deep sleep, where your body repairs muscles and tissues, stimulates growth and development, boosts immune function, and builds up energy for the next day. REM - First occurs in about 70 to 90 minutes after you fall asleep, and each REM cycle can last up to an hour. This is when most dreaming occurs.
