Stages of the different stages of sleep rest are identifiable by tracking changes in brain waves during rest (beta waves, waves alpha and theta waves). Those who sleep generally pass through five stages: 1, 2, 3, 4, and REM sleep. A full sleep cycle takes an average of 90 to 110 minutes and five stages are repeated up to five times during the night. The first REM stages tend to be shorter and periods of deep sleep longer, but later in the night, REM periods become longer and the deep sleep time is shortened. 1St stage of sleep can last only a few minutes, the dream is lightweight and can wake up easily. Brainwaves are mostly of high amplitude, slow waves and occasional alpha waves (such as those that exist when one is awake), it is the transition from wakefulness to sleep, the eyes move slowly and muscle activity is slowing.

During this time many people experience preceded by sudden muscle contractions of a feeling of being falling from their mattresses. This stage of sleep occupies 5 percent of total sleep time for young adults. 2Nd stage of sleep decreases both the breathing and heart rate, sleep is deeper to that in the first stage, stops the movement of eyes and brain waves are slow with only some occasional bursts of rapid brain waves. The percentage of the total time of sleep which occupies this stage is a 44 to 55 percent in young adults. 3 rd and 4 th stage of sleep these are deeper sleep stages, here the brain waves are slower. In the third stage extremely slow brain waves (delta waves) are interspersed with waves smaller, faster, while in the fourth stage, the brain produces waves delta almost exclusively. Phases 3 and 4 are referred to as deep sleep, and it is very difficult to awaken someone of them.