PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.

Detailed explanation-2: -Stage 4 is an even deeper sleep where the brain waves further slow and sleepers are very difficult to wake. It’s believed that tissue repair occurs during the stage of sleep and that hormones are also released to help with growth.

Detailed explanation-3: -Stage 3 sleep is also known as N3 or deep sleep, and it is harder to wake someone up if they are in this phase. Muscle tone, pulse, and breathing rate decrease in N3 sleep as the body relaxes even further. The brain activity during this period has an identifiable pattern of what are known as delta waves.

Detailed explanation-4: -The last NREM stage is stage 4, which lasts approximately 20 to 40 minutes in the first cycle and makes up about 10 to 15 percent of sleep. The arousal threshold is highest for all NREM stages in stage 4.

Detailed explanation-5: -As your body progresses through the four sleep cycle stages-stages 1 through 3 (non-rapid eye movement, or NREM) and stage 4 (rapid eye movement, or REM), it transitions through different biological processes that affect your temperature, breathing, cells, and muscles.