There are more than 100 different types of sleeping disorder and waking disorders have been identified. They can be grouped within 4 main categories: problems with staying and falling asleep, problems with staying awake, problems with adhering to a regular sleep schedule, and sleep

Narcolepsy is a chronic (long-lasting) neurological (affecting the brain or nerves) disorder that involves your body's central nervous system. The central nervous system is the "highway" of nerves that carries messages from your brain to other parts of your body. For people with narcolepsy, the messages about when to sleep and when to be awake sometimes hit roadblocks or detours and arrive in the wrong place at the wrong time. This is why someone who has narcolepsy, not managed by medications, may fall asleep while eating dinner or engaged in social activities - or at times when he or she wants to be awake.

When we switch into REM sleep, our breathing becomes more rapid, irregular, and shallow, our eyes jerk rapidly in various directions, and our limb muscles become temporarily paralyzed. Our heart rate increases, our blood pressure rises, and males develop penile erections. When people awaken during REM sleep, they often describe bizarre and illogical tales - dreams.

During stage 1, which is light sleep, we drift in and out of sleep and can be awakened easily. Our eyes move very slowly and muscle activity slows. People awakened from stage 1 sleep often remember fragmented visual images. Many also experience sudden muscle contractions called hypnic myoclonia, often preceded by a sensation of starting to fall. These sudden movements are similar to the "jump" we make when startled. When we enter stage 2 sleep, our eye movements stop and our brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles. In stage 3, extremely slow brain waves called delta waves begin to appear, interspersed with smaller, faster waves. By stage 4, the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep

Some topics in this essay:
, NREM REM, rem sleep, sleep disorder, brain waves, people narcolepsy, falling asleep, narcolepsy symptoms, stage 1, eye movement, deep sleep, sleep paralysis, sleep disorder polysomnogram, person falling asleep, paralysis vivid dreams, lack muscle tone, stage 2 sleep,