Light sleep, or stage one, is the period of time when you are not fully awake but have not quite nodded off yet either. Have you ever had one of those dreams where you fall off a cliff and it wakes you up? Those usually occur during stage one sleep. Other hallucinations can also occur during this stage, such as feeling something touching you or hearing a knock.
Once you have transitioned from stage one to stage two, you are fully asleep. Stage two involves no eye movement and slower brain waves. Stage three is when deep sleep begins to occur, slowing down brain waves even more. Delta waves, or extremely slow brain waves, are the only kind of waves that occur in stage four. During this stage, the body is in a deep state of relaxation, making it very hard for a person to wake from. Stage four is when some children experience bed wetting, sleep walking and night terrors.
Perhaps the most talked about stage of sleep is REM. REM sleep follows stage four, turning the slow delta waves into waves that are at the same level as when a person is awake. Breathing becomes rapid and shallow, and there is rapid eye movement, hence the name REM. If awakened during REM, you will be able to remember your dreams, because most dreaming occurs during this stage. For this reason, limbs become temporarily paralyzed during REM, preventing a person from acting out his or her dreams. Once the REM stage is over, a person will slip right back into stage one sleep and repeat the cycle all over again.
So now that you know all about sleep, why is all this such a big deal? There are many reasons sleep is so necessary, both short term and long term. Some short term affects of sleep deprivation, according to WebMD, include decreased alertness, cognitive impairment, stress on relationships and poor quality of life. More seriously, long term affects include high blood pressure, heart attack or failure, stroke, obesity, depression, ADD and fetal growth retardation.
Knowing the risks involved, maybe next time you're tempted to stay awake and ponder the meaning of life, you'll think twice, sleep tight, and don't let the bed bugs bite.