Sleep has two fundamental stages. There is non-REM sleep and paradoxical sleep: non-REM means non-rapid eye movements. NREM sleep has four stages. Each step can last from five minutes to fifteen minutes. The first stage consists of alpha waves. Alpha waves correspond to normal electrical activity when the brain is unconscious or relaxed. During the first stage, a person may be woken up easily, and if they wake up, they will feel like they haven't slept. Also at this stage you often feel a sensation of falling and suddenly wake up, this is due to sudden muscle contraction. This muscle contraction is called a “hypnagogic jerk”. It is one of two forms of sleep paralysis. During the second stage, your muscles continually relax and then tense. Your heart rate slows down and body temperature also decreases. This stage prepares you for the deep sleep stage. Stages three and four are almost exactly the same thing, except that in stage four there are more delta waves. (Delta waves are waves of deep sleep, which show electrical activity in the brain.) These two stages are both stages of deep sleep, and if you are awake during these stages, you might feel disoriented. Once the cycle completes it goes to REM, once REM completes it goes back. In non-REM sleep, the body regenerates and the immune system develops and strengthens. (Kimball Johnson, 2014)REM stands for “Rapid Eye Movement”. This stage will begin approximately ninety minutes after you fall asleep. REM sleep lasts around ten minutes at first, after a few cycles, it builds up to last around an hour! During this stage, the heart rate will increase and your breathing method will become intense. Additionally, your eyes move very quickly in different directions. During REM, you have very sharp sensations... middle of paper ... Accidents have been reported due to drowsiness, and there have been approximately 1,500 deaths and 71,000 injuries. Sleep is an important factor in your daily routine and you need to make sure you get enough sleep. By doing this, you could save your life and many others. (National Sleep Foundation, 2014)Sleep is a very important aspect of your life. In fact, when the average person reaches the age of seventy-five, they have slept for twenty-five years of their life, and they dream about six years of it! (Jason Stahl, July 1, 2006) Sleep is necessary because it helps you manage your daily life. You also need sleep to avoid becoming depressed, gaining weight, being sleep deprived, and many other things. Sleeping is crucial to your body and your life, and that's why you spend so much time sleeping.