Sleep is a process that takes time to complete. It begins with stage one and goes to a deep sleep known as stage four. These stages are all during the time known as Non-REM sleep, or Non-Rapid Eye Movement sleep. The first stage is a very light sleep with relaxed muscles. The second is characterized by brain waves getting larger. The third and fourth stages are where the sleeper is in a deep sleep in which their brain waves are.
huge and slow which makes this stage the hardest to wake from. After an hour or so, you shift into a highly active stage characterized by rapid eye movements, hence the name REM sleep. Suddenly your brain waves are almost the same as if you were awake. You're in the dreaming stage, which occurs several times across the course of the night (Kryger).
Now, what happens when we're deprived of the restful sleep we need? We're less alert and attentive, more inclined to irritability and other mood problems. These emotional changes can cause our relationships with people to be difficult. Our concentration and judgment suffer, our ability to perform even simple tasks declines, and our productivity is sabotaged. Sleeplessness, whether it's the result of a sleep disorder or an overextended lifestyle, invites diminished quality of life and deteriorating health. When we lose sleep or our sleep is poor, we also put ourselves, and those around us at high risk for accidents. Major industrial catastrophes such as the Three Mile Island incident have been attributed to human error that occurred during times when the body is at its sleepiest (Horne). If we ignore our sleep needs and get behind the wheel of a car, lives may be at stake. It only takes a few seconds-just long enough for a tired body to steal a needed "micro-sleep"- to run off the road or into an oncoming car. .
In 1894 Dr. M. de Manaceine showed that totally depriving dogs of sleep led to their death.
