For as long as people have been able to communicate with one another, we’ve been asking the question, “Why do we dream?” Scientists and sleep experts have pondered this subject long and hard, and are still attempting to sort out fact from fantasy when it comes to dreaming. The one thing that we know for sure about dreaming is that it happens during one of the five stages of sleep. Called the “rapid eye movement” or REM stage, we typically enter it about an hour and a half after we fall asleep, and it is characterized by the eyes moving back and forth quickly behind the eyelids. During REM sleep, breathing is irregular and blood pressure levels rise. Scientists have discovered that with the exception of our bodies remaining still, REM sleep shows many of the same physiological attributes that appear when a person is awake. Although REM sleep only makes up one-fifth of the time that we spend asleep, sleep experts have a theory that it plays a specific role in our health and well-being. Dreaming is believed to help brain function by stimulating the regions that control memory and learning. Sleep studies have been done by the National Institutes of Health that indicate that dreaming is a way for us to organize our thoughts. It has been shown that during the REM stage, the brain picks out past images and information to “file it away” in the appropriate place in our minds. This fits in with the theory that what we dream about is actually a reprocessing of what we did throughout the day, no matter how strange the dreams are or how much they differ from the reality of our daily activities. It has also been shown that the body enters a state of temporary paralysis while we dream, in order to prevent us from acting out what we do in our dreams. When this safety mechanism malfunctions, issues such as sleep walking and talking occurs – these are known as parasomnias. One of the most common parasomnias is narcolepsy, which causes a person to be overly sleepy during the day and have very vivid dreams while they sleep. Those with narcolepsy sometimes have such realistic dreams that they confuse them with reality. People that suffer from any form of parasomnia may be unable to stay in the REM stage of sleep, which can cause them to experience what is known as “dream deprivation.” This can have some pretty serious side effects, including irritability, difficulty concentrating, and even the tendency to hallucinate. These discoveries about dreaming and REM sleep have only been made in the last two centuries. Before that, the history of the meaning of dreams is intriguing and varied. In the time of Plato and Aristotle, it was thought that people visited the “spirit world” while they dreamed. During the 19th century, many believed that dreaming was a way for us to live out our unconscious desires while we slept. Although we still don’t have a concrete reason as to why we dream, scientists believe that it is something that we all do – even if we don’t remember it when we wake up in the morning. Why do you think we dream? We’d love to hear your thoughts in the comments section!