Every night, while your body rests, your brain is busy telling you stories. Most people dream for about two hours each night, even if they remember nothing in the morning. But why do we dream at all? Scientists still do not have a final answer, but they have learned a lot.
Sleep happens in cycles that last about ninety minutes. In each cycle there is a stage called REM, which stands for Rapid Eye Movement. During REM sleep, the eyes move quickly under the eyelids, the brain is almost as active as when we are awake, and most of our vivid dreams happen. At the same time, most of the muscles in the body cannot move. This is probably a protection: it stops us from acting out our dreams.
One popular theory says that dreams help us deal with memories. During sleep, the brain sorts the events of the day, keeps what is important and throws away the rest. Another theory says that dreams help us handle emotions. When we dream about something frightening, such as an exam or a fight with a friend, we may be practicing how to deal with it in a safe place.
Why do we forget most of our dreams? Researchers believe that the parts of the brain that store new memories are less active during sleep. If you want to remember a dream, try writing it down the moment you wake up. Within a few minutes, most of it will be gone.