It was once thought that when you slept, your brain simply shut off, and that it was inactive until you woke in the morning. It wasn’t until the late 1920’s that scientists had the technology to read brain activity and monitor it. They discovered during this time that the brain is actually very much awake and at times, highly active; sometimes even more active at night than during the day! They also discovered that there are two main types of sleep; REM (rapid-eye movement) and NREM (which you’ve probably guessed is non-rapid eye movement). We go through a cycle each night of light sleep (also referred to as NREM) followed by deep sleep (REM); most of us remember our dreams much better when we’re awakened during our deep sleep cycle. One cycle can last about an hour and a half and will repeat itself over and over throughout the evening. During REM your leg and arm muscles actually become paralyzed, which scientists assume is a safeguard against actually acting out our dreams.
We’re still not entirely sure why we dream, but there are a few theories. One suggests that dreaming is a way for our brains to sort all of the data it’s collected all day long. Because our brains process millions of pieces of information (even when we’re not aware of it), dreaming might be a way for our brains to decide what to retain and what isn’t important enough to hang onto. Studies have shown that when we learn new things we tend to dream more; during one particular dream study, those participants who were learning a new language displayed more dream activity than those who were not. It may very well be that while the students dreamt, their brains were hard at work ensuring that the new language was headed to long term memory while the less important pieces of information were tossed aside.
There is another theory that dreams are a reflection of our emotions. While we go about our normal daily routines, our brains are hard at work processing everything down to the tiniest detail. Let’s say you’re building a garden bed frame. Your brain is not only focused on the design and which tools work with each step, it’s also sending signals to your body; a signal for your fingers to grab the hammer, for example, and for the other hand to grip that nail tight! Since during the evening hours while we’re sleeping our brain has the chance to slow down, it also has the chance to wade through all of the emotions that maybe we’d been too busy to recognize during our busy waking hours. A common dream brought on by stress is one of losing your teeth. This is often a case of feeling powerless or having lost control of a situation. Especially during times of high stress or worry, you may find you have more dreams relating to your situation; even if only in a symbolic manner.