The science behind dreams; What is a dream and why do we have them.
The waking world does impact the dreams, and sometimes you'll dream about things which have happened years ago or even things you didn't know you remembered. It's not an exact science and much is yet to be discovered.
In terms of the actual sleep itself, what we know is that the brain undergoes several changes during the night. You start off with light sleep during which you are still fairly alert and aware, any loud or soft noises will wake you and cause you to sit up. during this stage, the brain produces Beta waves, which are small and fast waves, typical of being awake or still alert.
You then enter a short stage of sleep for about 10 minutes in which the brain produces Theta waves. These are very slow brain waves. After this, there is a stage of sleep called Stage 2 sleep. During this stage, the brain waves are short rapid bursts of
rhythm called Sleep spindles, and also during this stage, the body temperature decreases and heart rate begins to slow down.
After this, The body enters Delta wave sleep, or Stage 3 sleep. The temperature is drastically lower, heart rate slowed and breathing deep and controlled. The body is preparing for deep and long sleep. Next is stage 4 sleep, officially called Delta sleep, which is a deeper period lasting 30 minutes.
After stage 4 comes the most important to Lucid Dreaming, REM sleep. REM means Rapid eye movement, and is where the brain becomes very active, the most likely time to have vivid or lucid dreams is in REM sleep. It's an unusual part of sleep because as the mind becomes more active, the muscles become more relaxed and paralyzed, meaning that there are times when someone can wake up during REM sleep, for example if they had a vivid nightmare, and yet still be stuck to their bed and unable to move.
This can be quite scary for some people, but sleep paralysis is normal and nothing to be worried about. Now that you have a basic understanding of a dream how it works and why we have them, have a look at the next section; Understanding your dreams.. dream meaning.