The average person spends around one-third of his or her life asleep. Through sleep, our bodies regain the chemicals required to stay active. While sleeping, the brain stays busy sorting, filing away and discarding thoughts and images gathered throughout the day. The process is similar to the de-fragmenting of a computer hard drive to make it run better. These involuntary successions of images, ideas, emotions and sensations are essentially our mind's attempt of relaxing and distancing itself from the everyday realm.
Cause: Stage of Sleep
Sleep involves four stages. The first stage is a light sleep. It usually only lasts a few minutes, and if the sleeper is undisturbed, he will quickly drift into the second stage of sleep. The second stage is a much deeper sleep than the first. This stage can last the entire duration of sleep. However, if the sleeper's muscles begin relaxing, they will enter the third stage of sleep. At this point, the sleeper's heart rate will slow down, his or her blood pressure will fall and breathing will become steady. Once the body accomplishes those three things, the sleeper will submerge deep into the fourth and final stage of sleep. This is the deepest form of sleep and the only time that dreams can occur. Your imagination runs wild during the fourth stage, chalking up short stories and vivid imagery. This is the state in which rapid eye movement begins. REM takes place multiple times during a deep sleep, but each time lasts only about 10 minutes. The sleeper will dream for the entire duration of stage four, but will only be able to recount the events of his dream if he wakes up during an REM cycle.
Most dreams are reflective of the experiences, thoughts or desires that the sleeper has had in recent awake time. They are most commonly subconscious thoughts of which the dreamer might not even be aware. However, if the person analyzes her dream immediately upon waking, she may be able to piece together reasons that it may have occurred.
Effect: Quality of Sleep
Dreams have a direct impact on the quality of sleep. If the sleeper is having a pleasant dream, his sleep will seem quicker than normal, and he will wake up feeling rejuvenated. If he is having a nightmare, his sleep will encounter multiple fear-induced wake-ups.
Effect: Mood of Day
Depending on the tone of a dream – be it sad, happy or angry – the ensuing morning's mood will be reflective of that. It can take a broad range of hours, depending on the person, to shake the negative effects of a sad or mad dream, while a good dream can leave a person glowing all day.