All mammals dream. The most vivid and memorable dreams take place in REM (Rapid Eye Movement) Sleep. The eye movements correspond with the dreamer looking around and seeing things in the dream. The rest of the body is paralyzed at the brain stem.
The sleep and dream cycle varies between individuals, but the majority of health people show a consistent pattern illustrated by the graphs above.
The Circadian Rhythm is a 24 hour cycle that the human body goes through each day. Within this day and night cycle there is a 6 to 10 hour period in which we sleep. This sleep period includes both deep sleep, and REM sleep.
Every 90 to 110 minutes, the human body goes through an Ultradian Rhythm. This cycle is most apparent while we sleep because each cycle includes a period of deep sleep, and a period of REM sleep. At the end of each Ultradian Rhythm, there is a short period of wakefulness when the person can adjust their sleep position before falling back into sleep. Each subsequent ultradian rhythm requires less deep sleep, and so the REM period becomes longer.
A person will experience a higher degree of dream recall when they are healthy, go to sleep at the same time each night, and wake up naturally after a full night of sleep. The person must also have an interest and curiosity for their dream experiences each morning upon awakening. It is recommended to write dream experiences in a dream journey to strengthen retention.
Sleep and dream cycles varies between individuals, but the majority of healthy people show a consistent 90 minute cycle illustrated by the pie graph to the left. The Red areas represent REM (Rapid Eye Movement) Sleep. The eye movement happens when the dreamer sees and interacts with dream content. These are the times when dreams are the most vivid. Particularly the last REM period in the morning of a good night sleep.
The key is to wake up after a REM period, and recall the dream that just took place. If you fall back into deep sleep (The Grey areas), you will loose the memory of the dream. This is why writing down your dreams upon awakening is so important.
Waking up multiple times in the night can be good for your dream recall. A way to facilitate this is by setting up 2 morning alarm clocks. One that goes off 2 hours before you normally wake up. By waking up to full consciousness, then going back to bed, you increase the likelihood of being full conscious in your dream, and becoming lucid. This technique is often refereed to as "Wake-back-to-bed."
If you have never done that before, I recommend you try it tonight. Go to bed a little earlier than normal, and set a 2nd alarm clock to go off 2 hours before you need to get up. When you wake up early, consider that you could be dreaming right now, and that you will be in 90 minutes or so. You may be surprised at how much more vivid your dreams become.
