We’ll leave it to Sigmund Freud and other professional psychologists and psychiatrists to interpret dreams, but the effect of dreams on sleep is an important issue for all of us. In short, do dreams influence the quality of our sleep (leaving aside the issue of nightmares, which of course do interrupt our sleep)?
There are basically five stages of sleep, but dreams are largely confined to the REM, or rapid eye movement, phase of sleep. While mammals and birds also exhibit REM sleep patterns, reptiles and cold-blooded animals do not.
According to the National Institutes of Health (NIH): “REM sleep begins with signals from an area at the base of the brain called the pons. These signals travel to a brain region called the thalamus, which relays them to the cerebral cortex – the outer layer of the brain that is responsible for learning, thinking, and organizing information. The pons also sends signals that shut off neurons in the spinal cord, causing temporary paralysis of the limb muscles.”
So in REM sleep, we are also in a type of paralysis, and if this paralysis doesn’t occur for whatever reason, a deadly acting out of our dreams can take place. For instance, if you dream about swinging a bat at a baseball game, you may get out of bed and “act out” the swing — and perhaps knock a lamp over. The paralysis, then, is an important safety feature for our REM sleep and dreaming.
Sleep generally occurs in 90-minute phases repeated throughout the night. Each phase moves from non-REM sleep to REM sleep. At the beginning of the sleep cycle, the REM phase lasts only a few minutes, but in the last phase before awakening, the REM phase can last up to 40 minutes, and these late-stage dreams often stay in our memories as we awaken.
Whatever the function of dreams — Freud called them a “safety valve” — the presence of dreams indicates that your sleep cycle is functioning properly. However, sleep deprivation leading to dream deprivation only increases the number of dreams and time spent dreaming when you sleep again.
“When someone is sleep deprived we see greater sleep intensity, meaning greater brain activity during sleep; dreaming is definitely increased and likely more vivid,” says neurologist Mark Mahowald of the University of Minnesota and director of the Minnesota Regional Sleep Disorders Center in Minneapolis.
The bottom line, then, is that dreams (which are often repetitive and occur in cycles throughout the night) signify that you’re definitely entering your REM cycle. The overriding question, then, is — are you getting the proper amount and quality of sleep? To gauge that, you only need examine how zestful or fatigued you feel the next day.
We didn’t resolve much here about how dreams affect our sleep, but rest assured that if you get your proper night’s rest, your experience will be filled with dreams.