Less Sleep Means More Dreams
Missing sleep tonight may just boost your dreams tomorrow night.
Dreams are amazingly persistent. Miss a few from lack of sleep and the brain keeps score, forcing payback soon after eyelids close. "Nature's soft nurse," as Shakespeare called sleep, isn't so soft after all.
"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
The phenomenon is called REM rebound. REM refers to "rapid eye movement," the darting of the eyes under closed lids. In this state we dream the most and our brain activity eerily resembles that of waking life. Yet, at the same time, our muscles go slack and we lie paralyzed—a toe might wiggle, but essentially we can't move, as if our brain is protecting our bodies from acting out the stories we dream.
Sleep is divided into REM and four stages of non-REM; each has a distinct brain wave frequency. Stage one of non-REM is the nodding off period where one is between sleeping and waking; it's sometimes punctuated with a sensation of falling into a hole. In stage two the brain slows with only a few bursts of activity. Then the brain practically shuts off in stages three and four and shifts into slow-wave sleep, where heart and breathing rates drop dramatically.
Only after 70 minutes of non-REM sleep do we experience our first period of REM, and it lasts only five minutes. A total non-REM–REM cycle is 90 minutes; this pattern repeats about five times over the course of a night. As the night progresses, however, non-REM stages shorten and the REM periods grow, giving us a 40-minute dreamscape just before waking.
In a 2005 study published in Sleep, Nielsen showed that losing 30 minutes of REM one night can lead to a 35 percent REM increase the next night—subjects jumped from 74 minutes of REM to a rebound of 100 minutes.
Nielsen also found that dream intensity increased with REM deprivation. Subjects who were only getting about 25 minutes of REM sleep rated the quality of their dreams between nine and eight on a nine-point scale (one being dull, nine being dynamite).
John Antrobus, a retired professor of psychology and sleep research at the City College of New York says that dream content is tied to our anxieties. But he never found the extreme vividness in REM rebound that others assume is there, based on a higher level of brain activity which likely means more action-packed dreams.
"The brain is an interpretive organ, and when regions are less connected as they are in sleep, we get bizarre narratives," he says. "But its purpose? For that we have to ask what is the purpose of thought. We can't answer one without answering the other."
Kemo D. (a.k.a. no.7)