A very frequently asked question for which there remains an elusive answer is “why do we dream”?
While many theories are out there, none are proven.
Let’s start with what we do know.
First, Why Do We Sleep?
I think this is best summed with a somewhat nebulous answer; quoting directly from the National Institutes of Neurological Disorders and Stroke, “Everyone needs sleep, but its biological purpose remains a mystery”.
In researching this question, you will find publications from major Sleep Institutions to the most basic blog post and the conclusion remains the same; we really don’t know, but we do know that we don’t function well without it and that multiple systems are affected adversely by chronic sleep deprivation. Risks of diabetes, stroke, high blood pressure, obesity and mood disorders and many more health concerns are increased in individuals with insufficient or disrupted sleep.
Sleep was not really investigated until the early 20th century and it wasn’t until the early 1950s that Rapid Eye Movements were observed during the sleep cycle and soon after linked to our most vivid dreams. At the time, it was a startling discovery that the brain remains active during sleep, and nearly as active during the REM phase as it is in the waking state.
Just as the body’s other processes of elimination and detoxification occur during rest, it does appear that the brain detoxifies, eliminates waste and reorganizes itself during sleep as well.
Rather Than Ask Why, Ask “What Happens When We Don’t?”
What we do know for certain is that people function better on a cognitive level with adequate sleep; the ability to learn and process new information is markedly enhanced. We both comprehend information better after we have had a good night’s sleep and we remember new information better when followed by a good night’s sleep, so part of sleep’s function is to help us store memory and retain it.
Other things that are affected when we don’t sleep well include our processing speed, our physical reflexes, coordination, emotional balance, dexterity, and even our judgement. In other words, individuals claiming to function well on less than the average # of hours of sleep may actually be deceiving themselves. Judgement can be markedly impaired by chronic sleep deprivation, yet the affected individual may not perceive their own impairment; consequences from chronic sleep deprivation can be very grave indeed.
In Catastrophes, Sleep and Public Policy: Consensus Report, it reads “Perhaps most disturbing is the fact that the nuclear plant catastrophe at Chernobyl is officially acknowledged to have begun at 1:23 a.m. as the result of human error (39, 40).” The citations are linked to the International Nuclear Safety Advisory Group and the U.S. Nuclear Regulatory Commission and evidence suggesting that this disaster among the many other industrial and engineering accidents cited within this consensus report was that the timing of the incidents were coincident to hours of operation when levels of alertness and responsiveness could have been compromised and in workers that had reported compromised restorative sleep between shifts. The Three Mile Island and Challenger disasters were among some of these analyzed and the conclusions and recommendations of this report strongly urged conscientious attention to policies and performance with appropriate intervals of rest as critical to matters of public safety, as long shift hours and insufficient sleep could not be proven as causal but were definitely linked.
There are societal risks as well that can affect anyone, but most especially our youth. “Poor sleep can negatively affect a student’s grades, increase the odds of emotional and behavioral disturbance” is the title of an abstract submitted at SLEEP 2008, the 22nd annual meeting of the Associated Sleep Professional Societies and is among countless articles that link ADHD and other barriers to learning to aberrant sleep in teens and young adults.
That abstract was presented in 2008.
In the 12 years that have followed this report, children, teens and adults have far more barriers to good sleep, including increased access to cellular phones and on-line activities that can further disrupt regular sleep routines both through excessive use and simply the added light stimulation. Light interferes with release of the natural hormone melatonin which occurs in response to natural changes from light to dark as night falls.
Thus, why we do not know all the reasons why we sleep, some of our modern technologies may have come at a tremendous cost. While we may not have all the answers, we absolutely do understand that sleep is necessary for our safety, optimal function at work, emotional well-being, decision-making and in navigating through this life without bumping into anything.
When Do We Dream?
We can dream at any phase of sleep, although the content and form of the dreams are different depending on which phase of sleep we are in. Our most vivid dreams occur during the REM phase (Rapid Eye Movement=REM), a sleep phase also observed in mammals such as dogs and cats.
There are multiple stages of the sleep cycle; ideally we experience 4-5 of these cycles per night for restorative sleep. Stages 1-4 are Non-REM cycles. During these, our brain waves progressively slow; Stage 1 is very light sleep and the sleeper can be easily aroused. Stage 2 is deeper and the body temperature drops, there is predominantly theta brainwave activity with bursts of brain activity. Stage 3 and 4 are progressively deeper stages of sleep with delta brainwaves, which are the slowest and last longer during the first few cycles of sleep. It is this last phase of deep sleep that is most critical to restorative sleep, as waking a person up during this phase will produce the most grogginess. Ironically, it is also during this phase of sleep that sleepwalking occurs; anyone who has lived with a sleepwalker knows that while they may look wide awake, it is best not to disturb them if possible.
In REM, our brainwaves pick up, particularly in the thalamus, which serves as a relay center transmitting sensory information to the brain which produces the more vivid dreams characteristic of the REM cycle. These are often not recalled unless the dreamer is awakened while still in REM, which is why it is helpful to write down the content of a dream immediately upon awakening.
Cycling through these phases takes on the average 90 minutes with some variability and we spend more time in REM as the night progresses. (If you are interested in tracking your sleep cycles, click on the image shown*).
Thoughts on Why We Dream
There are many; included below are some of the most commonly accepted hypotheses with considerable overlap:
- We are expressing subconscious desires that we couldn’t express in a socially acceptable manner in the waking state.
- We are preparing for action in our waking life (e.g., practicing flight-or-fight)
- We are needing to confront a subconscious emotional issue that we have not acknowledged to our conscious self
- We are storing important memories and clearing those no longer needed
- We are processing information (e.g., solving a problem with the solution more accessible on awakening)
- We are accessing our creative self (e.g., many writers and musicians will state their work was the result of a dream)
- We are experiencing a health issue or having a reaction to our diet and medications
While definitely not true of all dreams, there is one hypothesis that statistics demonstrate can and has occurred:
- We are getting a preview of coming events (a precognitive dream)
- We are receiving remote information about another person and their current state
Why that last bit? We invite you to read the story that follows by clicking here.
*As an Amazon Associate I earn from qualifying purchases.