Sometimes we remember them—sometimes we don’t. Sometimes they’re amazing—sometimes they’re awful. Dreams and our recollection of them really run the gamut and depend on a variety of factors, not all entirely known. And in fact, most are unknown. So, what do we know about dreaming?

What is dreaming, really?

Society has pondered this question for centuries with many philosophies coming into and out of vogue depending on the era. People have often cited dreams as being significant in their creative lives, offering inspiration and ideas. Others have talked about dreams providing a form of therapy. And some have underlined the increased activity of the amygdala in our brain as evidence for dreaming’s work preparing us for threats.

The start of the therapeutic theory began as far back as Ancient Greece, when Aristotle and Plato put forward the idea that our dreams provided us the opportunity to enact our unconscious or subconscious desires in a place, albeit imagined, without repercussions of real life. Psychoanalysts in the 19th and 20th centuries furthered their belief in this hypothesis, and even to this day, there are many who still believe this simply because we have been unable to learn that much more about sleep.

In 1953, though, doctoral researchers discovered what we call REM sleep—a.k.a. “rapid eye movement” sleep—which is when we dream. The two parts of our sleep cycles are now classified as REM sleep and non-REM sleep, and during REM sleep, our muscles are still inactive, but our brains at this point in the cycle kick into high gear, ramping up cognitive activity. In contrast, during non-REM sleep, which is the deep sleep phase of the cycle, cognitive activity and eye movement goes way down. The researchers conducting the 1953 study discovered that dreaming and REM sleep were linked because in waking their study participants, they found that those who were woken up during REM sleep recalled detailed, vivid dreams, whereas those who were woken up during their non-REM cycle barely recalled dreaming at all.

Why do we dream?

The question of why we dream, though, and what in our body makes dreaming happen is largely, and perhaps surprisingly, still up in the air. Dreaming is incredibly difficult to study, considering that the only person who can see what’s happening in a dream is the person who’s dreaming. On top of that, we forget much of our dreams when we wake up, so it’s even difficult to track what things our brains are jumping to and make connections between them after we’ve woken up.

And yet, researchers over the years have posited a few promising theories. One theory is that our dreams are simply the result of the increased neuronal activity in REM sleep—and not to be the cause for other meaningful conclusions. However, there is another theory that posits the exact opposite: that dreams serve as the means through which our brains process memories and emotions and find solutions to our problems. Under that theory’s umbrella, dreaming plays a significant role in our psychological and emotional wellbeing.

How does dreaming affect our sleep?

Like all things with dreaming, how it fully affects us and our sleep is still mostly unknown. But we do know that there are negative effects when we’re prevented from dreaming, or when our dreaming is cut off. In a 1960 study conducted to help determine the psychological effects of dreaming, Dr. William C. Dement (who just passed in June of this year) woke up study participants at the very beginning of their dreaming phase of sleep. The effects were clear: Participants exhibited increased anxiety, irritability, and tension. Many also experienced difficulty concentrating, changes in appetite and weight gain, reduced motor skills, symptoms of depression, and even hallucinations.

While these damaging results significantly affect our waking hours, science has yet to uncover the specifics of how it affects us in sleep. That said, we know and have discussed in earlier posts that it is critical for our overall health to get ample amounts of both REM and non-REM sleep. As indicated above, the negative side effects that occur when you do not finish out the REM cycle can be vast and detrimental in the long term for both our physical and mental health.

The other side of dreaming

However, not all dreams paint rosy pictures, and they can even indicate and/or contribute to other adverse conditions. Nightmares and night terrors, for instance, are not only unpleasant to experience (to put it mildly), but they also typically point to broader concerns, such as sleep apnea, depression, or other psychological trauma. Furthermore, they can in fact heighten symptoms of depression and anxiety, fatigue, and insomnia. If you are experiencing consistent bad dreams or insomnia, it might be time to talk to your doctor to learn if there are other factors involved.

While time and research have proven inconclusive on the big questions surrounding our dreams, rest assured (see what we did there?) that dreaming—and getting enough sleep and dreaming—plays a vital role in our overall health and well-being.

Do you remember your dreams? How have they affected you?