We’ve all had them: nightmares, those dreams that cause us to jolt awake, heart racing and drenched in sweat. While there is no better feeling than waking up to realize a nightmare was nothing more than a dream, why does the mind manifest such outrageous fantasies, especially when they seem to have negative effects rather than positive ones?
What causes nightmares?
First and foremost, a nightmare is not different from a dream; ‘nightmare’ is simply the term given to a bad dream, and comes from ancient beliefs about evil spirits visiting the innocent while they sleep. Like all dreams, nightmares occur during rapid eye movement (REM) sleep, a period during the sleep cycle that immobilizes the body and increases protein production. REM sleep occurs approximately 90 minutes after first falling asleep and then again every 90 minutes throughout the night, eventually lasting longer as the night goes on, according to the National Sleep Foundation.
No one knows exactly why we dream, but experts have speculated dreams are the mind’s way of making sense of the random signals that occur during REM sleep when proteins are being made. Why we have good dreams rather than bad dreams or vice versa isn’t fully understood either, but the latest research suggests it is the mind’s way of focusing us on things we perceive as important in our lives. Millenniums ago, it was a survival mechanism, but now many nightmares are the result of dwelling on feelings like sadness, guilt, or anxiety.
“Nightmares probably evolved to help make us anxious about potential dangers,” Harvard researcher Deirdre Barrett told Live Science in 2010. “Even post-traumatic nightmares, which just re-traumatize us, may have been useful in ancestral times when a wild animal that had attacked you, or a rival tribe that had invaded might well be likely to come back. With the modern dangers of house fires, car crashes, rapes and muggings unlikely to repeat soon for the same victims, this adaptive mechanism doesn’t always serve us well,” Barrett explained. “However, some nightmares may be calling to your attention something you might do well to worry about or something that, once you are more conscious of the concern, you can convince your unconscious to stop wasting time on.”
Other facts about nightmares
Though we can dismiss nightmares as just frightful dreams, our lack of understanding has led to some intriguing truths that have yet to be fully explained. For example:
- Fear is not the most common emotion in a nightmare; rather, confusion, guilt and sadness are most common. What’s more, these emotions tend to stick with you longer than if your dream is fear-based.
- Health Central indicates 5 to 6 percent of people have nightmares so terrifying and frequently they develop a type of insomnia to avoid falling asleep.
- Physical aggression is the most reported theme in nightmares.
- Research from Carnegie Mellon University found having a nightmare about an upcoming event (like flying on a plane) was enough for most people to justify making a change in travel plans.
- People who stay up late are more likely to have nightmares compare to those who go to bed early.
- Being too warm at night can trigger nightmares. Experts suggest the reason for this is because heat triggers the body’s fight-or-flight response, a mechanism linked to survival and heightened anxiety/anticipation.
- People who play video games frequently are more likely to be able to turn a nightmare into a regular dream during sleep.
Though nightmares aren’t something to dwell on or waste time being upset about, if you are having nightmares frequently and they are disrupting your everyday life, pay a visit to your doctor. You may be suffering from an underlying disorder, like post-traumatic stress disorder.