A new study has uncovered a link between nightmares and too much sleep.
According to Quartz, "...researchers from the University of Oxford found that those reporting more than nine hours of sleep a night were 40% more likely to have nightmares than those who...slept for shorter amounts of time."
One of the paper's authors, Stephanie Rek, has indicated that this may be caused by an extended amount of REM sleep—a phase where the brain is active and dreaming typically takes place.
The study involved 846 U.K. participants who filled out an online survey about the frequency and severity of their nightmares in addition to other factors like sleep duration, stressful life events, and symptoms of PTSD, or post-traumatic stress disorder.
Based on the team's assessment, some of the lifestyle behaviors like alcohol did not appear to have an influence on bad dreams.
However, sleep duration did, as did other variables like worry, hallucinatory experiences, and paranoia. As such, Rek has said that therapy may be able to help in some cases but more research would be needed.
Stress has also been cited by the National Sleep Foundation as a common contributor to nightmares in addition to eating before bed, medications, and sleep disorders.
Ironically, the foundation also lists lack of sleep as a potential cause and recommends that people keep their rooms cool and wind down at night to increase sleep time.
RELATED: Common dreams and their meanings
Common dreams and their meanings
Common dreams and their meanings
1. You're falling from the sky
We've all had this dream, where you wake up flinching in your bed. The feeling is all too realistic.
Falling means you're nervous something is going to spiral out of control. Psychologist William Braun explains this feeling of free-falling is "associated with feeling out of control or overwhelmed. They may also relate to feeling unsupported and insecure".
2. You're unprepared for a test
It's such a horrible feeling. It's right before a huge exam, and you show up, and your mind goes blank. Or there's a test you just had no idea about. It's life or death.
It's gross, and if you're unlucky enough to remember your dream, your first instinct is to touch your mouth and make sure your teeth are still intact.
Like many other dreams, teeth flying out is yet another symbol of anxiety. In times of big changes and transition, "We might think of this as being concern about one's potency, competence, strength, power, ability to 'take a bite out' of the world," said Braun.
4. You're being chased
It's more than a dream, it's a nightmare.
While being chased is a pretty popular dream, it's meaning varies on the context.
In a nutshell, it means you're nervous to confront an issue, and thus you keep avoiding it. If a monster is chasing you, it be an indication that you're avoiding a big problem -- like an addiction or a chasm in your relationship.
Even if you don't recognize the person who is chasing you, the dream has implications. "Keep in mind, people in dreams can be substitutions for other people or even substitutions for aspects of ourselves," Braun said.
5. You're naked in public
Being naked in front of a crowd, when everyone else is dressed, relays a sense of vulnerability and innocence. "These dreams are often accompanied by feelings of embarrassment and shame," Braun said. Furthermore, it could mean "this person wants to be seen, acknowledged, admired."
6. You need to scream out, or you can't move
It's really scary when you need to use your voice to ask for help, or something is coming after you but you are immobilized.
However, Braun explained that it "may not just be a dream, but may be the result of sleep paralysis." During REM sleep, you're essentially paralyzed as to not move and hurt yourself when we dream. So, according to Braun, if you wake up from sleep paralysis, it's usually before the REM cycle. It's merely you experiencing this as a dream state.