Sweat-soaked sheets. A racing pulse. An overpowering sense of dread.
For anyone who has ever had a true nightmare, waking up in the dark with these symptoms is a familiar experience. Now, new research out of the United Kingdom suggests that women are more likely to report having nightmares than their male counterparts -- a finding that would further confirm similar findings in past research.
Moreover, says lead study researcher Jennifer Parker, the new findings delve into the several different types of nightmares that people experience. Among them is the existential nightmare, in which the dreamer loses something or someone they love.
These dreams in particular, she says, were more commonly reported among women.
"I think it's a fairly well-established research finding that women report more unpleasant dreams than men," said Parker, a psychologist at the University of the West of England in Bristol. "But I don't think any previous research has picked apart the various differences you have in dreams, which allow different types of nightmares to emerge."
"'Nightmare' should not be used as a blanket term," she said.
Parker studied dream reports from 193 people -- 100 women and 93 men. What she found was that about 19 percent of men reported having had nightmares, while about 30 percent of women reported having them. And she says the type of nightmare reported -- as well as the psychological impact of the bad dreams -- differed between the genders.
"Existential nightmares appear to be far more disturbing for women," she said. "They are much more upsetting to women than the fearful nightmare, and many women wake crying from them."
Some sleep researchers, however, cautioned against reading too much into the results of the relatively small study.
"It is important not to over-interpret the finding of more recalled nightmares by assuming this means there are more of them actually happening," said Dr. David Rapoport, associate professor of medicine and director of the Sleep Program at the New York University School of Medicine. "We only remember a small number of the dreams -- and nightmares -- that are found when we are queried after an arousal."
Rosalind Cartwright, dream research and chairman of psychology at Rush University Medical Center, agrees. "This was a self-report survey. We know that ... nightmare frequency, when you collect the data in that way, is very different from when you log it every day."
But she adds that the new research once again demonstrates how women tend to have better recall when it comes to dreams, including disturbing ones. And she says this and other studies shed light on how women might "process" emotional occurrences in their day-to-day lives.
"It seems to be related to women being a little more inwardly oriented, paying more attention to their feelings, and being more self-critical," she said, adding that women would also be "more likely to carry [these feelings] into bed" and subsequently dream about them.
"We know that any experience from your waking hours that has an emotional tag is likely to be carried forward into sleep," Cartwright said.
The study is not the first to home in on particular demographic variables to try and separate those who are more likely to have nightmares from those who have a better chance of dreaming peacefully.