This is why you keep having nightmares

If you experience too many nightmares lately, you might want to cut down on your sleep and get less than 9 hours a night.

People often get nightmares after upsetting events, which is why research into nightmares has focused on people with conditions like post-traumatic stress disorder (PTSD). However, most people get nightmares, which is why Stephanie Rek at the University of Oxford and her colleagues decided to perform one of the largest ever studies regarding nightmares in the general population.

The team recruited 846 people via social media advertisments and databases and asked them to complete an online survey. The participants were asked how many nightmares they had experienced over the past two weeks and how bad they were, as well as other aspects of their life, like recent divorces or legal trouble, tendency to work, how much alcohol they drink and how much sleep they get.

One of the conclusions was that worrying about the future or about doing things wrong was most strongly associated with the frequency and severity of nightmares, as New Scientist reports. The research suggests that worrying before bedtime feeds negative dream content and thus increasing the chance of having nightmares.

A link between the occurence of nightmares and sleeping more than 9 hours a night has also been found. According to Rek, sleeping for longer periods of time might increase the amount of late-night rapid eye movement (REM) sleep, the time when nightmares usually occur.

Whatever the relationship between worrying, nightmares and too much sleep is, it might be possible to intervene. “For example, worry can be effectively treated using cognitive behavioural approaches,” Rek said. “It would be interesting to do more research to see whether these alleviate nightmares.”