If you want to avoid having nightmares like these, it might be best to get less than 9 hours’ sleep a night.
People often have nightmares following upsetting events, and research into nightmares has mostly focused on people with conditions like post-traumatic stress disorder (PTSD). But most people get nightmares at some point, prompting Stephanie Rek at the University of Oxford and her colleagues to perform one of the largest ever studies of nightmares in the general population.
The team recruited 846 people through media advertisements and databases of people interested in sleep studies, and asked them to complete an online survey. The participants were asked questions such as how many nightmares they had experienced over the past two weeks, and how bad they were. These answers contributed to an overall score on a “nightmare severity scale”.