Night owls may have more nightmares

Like burning the midnight oil? A new study reveals an unexpected dark side to staying up late: night owls may have more nightmares.

About 80 percent of adults experience at least one nightmare a year, but a new study suggests that a late-night lifestyle could trigger more than its fair share of bizarre or frightening dreams.

The new study from Yuzuncu Yil University in Van, Turkey, surveyed 264 university students about their sleep habits and frequency of nightmares, with the participants rating the intensity of their dreams using a measure called the Van Dream Anxiety Scale. The study was published last week in the journal Sleep and Biological Rhythms.

The reason why staying up late produces more nightmares is unclear, but experts cite a possible connection to the stress hormone cortisol. The hormone typically peaks in the body in the morning at around the same time REM sleep cycles spike.

"The idea is that if your sleep has been shifted you may be asleep when cortisol is elevated, which might lead to nightmares or bizarre and vivid dreams," said sleep expert Jessica Payne from the University of Notre Dame in the US (she was not involved in the study), in an interview with health news website LiveScience.

LiveScience also cites another larger online study of 4,000 people that found a link between staying up late and nightmares among women in their 20s.

If you suffer from nightmares, health web site WebMD cites that stress could be playing a role. A surefire stress buster? The site recommends exercise, or try yoga, meditation, or deep abdominal breathing.