'Night owls more likely to experience nightmares'

Washington, Sep 6 - If you think staying up late in the night is a real hoot, think again -- it has a sinister side too, as night owls or those who hit the sack late are more likely to experience nightmares, a new study has found.

 Past studies have estimated that 80 per cent of adults experience at least one nightmare a year, with 5 per cent suffering from disturbing dreams more than once a month.

But the new research, published in the journal Sleep and Biological Rhythms, found that those who go to bed late during the week but sleep more on weekends might experience more REM sleep -- a phase that is characterised by rapid eye movement, increased brain activity and vivid dreaming.

It's a very interesting preliminary study, and we desperately need more research in this area, says Jessica Payne, director of the Sleep, Stress and Memory Lab at the University of Notre Dame, commenting on the new findings.

For the study, a team at the Yuzuncu Yil University in Van, Turkey, surveyed 264 university students about their sleep habits and frequency of nightmares, defined as Òdysphoric dreams associated with feelings of threat, anxiety, fear or terror.Ó The team, led by Yavuz Selvi, used a measure known as the Van Dream Anxiety Scale to assess the rate of bad dreams.

Specifically, study participants were asked to rate their frequency of experiencing nightmares on a scale from zero to four, corresponding to never and always, respectively.

 On average, individuals who described themselves as evening types had a score of 2.10, whereas their morning-type equivalents averaged 1.23 on the scale, a significant difference according to the authors of the study.

 Exactly why evening types might report more nightmares is a mystery. But the authors believe that they might be more likely to have mood disorders and stressful lifestyles.

A so-called stress hormone known as cortisol might also be involved, Payne hypothesised. The hormone usually peaks in the body in the morning, just before we wake up. It's also around this time that REM sleep cycles also peak.