By Alan Mozes
THURSDAY, June 19, 2014 (HealthDay News) -- A short session of hypnosis might lead to a better night's sleep, says a team of Swiss researchers.
After listening to a sleep-promoting audio tape containing hypnotic suggestion, women who are suggestible to hypnosis spent two-thirds less time awake, and about 80 percent more time in deep sleep compared to those who slept without the hypnotic suggestion.
"There have been many reports that hypnosis can be a good thing for promoting sleep," said study co-author Bjorn Rasch, a professor with the department of psychology in the division of biopsychology and methods at the University of Fribourg in Switzerland.
"However, usually they've been based on people just subjectively indicating how well they feel they've slept as a result," Rasch noted.
The new study is the first to assess via measures of brain-wave activity "the positive impact hypnosis has on deep sleep and to show that it is, in fact, real," he said.
At issue is the desire to boost so-called deep sleep, also known as slow-wave sleep.
This type of sleep "often correlates with the most restorative sleep -- it's a time for your brain to process and rejuvenate from the challenges of the day," explained Dr. Kim Hutchison, assistant professor of neurology and sleep medicine at the Oregon Health and Science University in Portland.
"Over the course of people's lives, with age, the amount of deep sleep drops off significantly. And by the time you're 50 or 60 you hardly have any, depending on the person," said Hutchison, who was not involved in the new research. "With age, non-refreshing sleep becomes a very common complaint, and one of the reasons can be not getting enough slow-wave sleep."
To explore how hypnotic suggestion might help improve deep sleep, the Swiss team enlisted 70 healthy Swiss women aged 18 to 35. All participated in a series of five in-laboratory experiments, successively staged once a week for five weeks.
None of the participants had any history of sleep trouble. None were taking any kind of sleep medication. Some of the women, however, were deemed (in pre-study testing) to be "highly suggestible" to hypnosis, while others were categorized as "low suggestible" patients.