Improving night-time sleep with hypnotic suggestions

Abstract

Slow-wave sleep (SWS) is fundamental for maintaining our health and well-being, and SWS is typically reduced in stress-related sleep disturbances and age-related sleep disorders. We have previously reported that exposure to hypnotic suggestions before sleep effectively increases the duration of SWS during a midday nap in younger and older women suggestible for hypnosis.However, it remains unclear whether this beneficial effect of hypnosis on SWS can be generalized to night-time sleep and men. Therefore, we tested the effect of the hypnotic suggestions on SWS across an 8 hours night-time sleeping interval in 43 healthy young French-speaking subjects (19 males) of high and low suggestibility. In accordance with our previous results, listening to hypnotic suggestions before sleep increased the amount of SWS in highly suggestible subjects significantly by 13 min compared to a control condition in both genders. Particularly in the first hour, slow-wave activity was significantly increased after hypnosis as compared to the control night in high suggestible. The hypnosis-induced benefits on objective sleep parameters were also reflected in increased subjective sleep quality ratings. Our results demonstrate that hypnotic suggestions are an effective tool to deepen sleep and improve sleep quality also across a whole night of sleep in young healthy men and women. Our findings provide an important basis for the examination and potential application of hypnosis to improve deep sleep in populations with sleep disturbances.