Interindividual differences in mindfulness are linked to sleep-EEG characteristics.

Abstract

Mindfulness describes the ability to focus on the presence, including one's thoughts and feelings. Trait mindfulness - a person's inherent tendency to be mindful - has been connected to increased subjective sleep quality, but evidence from objective EEG-based sleep measures is lacking. Here, we investigate whether objective EEG-based sleep parameters explain interindividual differences in trait mindfulness. Whole-night polysomnographic data were gathered from 52 healthy adults (27 females; agemean = 21.5 (SE = 0.28)) in their home using a portable high-density EEG-device. Trait mindfulness was assessed using the Five Facet Mindfulness Questionnaire short form (FFMQ-SF). Trait mindfulness was positively correlated at trend-level with the percentage of REM, but not N1, N2 or SWS. Additionally, those exhibiting less REM beta/gamma power and NREM beta power displayed higher trait mindfulness and vice versa. Lastly, we replicated findings connecting higher trait mindfulness to better subjective sleep quality. REM sleep is pivotal for emotional processing. Decreased REM high-frequency activity was suggested to reflect adrenergic reduction that defuses affective experiences. Increased NREM high-frequency activity is a marker for cognitive hyperarousal in insomnia. We speculate that differences in trait mindfulness might be explained by differences in REM- and NREM-sleep functions that promote ideal emotional regulation and prevent hyperarousal.