Browsing by Author "Kajanto, Kristiina"

Aims of the study. Evidence suggests that a slow breathing method called resonance frequency breathing may improve sleep quality, but many previous studies have suffered from methodological shortcomings. Music listening is a popular self-help strategy to promote sleep, but previous research assessing the efficacy of music in improving sleep has yielded inconsistent results. Sleep is known to promote the retention of newly learned material, but the effects of slow breathing and music listening on overnight declarative memory consolidation are unknown. This study explores the effects of two interventions, slow breathing approximating resonance frequency and music listening, on objective sleep quality and overnight declarative memory consolidation. Methods. This study was a randomized, controlled trial with a crossover design. 20 participants (10 females) were randomly allocated to an experimental group, who did a 30-minute slow breathing exercise, or a comparison group, who listened to relaxing music for 30 minutes. Participants’ sleep was measured on two consecutive nights with polysomnography. On one night, participants completed their assigned intervention before going to bed; the other night was used as a no-treatment control condition. Memory performance was measured with a word pair association task. Linear mixed-effects modeling was used to analyze the data. Results and conclusions. Slow breathing improved declarative memory performance, but it did not improve sleep quality when compared to the control condition. Music listening did not affect memory performance, but it improved sleep quality as manifested in reduced wake after sleep onset, decreased duration of stage N1, stage N2, and non-REM sleep, and an increased percentage of stage N3 sleep when compared to the control condition. The results suggest that music listening can improve objective sleep quality and slow breathing can promote overnight learning, but more research is needed to understand the exact mechanisms underlying these associations.