The Effects of Presleep Slow Breathing and Music Listening on Polysomnographic Sleep Measures - a pilot trial

Knowledge on efficient ways to reduce presleep arousal and, therefore, improve sleep, is scanty. We explored the effects of presleep slow breathing and music listening conditions on sleep quality and EEG power spectral density in young adults in a randomized, controlled trial with a crossover design. Participants’ (N = 20, 50% females) sleep was measured on two consecutive nights with polysomnography (40 nights), the other night serving as the control condition. The intervention condition was either a 30-minute slow breathing exercise or music listening (music by Max Richter: Sleep). The intervention and control conditions were placed in a random order. We measured heart rate variability prior to, during and after the intervention condition, and found that both interventions increased immediate heart rate variability. Music listening resulted in decreased N2 sleep, increased frontal beta1 power spectral density, and a trend towards increased N3 sleep was detected. In the slow breathing condition higher central delta power during N3 was observed. While some indices pointed to improved sleep quality in both intervention groups, neither condition had robust effects on sleep quality. These explorative findings warrant further replication in different populations.Peer reviewe

The Effects of Pre-Sleep Slow Breathing and Music Listening on Objective Sleep Quality and Declarative Memory Consolidation

Tavoitteet. Aiempien tutkimusten valossa hidas hengitys resonanssitaajuudella voi parantaa unen laatua. Näissä aiemmissa tutkimuksissa on kuitenkin ollut metodologisia heikkouksia. Musiikin kuuntelu on suosittu itseapukeino unen parantamiseen, mutta tutkimustulokset musiikin vaikutuksesta unen laatuun ovat olleet vaihtelevia. Unen tiedetään vaikuttavan muistikonsolidaatioon, mutta hitaan hengityksen ja musiikin kuuntelun vaikutuksista muistikonsolidaatioon ei ole juurikaan tutkimustietoa. Tämän tutkimuksen tavoitteena oli selvittää, miten kaksi interventiota, hidas hengitys arvioidulla resonanssitaajuudella ja musiikin kuuntelu, vaikuttavat objektiiviseen unen laatuun ja yön yli tapahtuvaan muistikonsolidaatioon. Menetelmät. Tutkimus oli satunnaistettu kontrolloitu tutkimus vaihtovuoroisella asetelmalla. 20 koehenkilöä (10 naista) satunnaistettiin koeryhmään, joka hengitti hitaassa tahdissa, tai verrokkiryhmään, joka kuunteli musiikkia ennen nukkumaanmenoa puolen tunnin ajan. Koehenkilöiden unta mitattiin kahtena peräkkäisenä yönä polysomnografialla. Toisena iltana koehenkilöt tekivät heille määrätyn intervention, ja toinen ilta toimi kontrollitilanteena. Muistisuoriutumista mitattiin assosioiduilla sanapareilla. Tulokset analysoitiin lineaarisella sekamallilla. Tulokset ja johtopäätökset. Hidas hengitys paransi deklaratiivisen muistin konsolidaatiota mutta ei parantanut unen laatua verrattuna kontrollitilanteeseen. Musiikin kuuntelu ei vaikuttanut muistisuoritukseen, mutta se paransi unen laatua vähentämällä yönaikaista hereilläoloaikaa, lyhentämällä N1-, N2- ja non-REM- unta sekä lisäämällä N3-unen osuutta kontrollitilanteeseen verrattuna. Tulosten perusteella musiikin kuuntelu voi parantaa objektiivista unen laatua ja hidas hengitys taas yön yli tapahtuvaa oppimista. Lisätutkimukset ovat kuitenkin tarpeen, jotta näiden yhteyksien väliset mekanismit voidaan ymmärtää paremmin.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