title: Music structure determines heart rate variability of singers.
abstract: Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1-3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior.
authors.affiliation: Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg Gothenburg, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Vickhoff
authors.forename: Helge
authors.initials: H
authors.lastname: Malmgren
authors.forename: Rickard
authors.initials: R
authors.lastname: Aström
authors.forename: Gunnar
authors.initials: G
authors.lastname: Nyberg
authors.forename: Seth-Reino
authors.initials: SR
authors.lastname: Ekström
authors.forename: Mathias
authors.initials: M
authors.lastname: Engwall
authors.forename: Johan
authors.initials: J
authors.lastname: Snygg
authors.forename: Michael
authors.initials: M
authors.lastname: Nilsson
authors.forename: Rebecka
authors.initials: R
authors.lastname: Jörnsten
keywords: autonomic nervous system; choral singing; frequency analysis; heart rate variability; respiratory sinus arrhythmia