Normal values and reproducibility of the real-time index of vagal tone in healthy humans: A multi-center study

Adam D. Farmer, Steven J. Coen, Michiko Kano, Nathalie Weltens, Huynh Giao Ly, Claude Botha, Peter A. Paine, Lukas Van Oudenhove, Qasim Aziz

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Background The parasympathetic nervous system has been implicated in the pathogenesis of a number of gastrointestinal disorders including irritable bowel syndrome. Within the field, cardiometric parameters of parasympathetic/vagal tone are most commonly derived from time, or frequency, domain analysis of heart rate variability (HRV), yet it has limited temporal resolution. Cardiac vagal tone (CVT) is a non-invasive beat-to-beat measure of brainstem efferent vagal activity that overcomes many of the temporal limitations of HRV parameters. However, its normal values and reproducibility in healthy subjects are not fully described. The aim of this study was to address these knowledge gaps. Methods 200 healthy subjects (106 males, median age 28 years, range 18-59 years) were evaluated across three study centers. After attachment of CVT recording equipment, 20 min of data (resting/no stimulation) was acquired. 30 subjects, selected at random, were restudied aft er 1 year. Results The mean CVT was 9.5±4.16 linear vagal scale (LVS). Thus, the normal range (mean±2 standard deviations) for CVT based on this data was 1.9-17.8 LVS. CVT correlated negatively with heart rate (r=-0.6, P=0.001). CVT reproducibility over 1 year, as indexed by an intra-class correlational coefficient of 0.81 (95% confidence interval 0.64-0.91), was good. Conclusions In healthy subjects, the normal range for CVT should be considered to be 1.9-17.8 LVS and is reproducible over 1 year. Future research utilizing CVT should refer to these values although further study is warranted in patient groups.

Original languageEnglish
Pages (from-to)362-368
Number of pages7
JournalAnnals of Gastroenterology
Issue number4
Publication statusPublished - 2014


  • Autonomic nervous system
  • Cardiac vagal tone
  • Parasympathetic nervous system

ASJC Scopus subject areas

  • Gastroenterology


Dive into the research topics of 'Normal values and reproducibility of the real-time index of vagal tone in healthy humans: A multi-center study'. Together they form a unique fingerprint.

Cite this