Resting Heart Rate Variability (HRV) in Adolescents and Young Adults from a Genetically-Informed Perspective
Reduced heart rate variability (HRV) is associated with cardiac morbidity, mortality, and negative psychopathology. Most research concerning genetic influences on HRV has focused on adult populations, with fewer studies investigating the developmental period of adolescence and emerging adulthood. The current study estimated the genetic and environmental contributions to resting HRV in a sample of twins using various HRV time domain metrics to assess autonomic function across two different time measurement intervals (2.5- and 10-min). Five metrics of resting HRV [mean interbeat interval (IBI), the standard deviation of normal IBIs (SDNN), root square mean of successive differences between IBIs (RMSSD), cardiac vagal index (CVI), and cardiac sympathetic index (CSI)] were assessed in 421 twin pairs aged 14–20 during a baseline electrocardiogram. This was done for four successive 2.5-min intervals as well as the overall 10-min interval. Heritability (h2) appeared consistent across intervals within each metric with the following estimates (collapsed across time intervals): mean IBI (h2 = 0.36–0.46), SDNN (h2 = 0.23–0.30), RMSSD (h2 = 0.36–0.39), CVI (h2 = 0.37–0.42), CSI (h2 = 0.33–0.46). Beyond additive genetic contributions, unique environment also was an important influence on HRV. Within each metric, a multivariate Cholesky decomposition further revealed evidence of genetic stability across the four successive 2.5-min intervals. The same models showed evidence for both genetic and environmental stability with some environmental attenuation and innovation. All measures of HRV were moderately heritable across time, with further analyses revealing consistent patterns of genetic and environmental influences over time. This study confirms that in an adolescent sample, the time interval used (2.5- vs. 10-min) to measure HRV time domain metrics does not affect the relative proportions of genetic and environmental influences.
KeywordsHeart rate variability Heritability Time metrics Time intervals Adolescence Psychophysiology
We would like to thank the participants from the Adolescent and Young Adult Twin Study (AYATS), as well as the many VCU students who contributed to execution of the project, particularly Jason Burchett. We would also like to thank Audrey Anderson for her assistance collecting and processing the data and Shannon Hahn and Jennifer Cecilione for their work as project coordinators.
The AYATS is funded by NIMH R01MH101518 (PI: RRN). AAM is supported by NIMH F31MH111229. JLB, MLE, and JES are supported by NIMH T32MH020030. LH is supported by NIMH R01MH101518. JMH is supported by NIMH R01MH098055.
Compliance with ethical standards
Conflict of interest
Jessica L. Bourdon, Ashlee A. Moore, Meridith Eastman, Jeanne E. Savage, Laura Hazlett, Scott R. Vrana, John M. Hettema, Roxann Roberson-Nay declare that they have no conflict of interest.
Informed consent/assent was collected for all participants and procedures were approved the university’s Institutional Review Board.
Human and animal rights
All human subjects ethical standards were followed by all authors and research assistants who worked on the AYATS. Each individual involved in the project is up-to-date on Collaborative Institutional Training Initiative (CITI) and MATR training.
- BIOPAC Systems, Inc (2010) Acqknowledge for MP Systems, version 4.1.1. http://www.biopac.com
- Howell DC (1998) Statistical methods in human sciences. Wadsworth, New YorkGoogle Scholar
- Munoz ML, van Roon A, Riese H, Thio C, Oostenbroek E, Westrik I, de Geus EJ, Gansevoort R, Lefrandt J, Nolte IM, Snieder H (2015) Validity of (ultra-) short recordings for heart rate variability measurements. PLoS ONE 10(9):e0138921. https://doi.org/10.1371/journal.pone.0138921 CrossRefPubMedPubMedCentralGoogle Scholar
- R Development Core Team (2008) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0. http://www.R-project.org