title: Ambulatory measurement of the ECG T-wave amplitude.
abstract: Ambulatory recording of the preejection period (PEP) can be used to measure changes in cardiac sympathetic nervous system (SNS) activity under naturalistic conditions. Here, we test the ECG T-wave amplitude (TWA) as an alternative measure, using 24-h ambulatory monitoring of PEP and TWA in a sample of 564 healthy adults. The TWA showed a decrease in response to mental stress and a monotonic decrease from nighttime sleep to daytime sitting and more physically active behaviors. Within-participant changes in TWA were correlated with changes in the PEP across the standardized stressors (r = .42) and the unstandardized naturalistic conditions (mean r = .35). Partialling out changes in heart rate and vagal effects attenuated these correlations, but they remained significant. Ambulatory TWA cannot replace PEP, but simultaneous recording of TWA and PEP provides a more comprehensive picture of changes in cardiac SNS activity in real-life settings.
authors.affiliation: Department of Biological Psychology, VU University Amsterdam, Amsterdam, The Netherlands, and EMGO+ Institute, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: van Lien
authors.forename: Melanie
authors.initials: M
authors.lastname: Neijts
authors.forename: Gonneke
authors.initials: G
authors.lastname: Willemsen
authors.forename: Eco J C
authors.initials: EJ
authors.lastname: de Geus
mesh_terms: D000328:Adult; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D013315:Stress, Psychological / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014427:Twins
keywords: Behavioral medicine; Genetics; Heart rate; Individual differences; PEP; RSA