title: Letter by Monfredi et al regarding article, "Physical activity and heart rate variability in older adults: the cardiovascular health study".
authors.affiliation: Institute of Cardiovascular Sciences, University of Manchester, Manchester, UK.
authors.forename: Oliver
authors.initials: O
authors.lastname: Monfredi
authors.affiliation: Biological Physics Group, University of Manchester, Manchester, UK.
authors.forename: Henggui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Institute of Cardiovascular Sciences, University of Manchester, Manchester, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Boyett
mesh_terms: D002318:Cardiovascular Diseases / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006304:Health Status; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D016138:Walking / Q000502:physiology*