title: Decreased chronotropic drive as an adaptation to chronic exercise; possible mechanisms.
abstract: Cardiovascular function was determined at rest and during exercise in twenty-eight healthy, elite distance runners. Maximum heart rate was 184 +/- 6 b x min(-1), which was more than one SD lower than the age predicted value (p < 0.001), and an inverse correlation was observed between maximum heart rate and VO2max (r = - 0.82, p < 0.001). The most aerobically trained athlete, a 27 year old male, presented with a maximum heart rate of 139b x min(-1). Echo-cardiac ultrasound revealed unremarkable intra-cardiac dimensions and flow characteristics relative to other endurance-trained athletes. A decreased chronotropic drive may represent a favourable physiological adaptation to endurance exercise which increases cardiovascular efficiency.
authors.affiliation: Health and Exercise Sciences Research Laboratory, School of Applied Sciences, University of Glamorgan, Pontypridd, S. Wales, UK. dbailey1@glam.ac.uk
authors.forename: D M
authors.initials: DM
authors.lastname: Bailey
authors.forename: B
authors.initials: B
authors.lastname: Davies
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000367:Age Factors; D002320:Cardiovascular Physiological Phenomena; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D010809:Physical Fitness / Q000502:physiology*