title: Effect of prolonged walking on cardiac troponin levels.
abstract: Increased cardiac troponin I (cTnI), a marker for cardiac damage, has been reported after strenuous exercise in young subjects. However, little is known about changes in cTnI after moderate-intensity exercise in a heterogenous population or which factors may contribute to this change in cTnI levels. We examined cTnI levels before and immediately after each day of a 4-day long-distance walking event (30 to 50 km/day) in a heterogenous group (67 men, 42 women), across a broad age range (21 to 82 years), with known cardiovascular pathology or risk factors present in many subjects (n = 24). Walking was performed at a self-selected pace. Cardiac TnI was assessed using a standard system (Immulite) with high values (>or=0.20 microg/L) cross-checked using a high-sensitive cTnI assay (Centaur). Mean cTnI levels increased significantly from 0.04 to 0.07 microg/L on day 1, with no further increase thereafter (p <0.001, analysis of variance). Backward linear regression found a weak, but significant, association of age (p <0.001), walking speed (p = 0.02), and cardiovascular pathology (p = 0.03) with postexercise cTnI level (combined r(2) = 0.11, p <0.001). In 6 participants (6%), cTnI was increased above the clinical cut-off value for myocardial infarction on >or=1 day. These participants supported the regression analysis, because they were older, walked at higher relative exercise intensity, and reported a high prevalence of cardiovascular pathology. In conclusion, prolonged, moderate-intensity exercise may result in an increase in cTnI levels in a broad spectrum of subjects, especially in older subjects with pre-existing cardiovascular disease or risk factors.
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Thijs
authors.initials: T
authors.lastname: Eijsvogels
authors.forename: Keith
authors.initials: K
authors.lastname: George
authors.forename: Rob
authors.initials: R
authors.lastname: Shave
authors.forename: David
authors.initials: D
authors.lastname: Gaze
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Levine
authors.forename: Maria T E
authors.initials: MT
authors.lastname: Hopman
authors.forename: Dick H J
authors.initials: DH
authors.lastname: Thijssen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001831:Body Temperature; D002318:Cardiovascular Diseases / Q000097:blood* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology; D010809:Physical Fitness; D012737:Sex Factors; D013997:Time Factors; D019210:Troponin I / Q000097:blood*; D016138:Walking / Q000502:physiology*; D055815:Young Adult
chemical_list: D019210:Troponin I