title: Effects of acute, intermittent exercise in hypoxic environments on the release of cardiac troponin.
abstract: The purpose of this study was to examine the effects of acute, intermittent exercise performed in hypoxic environments on the release of cardiac troponin (cTn). Ten well-trained, male marathon runners (22.1 ± 2.6 years, 64.0 ± 4.9 kg and 177.3 ± 3.9 cm) completed three intermittent exercise protocols under normoxic (trial N) and hypoxic (trial AH and RH) conditions. In trial N, the fraction of inspiration oxygen (FIO2 ) was 21.0% and exercise intensity was 90% and 50% normoxic velocity of VO2max (vVO2max). In trial AH, FIO2 was 14.4% (simulated altitude of 3000 m) and exercise intensity was 90% and 50% normoxic vVO2max. In trial RH, FIO2 was 14.4% and exercise intensity was 90% and 50% hypoxic vVO2max. High-sensitivity cardiac troponin T (hs-cTnT) and cardiac troponin I (cTnI) were measured pre- and 0, 2, 4, and 24 h post-exercise. Hs-cTnT was elevated in all three trials, peaking at 2 to 4 h and returning to the baseline 24 h post-exercise. CTnI increased in trial AH, peaking at 2 to 4 h and returning below the detection limit 24 h post-exercise. It is concluded that the stimulus of hypoxia did not in and of itself induce more cTn to be released, but exercise intensity could affect this response in hypoxic environments.
authors.affiliation: Department of Physical Education, Hebei Normal University for Nationalities, Chengde, China.
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.affiliation: Sport Science Research Centre, Beijing Sport University, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Hu
authors.affiliation: School of Physical Education and Sports, Macao Polytechnic Institute, Macao, China.
authors.forename: J
authors.initials: J
authors.lastname: Nie
authors.affiliation: Dr Stephen Hui Research Centre for Physical Recreation and Wellness, Hong Kong Baptist University, Hong Kong, China.
authors.forename: F H
authors.initials: FH
authors.lastname: Fu
mesh_terms: D000531:Altitude; D056352:Athletes; D004777:Environment; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption; D064797:Physical Conditioning, Human / Q000379:methods*; D012420:Running / Q000502:physiology*; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*; D055815:Young Adult
chemical_list: D019210:Troponin I; D020107:Troponin T
keywords: Cardiac biomarkers; cTnI; exercise-induced cTn release; hs-cTnT; hypoxia; intermittent exercise