title: The effects of exercise at high altitude on high-sensitivity cardiac troponin release and associated biventricular cardiac function.
abstract: BACKGROUND
  It has been consistently shown that heavy exercise leads to cardiac troponin (cTn) release and variable changes in post exercise cardiac function. This relationship has not been explored at increasing or significant high altitude (HA). This study assessed the effects of exercise at progressively increasing HA on high-sensitivity (hs)-cTnT levels and their relationship to biventricular cardiac function and severity of acute mountain sickness (AMS).
  
  
  METHODS
  Transthoracic echocardiograms, hs-cTnT levels and AMS scores were measured at rest at 1,300 m then repeated post exercise and 12 h later after progressive trekking to 3,440, 4,270 m and at 5,150 m (after trekking to 5,643 m) on 19 healthy subjects (age 35.4 ± years, 52.6 % males).
  
  
  RESULTS
  There was a detectable increase (>5 ng/L) in post exercise hs-cTnT with exercise at HA which became significant at 5,150 m (5.84 % at 3,440 m, 5.2 % at 4,270 m and 56.3 % at 5,150 m; p = 0.0005). Compared with baseline, HA to 5,150 m led to a significant rise in post exercise Lake Louis AMS scores (p < 0.001) pulmonary artery systolic pressure (PASP) (23.7 ± 3.8 vs 37.9 ± 11.7 mmHg: p < 0.001), cardiac output (5.2 ± 1.2 vs 7.5 ± 1.3 l/min; p < 0.001) and a fall in SpO2 (96.1 ± vs 77.4 ± 12.0 %; p < 0.001). There was no change in stroke volume (p = 0.10) or estimated filling pressures (E/E') of the left (p = 0.50) and right ventricles (p = 0.4). On multivariate analysis increasing cardiac output (p = 0.02) and PASP (p = 0.04) and decreasing SpO2 (p = 0.01) were the only independent predictors of increasing cTnT levels (overall R (2) = 0.23, p < 0.0001).
  
  
  CONCLUSIONS
  Moderate intensity exercise at significant HA influences the post exercise increase in hs-cTnT without overt deleterious effects on cardiac function.
authors.affiliation: Department of Cardiology, Poole Hospital NHS Foundation Trust, Longfleet Rd. Poole, Dorset, BH15 2JB, UK, christopherboos@hotmail.com.
authors.forename: Christopher John
authors.initials: CJ
authors.lastname: Boos
authors.forename: Adrian
authors.initials: A
authors.lastname: Mellor
authors.forename: Joe
authors.initials: J
authors.lastname: Begley
authors.forename: Michael
authors.initials: M
authors.lastname: Stacey
authors.forename: Chris
authors.initials: C
authors.lastname: Smith
authors.forename: Amanda
authors.initials: A
authors.lastname: Hawkins
authors.forename: David Richard
authors.initials: DR
authors.lastname: Woods
mesh_terms: D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000097:blood* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002302:Cardiac Output / Q000502:physiology*; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology*; D020107:Troponin T / Q000097:blood*; D055815:Young Adult
chemical_list: D020107:Troponin T