title: Sampling time is crucial for measurement of aerobic exercise-induced oxidative stress.
abstract: OBJECTIVE
  To thoroughly investigate the time-course changes of several commonly used markers of oxidative stress by performing serial measurements during a 24-h period after an acute bout of strenuous cardiovascular exercise.
  
  
  METHODS
  Eleven untrained men performed two trials. In the experimental trial, the subjects exercised for 45 min at 70-75% VO2max and then at 90% VO2max to exhaustion on a treadmill; in the control trial, the subjects remained at rest. Blood samples were drawn before and after exercise (immediately after exercise and at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, and 24 h). Reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, thiobarbituric acid-reactive substances (TBARS), protein carbonyls, catalase activity, and total antioxidant capacity (TAC) were determined.
  
  
  RESULTS
  The time to lowest concentration after exercise was 1.7 +/- 0.7 h (mean +/- SD) for GSH/GSSG, and the time to highest concentration after exercise was 1.2 +/- 0.6 h for TBARS, 4.4 +/- 0.5 h for protein carbonyls, 0.5 +/- 0.4h for catalase, and 2.2 +/- 0.9 h for TAC. The greatest change after exercise was -74 +/- 9% for GSH/GSSG, 129 +/- 29% for TBARS, 135 +/- 53% for protein carbonyls, 51 +/- 16% for catalase, and 24 +/- 10% for TAC.
  
  
  CONCLUSIONS
  There is no best time point applying to all markers for collecting blood samples after aerobic exercise. The optimum postexercise time points for blood collection in untrained individuals are immediately after exercise for catalase, 1 h for TBARS, 2 h for TAC, GSH, and GSSG, and 4 h after exercise for protein carbonyls.
authors.affiliation: Department of Physical Education and Sport Science, Democritus University of Thrace, Komotini, Greece.
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Michailidis
authors.forename: Athanasios Z
authors.initials: AZ
authors.lastname: Jamurtas
authors.forename: Michalis G
authors.initials: MG
authors.lastname: Nikolaidis
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Fatouros
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papassotiriou
authors.forename: Dimitris
authors.initials: D
authors.lastname: Kouretas
mesh_terms: D000293:Adolescent; D000328:Adult; D002374:Catalase / Q000032:analysis; D015444:Exercise / Q000502:physiology*; D005978:Glutathione / Q000032:analysis / Q000097:blood; D006115:Greece; D006403:Hematologic Tests / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D050050:Protein Carbonylation; D012107:Research Design; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors
chemical_list: D017392:Thiobarbituric Acid Reactive Substances; D002374:Catalase; D005978:Glutathione