title: No indications of persistent oxidative stress in response to an ironman triathlon.
abstract: BACKGROUND
  Training for and competing in ultraendurance exercise events is associated with an improvement in endogenous antioxidant defenses as well as increased oxidative stress. However, consequences on health are currently unclear.
  
  
  OBJECTIVE
  We aimed to examine the impact of training- and acute exercise-induced changes in the antioxidant capacity on the oxidant/antioxidant balance after an ironman triathlon and whether there are indications for sustained oxidative damage.
  
  
  METHODS
  Blood samples were taken from 42 well-trained male triathletes 2 d before an ironman triathlon, then immediately postrace, 1, 5, and 19 d later. Blood was analyzed for conjugated dienes (CD), malondialdehyde (MDA), oxidized low-density lipoprotein (oxLDL), oxLDL:LDL ratio, advanced oxidation protein products (AOPP), AOPP:total protein (TP) ratio, Trolox equivalent antioxidant capacity (TEAC), uric acid (UA) in plasma, and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in erythrocytes.
  
  
  RESULTS
  Immediately postrace, there were significant increases in CD, AOPP, TEAC, UA (for all P < 0.001), and AOPP:TP (P < 0.01). MDA rose significantly (P < 0.01) 1 d postrace, whereas CD (P < 0.01), AOPP (P = 0.01), AOPP:TP (P < 0.05), and TEAC (P < 0.001) remained elevated. OxLDL:LDL trended to increase, whereas oxLDL significantly (P < 0.01) decreased 1 d postrace. Except for GSH-Px (P = 0.08), activities of SOD (P < 0.001) and CAT (P < 0.05) significantly decreased postrace. All oxidative stress markers had returned to prerace values 5 d postrace. Furthermore, several relationships between training status and oxidative stress markers, TEAC, and antioxidant enzyme activities were noted.
  
  
  CONCLUSIONS
  This study indicates that despite a temporary increase in most (but not all) oxidative stress markers, there is no persistent oxidative stress in response to an ironman triathlon, probably due to training- and exercise-induced protective alterations in the antioxidant defense system.
authors.affiliation: Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Neubauer
authors.forename: Daniel
authors.initials: D
authors.lastname: König
authors.forename: Norbert
authors.initials: N
authors.lastname: Kern
authors.forename: Lukas
authors.initials: L
authors.lastname: Nics
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Wagner
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D001642:Bicycling; D015415:Biomarkers / Q000097:blood; D002374:Catalase / Q000097:blood; D015444:Exercise; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D008297:Male; D018384:Oxidative Stress; D010807:Physical Endurance; D012420:Running; D013177:Sports; D013482:Superoxide Dismutase / Q000097:blood; D013550:Swimming
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase