No indications of persistent oxidative stress in response to an ironman triathlon.
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.
Neubauer
Oliver
O
Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Austria.
König
Daniel
D
Kern
Norbert
N
Nics
Lukas
L
Wagner
Karl-Heinz
KH
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
D000975:Antioxidants; D015415:Biomarkers; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase