Effect of off-road competitive motocross race on plasma oxidative stress and damage markers.
OBJECTIVE
To analyse the effect of an off-road motocross heat on plasma levels of oxidative stress and damage, blood leucocyte counts and urine catecholamine concentration.


METHODS
Plasma contents of total, reduced and oxidised (GSSG) glutathione, %GSSG, malondialdehyde (MDA), protein carbonyl and sulphydryl groups, total antioxidant status (TAS), uric acid, and blood neutrophil and lymphocyte counts were evaluated in 10 male top-level riders before, immediately after (0 h) and 1 h after a simulated competitive motocross race. 24-h urine adrenaline, noradrenaline and dopamine concentrations were also measured.


RESULTS
The motocross heat resulted in an increase in plasma oxidative stress and damage (p<0.05). This was shown by a significant increase in %GSSG, TAS, MDA and carbonyls, and by a decrease in sulphydryl groups after the race. There was a significant increase in both plasma uric acid and urine catecholamine concentration after the race (p<0.05). Blood neutrophil counts increased at 0 and 1 h after exercise (p<0.05). Lymphocyte count increased from baseline to 0 h, although it decreased from baseline and 0 to 1 h after exercise (p<0.05).


CONCLUSIONS
The data reinforce the marked metabolic and hormonal demands imposed by motocross, resulting in a condition of enhanced plasma oxidative stress and damage.
Ascensão
António
A
Research Center in Physical Activity, Health and Leisure, Faculty of Sports Sciences, University of Porto, Porto 4200-450, Portugal. aascensao@fcdef.up.pt
Ferreira
Rita
R
Marques
Franklim
F
Oliveira
Eduardo
E
Azevedo
Victor
V
Soares
José
J
Magalhães
José
J
D000328:Adult; D015415:Biomarkers / Q000097:blood*; D002395:Catecholamines / Q000652:urine; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D015541:Off-Road Motor Vehicles; D018384:Oxidative Stress / Q000502:physiology*; D013177:Sports / Q000502:physiology*
D015415:Biomarkers; D002395:Catecholamines