Published in:
01-12-2005 | Original Article
The effects of an antioxidant-supplemented beverage on exercise-induced oxidative stress: results from a placebo-controlled double-blind study in cyclists
Authors:
J. Morillas-Ruiz, P. Zafrilla, M. Almar, M. J. Cuevas, F. J. López, P. Abellán, J. A. Villegas, J. González-Gallego
Published in:
European Journal of Applied Physiology
|
Issue 5-6/2005
Login to get access
Abstract
The objective of this study was to test the effects of an antioxidant-supplemented beverage on exercise-induced oxidative stress in moderately trained cyclists. A double-blind study was conducted in moderately trained cyclists. They were randomly allocated to receive either an antioxidant (13 subjects) or a placebo (13 subjects) 15 min pre-exercise (30 ml.kg−1) and during a 90 min constant-load test (30 ml.kg−1.15 min−1) on a bicycle ergometer at 70%
\({\dot{{\it V}}}{\text{O}}_{2\max}.\) The supplemented beverage contained black grape (81 g/l), raspberry (93 g/l) and red currant (39 g/l) concentrates, and its total antioxidant capacity, measured by the ABTS.+ technique, was 0.41 mM Trolox. No significant difference from basal to post-exercise period was detected for plasma TBARS in either the placebo group or the group receiving the antioxidant supplemented beverage. Post-exercise carbonyls decreased by 29% in the group receiving antioxidants, and the pattern of change was significantly different between antioxidant and placebo conditions. The urinary excretion of 8-OHdG increased significantly by 21% in the placebo group. Again differences in the pre- to post-exercise change were significant between both conditions These results suggest that in moderately trained cyclists, antioxidant supplementation counters oxidative stress induced by a 90 min exercise at 70%
\({\dot{{\it V}}}{\text{O}}_{2\max}.\)